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Language：Japanese   Publisher：Japan Society for Science Education  

DOI： 10.14935/jsser.35.6_31

CiNii Research

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Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

CiNii Books

CiNii Research

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Other Link： http://id.ndl.go.jp/bib/029914590

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Magnetic and neutron diffraction measurements were performed in an orthorhombic DyPdSn compound. The magnetic properties are highly anisotropic; the easy axis of magnetization is the b-axis and the hard axis is the a-axis above 30 K whereas it is the c-axis below it. This behavior is well reproduced by the CEF calculation based on a point charge model and a comparison of deduced CEF parameters is made with isostructural equiatomic ternary Dy and Tb compounds. A successive magnetic phase transition has been observed below the Neel temperature T-N = 10.8 K; the four magnetic phases exist respectively in T < T-1 = 2.5 K, T-1 < T < T-2 = 4.7 K, T-2 < T < T-3 = 6.2 K and T-3 < T < TN. Multi-step metamagnetic transitions have been observed along the three principal axes. The powder neutron diffraction patterns have indicated that the magnetic structure is described by the propagation vector k - (0.21, 0, 0.66) at 3.4 K. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2016.09.121

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Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

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Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

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Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

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Language：Japanese   Publisher：Japan Society for Science Education  

DOI： 10.14935/jssep.40.0_289

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Language：Japanese   Publisher：愛媛大学教育学部  

CiNii Books

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.17265/2161-6221/2015.3-4.007

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Language：Japanese  

CiNii Books

J-GLOBAL

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Language：Japanese   Publisher：Japan Society for Science Education  

<p>本研究では愛媛大学教育学部理科教育講座で実践している「理科観察実験体験プログラム」で実施している質問紙を分析し，学生の観察・実験の指導力向上について考察した。その結果，観察・実験の指導力向上には観察・実験の指導に対する省察が重要であること，一度の実践では指導力育成には不十分であることが明らかとなった。また，観察・実験に関する知識理解と指導のスキルを統合する機会が必要であることが示唆された。</p>

DOI： 10.14935/jssep.39.0_334

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J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

New equipment has been developed for evaluating the figure of merit, ZT, on the basis of the Harman method in the temperature range between room temperature and 650 K. In this temperature range, the sample holder in the vacuum chamber has a different construction as compared with the sample holder constructed for the temperature range below room temperature. Several issues that need to be considered, such as compensation for the thermal radiation effect, suppression of heat leakage from the lead wires, and the setup method for the lead wires on the sample, are examined in the considered temperature region. Evaluations of ZT are successfully made for typical thermoelectric materials, (Bi,Sb)(2)Te-3 and CeFe3CoSb12. We then demonstrate that the influence of thermal radiation between the high- and low-temperature edges of the sample induced by the Peltier effect on the estimated value of ZT is negligible at around 600 K. Furthermore, the change in the thermoelectric properties due to repetition of the thermal cycle is studied, and a typical hysteresis behavior is observed in the considered thermoelectric materials. It is revealed that heating the sample to a high temperature causes a change in its thermoelectric properties, which one must take into account for practical applications of thermoelectric materials.

DOI： 10.1007/s11664-012-2448-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

A Seebeck micro-probe measurement system with high spatial resolution has been developed to examine two-dimensional spatial distribution of Seebeck coefficient for thermoelectric materials at room temperature. A contact area of 10 mu m phi is realized by using a Copper probe tip fabricated by a mechanical machining process. The two-dimensional spatial distribution of the Seebeck coefficient for the Bismuth-Telluride and Zinc-Antimonide systems has been measured. The sign inversion of the Seebeck coefficient from p- to n-type is clearly detected along the crystal growth direction in the Bismuth-Telluride system. On the other hand, the anisotropic Seebeck coefficient reflecting grain distribution is conspicuously observed in the Zinc Antimonide system. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.intermet.2012.08.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

ASm7Rh3 single crystal with Th7Fe 3-type hexagonal structure was grown by the Czochralski method. The magnetic and transport measurements revealed a uniaxial magnetocrystalline anisotropy in the magnetic susceptibility, magnetization and electrical resistivity. Sm7Rh3 was found to exhibit antiferro- magnetic transition at TN = 54.0 K and another magnetic transition at Tt=25.0 K. The specific heat data clearly showed the bulk nature of paramagnetic to ordered magnetic phase transition by the presence of a sharp peak at TN and a small anomaly at Tt. The paramagnetic susceptibility does not obey the CurieWeiss law, attributing to the temperature independent Van Vleck contribution and Pauli paramagnetism of conduction electrons. Metamagnetic phase transitions were observed along the c-axis in the ordered states. The magnetic field H-temperature T phase diagram was constructed. Anisotropic paramagnetic electrical resistivity showed the small negative temperature coefficients. © 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2013.06.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Structural and thermoelectric properties have been investigated for (Zn1-xCdx)(13)Sb-10 compounds prepared by a gradient freeze method. The crack-free single phase of the (Zn1-xCdx)(13)Sb-10 was obtained with the starting Cd composition up to x = 0.4. The large distribution of the chemical composition has been elucidated along the growth direction in the ingots prepared; Cd is poor in the lower part of the ingots, while the chemical composition is nearly the same as the starting one in the upper part. The lattice constants increase with increasing Cd content. The Seebeck coefficient and electrical resistivity are enhanced, whereas the thermal conductivity is strongly decreased by 20% by the Cd substitution, leading to the enhancement of the dimensionless figure of merit by 10% at x = 0.30 at 340 K. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.intermet.2011.11.021

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

A Seebeck microprobe (SMP) measurement system has been developed and employed to determine the spatial distribution of the Seebeck coefficient of a polycrystalline Zn13Sb10 specimen prepared by a gradient freeze (GF) method. The spatial distribution of the Seebeck coefficient strongly reflects that of the grains observed using an optical polarizing microscope, the magnitude of which ranges from 100 mu V/K to 130 mu V/K. This fact strongly indicates that the observed spatial distribution of the Seebeck coefficient arises from the anisotropic Seebeck effect of grains with different crystal orientations in the polycrystalline Zn13Sb10.

DOI： 10.1007/s11664-009-0818-z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Structural, metallurgical, and low-temperature thermoelectric properties have been investigated for Zn13+xSb10 compounds prepared by the gradient freeze and vacuum melt-quench methods at various starting Zn compositions. The Rietveld analysis of the powder x-ray diffraction profiles indicates that the excess Zn occupies mainly the 36f-3 and 36f-4 interstitial sites. It is also revealed that the actual Zn composition and lattice constants have strong correlation with occupation factors of the 36f-3 and 36f-4 sites. The thermoelectric property strongly depends on the actual Zn composition. The enhancement in the electrical resistivity and Seebeck coefficient associated with the beta to alpha structural phase transition is more remarkable for the samples with larger starting Zn composition. On the other hand, the lattice thermal conductivity also exhibits a remarkable increase at the transition temperature, indicating an ordered Zn structure in the alpha phase. These facts indicate that the occupation of Zn in the two interstitial 36f-3 and 36f-4 sites gives a significant effect on the crystal and electronic structures of the Zn13+xSb10 system. (C) 2009 American Institute of Physics.

DOI： 10.1063/1.3043884

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Structural, metallurgical and thermoelectric properties have been investigated below room temperature for Zn(13-x)Sbi(10) compounds prepared by a gradient freeze method with various starting compositions. The clectfon-probe microanalysis and the Rietveld analysis of the powder X-ray diffraction profiles indicate that the composition range of the P-phase is narrow irrespective of starting composition. A strong relation is found between the electrical resistivity and Seebeck coefficient. The dimensionless figure of merit in the P-phase takes a larger value in the ingots prepared with Zn-rich starting composition. (C) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2006.07.107

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Thermal analysis by differential scanning calorimetry (DSC) and thermal expansion measurement have been performed between room temperature and 873 K on near stoichiometric Zn4Sb3 Compounds prepared by a gradient freeze method with various starting compositions. It has been revealed that there is a strong correlation between the anomalies observed both in the DSC profile and thermal expansion and the existence of a segregated Zn impurity phase. Impurity-free sample shows a large linear expansion jump of 0.3% at 767 K. The samples including an impurity of Zn show a huge linear expansion jump of 1% associated with an endothermic reaction, due to the formation of the Zn3Sb2 phase at 686 K. (C) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2006.06.097

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The E-phase of Zn4Sb3 compound has been examined by the powder X-ray diffraction (XRD) and electron-probe micro analysis (EPMA) on three ingots prepared, respectively, by gradient freeze (GF), Bridgman (BR) and solid-state synthesis (SSS) with different starting compositions. It is found that the homogeneity range of the E-phase is narrow within 0.20 at.% Zn irrespective of different preparation methods and starting compositions. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2006.05.118

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Three preparation methods - quenching, sintering and annealing - have been employed to synthesize Y-filled skutterudite compounds YxCO4Sb12 (0.00 <= x <= 0.35). Y atoms do not fill the vacancy sites in the skutterudite structure in the form of YxCO4Sb12. YSb and CoSb2 are formed as impurity phases when Y is added. The lattice thermal conductivity is reduced by 30% by Y addition, indicating that the segregated impurity phases strongly scatter. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.scriptamat.2006.10.023

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Magnetic and neutron diffraction studies have been performed on an Er7Rh3 single crystal. The magnetic measurements show that there are two successive anti ferromagnetic transitions at T-N = 13.0 K and T-t1 = 6.2 K. A small magnetic anisotropy is observed in the paramagnetic susceptibility. Neutron diffraction also shows evidence of a commensurate to incommensurate magnetic transition at T-t2 = 4.5 K. The magnetic structure in the low temperature anti ferromagnetic phase below T-t2 is characterized by the two magnetic propagation vectors k(1) = (001/2) and k(2) = (000). With increasing temperature, the magnetic modulation characterized by k(2) disappears at T-t1 but the z-component is temperature independent. On the other hand, the magnetic modulation characterized by k(1) becomes incommensurate at T-t2 where k(1) = (000.42) and persists in the high temperature phase between T-t1 and T-N. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2006.05.049

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

The effect of hydrostatic pressure has been investigated on the thermoelectric properties of Zn4Sb3 compound prepared by a gradient freeze method. The electrical conductivity both in beta- and alpha-phases is largely enhanced with pressure: the relative change is 23.3%/GPa at 297 K. On the other hand, the thermopower at 297 K is decreased largely with pressure at -16.0 mu V K-1 GPa(-1) : the relative change is -13.6%/GPa. The almost pressure independent power factor is discussed based on a single band model. The resistivity behavior around the beta- to alpha-phase structural phase transition T, (258 K) is drastically changed with pressure. The thermal hysteresis width is narrowed in rho(T). The T-s is decreased at a rate of -26.2 K/GPa. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j/jallcom.2005.11.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

X-ray diffraction patterns and L-III-edge x-ray absorption near edge structure (XANES) spectra of YbInAu2 and LuInAu2 compounds have been measured at high pressure and room temperature using a diamond anvil cell and a synchrotron radiation at SPring-8. YbInAu2 is more compressible at pressures lower than 4 GPa than above it; the evaluated bulk modulus by Birch-type equation of state is 54.7 GPa which is one-half of that of the LuInAu2 (112.5 GPa). The mean valence (v) over bar of Yb ion in YbInAu2 determined by the XANES measurement is an increasing function of pressure: 2.71(2) at normal pressure and 2.94(2) at 10 GPa. The rate of increase in (v) over bar with pressure is two times larger at pressures below 4 GPa than that above 4 GPa. However, the (v) over bar is described by a linear increasing function of the lattice compression: (v) over bar = (v) over bar (0)+2.9 parallel to Delta V/V-0 parallel to where (v) over bar (0) is 2.71. The extrapolation to the trivalent state gives the critical pressure of 13 GPa. (c) 2006 American Institute of Physics.

DOI： 10.1063/1.2335388

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The successive magnetic transitions and magnetic structure of hexagonal Ho2In compound have been investigated by the magnetic, specific heat and powder X-ray and neutron diffraction measurements. Two magnetic phase transitions have been observed at the paramagnetic to ferromagnetic transition temperature T-c = 85.0(2) K and the magnetic order-order transition temperature T-t = 32.5(2) K. No antiferromagnetic reflections have been observed in the neutron diffraction patterns. The Rietveld analysis has indicated that the Ho atoms possess different moment values at two inequivalent sites: 8.8(2) mu(B) and 9.0(2) mu(B) at 2 K and 7.0(2) mu(B) and 7.4(2) mu(B) at 45 K, respectively. The moment direction from the hexagonal c-axis is 41(10)degrees at 2 K. At 45 K, the reliability factor takes so shallow minimum at around 26(20)degrees that one cannot exclude the alignment of moments along the c-axis in the higher temperature phase. A model is suggested for the magnetic structure change at T-t. (c) 006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.263

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The thermal variation of the specific, heat and magnetization curves has been measured in the orthorhombic TbPdSn single crystal. The successive magnetic transitions have been identified at T-1 = 2.5 K, T-2 = 12.2 K and T-N = 23.8 K. The magnetic entropy has been evaluated and discussed in the framework of crystal electric field (CEF) analysis performed in the previous work. The CEF energy scheme is presented. The high-field magnetization measurement up to 14 T along the b-axis exhibits a multistep metamagnetic transition. The metamagnetic step is described by n/20 x 7.7 mu(B)/f.u. (n: integer). (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.11.115

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The magnetic structure of a hexagonal intermetallic compound Nd7Ni3 has been studied by the neutron diffraction measurements. The Rietveld analysis was carried out to refine the structural and magnetic parameters. The refined propagation vector is Q = (000.32(2)) to describe the ferrimagnetic structure at 2.0 K. The magnetic moment of the Nd atom is 2.00(1), 2.09(1), 2.09(1) mu(B) for the sites I, II and III, respectively. The magnetic moment at the site I has the conical structure with the cone angle 22.00(1)degrees. The refined initial relative phase is 39.43(3)degrees for sites I and II and 41.43(5)degrees for sites II and III, respectively. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2005.04.083

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Single crystal neutron diffraction studies have been performed on the rare-earth ternary compound, DyNiSn. This crystal exhibits an incommensurate magnetic structure expressed by the propagation vector, Q = (0.662 0.3520) with its third harmonics at low temperatures. In an external magnetic field applied along the c-axis DyNiSn shows incommensurate modulation with Q = (10.3150) at 1.6 K, while along the easy magnetization direction of the b-axis a commensurate modulation with Q = (2/300) develops at 2 K. The results along the b-axis are fully consistent with the magnetization curve. (c) 2005 Published by Elsevier B.V.

DOI： 10.1016/j.jallcom.2005.04.059

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TRANS TECH PUBLICATIONS LTD  

Zn4Sb3 was successfully produced by a hot pressing technique, and its thermoelectric properties were investigated in the temperature range from 4K to 300K. The Seebeck coefficient, electrical conductivity, thermal conductivity, and thermoelectric figure of merit showed a discontinuity in variation at 242K, indicating the alpha-Zn4Sb3 to beta-Zn4Sb3 phase transformation. Lattice thermal conductivity was found to be dominant in the total thermal conductivity of Zn4Sb3. Therefore, it is expected that thermoelectric properties can be improved by reducing the lattice thermal conductivity inducing phonon scattering centers.

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Fe56Pt44 thin films have been prepared by RF magnetron sputtering on Si substrates. The substrate temperature was kept at 350 degrees C. The X-ray diffraction patterns of as-deposited FePt films exhibited a disordered structure. Annealing of the films at 650-685 degrees C for 1 h yielded an ordered L1(0) phase with FCT structure. The high value for coercivity H-C of 17 kOe was obtained at room temperature for the 68 nm thick film annealed at 685 degrees C. The hard magnetic properties as well as grain structure of the films strongly depend on the annealing conditions. (c) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmmm.2004.11.534

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We have investigated the thermoelectric and structural properties of (Zn1-xCdx)(4)Sb-3 compounds below 300 K. The electrical resistivity in the compounds is found to increase with increasing Cd concentration and to have a lower value below the beta to alpha structural phase transition temperature. The Seebeck coefficient also increases with increasing Cd content. However, the anomaly at the transition is suppressed. The beta to alpha structural transition temperature is almost independent of the Cd content. As a result, the power factor at 300 K takes a maximum of 6 x 10(-6) Wcm(-') K-2 at a Cd content of 0.2 and the discontinuity in the thermoelectric performance at the structural transition temperature is weakened by the Cd substitution. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2004.01.054

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The purpose of this study was to accurately determine the valency of Yb at high pressure and room temperature and to clarify the relation between the valence state and the crystal structure of Yb metal. L-III-edge X-ray absorption near-edge structure (XANES) spectra were measured to determine the valence state of Yb metal in the pressure range from 0 to 34.6 GPa at room temperature, using a diamond anvil cell (DAC) and synchrotron radiation at SPring-8. In the fcc phase, Yb metal exhibits mixed valence (the mean valence (ν) over bar > 2. 1). At the fcc-to-bcc phase transition, a 0.1 jump is found in (ν) over bar. In the bcc phase, (ν) over bar (P) is an increasing function of pressure with downward curvature, reaching only 2.55 at 26 GPa. The (ν) over bar is only 2.65 in the hcp phase at 34.6 GPa. A tendency for saturation in (ν) over bar (P) to values smaller than 3.0 is found. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2003.12.035

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DOI： 10.1016/j.jmmm.2003.11.169

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Low-temperature resistivity down to 0.3 K and temperature and magnetic field dependence of magnetization have been measured on a CeCo2Si2 single crystal. It has been revealed that the physical properties are well characterized as a valence fluctuating system and there is no indication of superconductivity down to 0.3 K. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmmm.2003.11.169

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The thermal variation of magnetic susceptibility of the orthorhombic TbPdSn single crystal indicates a successive magnetic transition at TN = 23.8 K, T1 = 12.2 K and T2 = 2.5 K. The magnetization along the b-axis exhibits a multi-step metamagnetic transition in the three ordered phases. The easy axis of magnetization is the b-axis as in other isoastructural Tb ternary compounds of TbNiSn and TbRhGe. A comparison is made for the CEF parameters in these three Tb compounds. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmmm.2003.11.289

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The structural and low-temperature thermoelectric properties were investigated in the temperature range from 4.2 to 300 K of Bi1.8Sb0.2Te3.0 grown by the gradient freeze method from Te-rich melt of Bi1.8Sb0.2Te3.0+delta. The composition profile was determined by electron probe microanalysis (EPMA) measurement to be homogeneous in the center part of the single crystalline ingots. An excess of Te is segregated at the top of the ingots. A high thermoelectric performance was achieved at low temperature in the p-type samples. The largest value of the Seebeck coefficient a of >500 muV K-1 was obtained at 200 K for delta = 0.259 to give ZT = 1.1. The optimum carrier concentration was determined to be n = 1.6 x 10(19) cm(-3) for the highest thermoelectric performance. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2003.08.066

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Er1-xYxCo10Mo2 (x = 0, 0.2, 0.4, 0.6, and 0.8) and ErCo10-yNiyMo2 (y = 0, 1, 2, and 3) compounds have been studied in magnetization and susceptibility measurements. Interesting magnetization curves at selected temperatures have been observed. The results show that both these systems undergo a spin reorientation of the axis-to-plane type (referred to decreasing temperature). The spin-reorientation temperature, T-SR, is found to decrease not only with increasing Y content in the Er1-xYxCo10Mo2 compounds but also with increasing Ni concentration in the ErCo10-yNiyMo2 compounds. The causes of the observed concentration dependence of TSR are discussed. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(03)00081-7

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Magnetization measurements and neutron diffraction have been performed on HoPdSn single crystals with the orthorhombic epsilon-TiNiSi-type structure. Two successive magnetic transitions have been found at T-t = 2.5 K and T-N = 3.6 K. Neutron-diffraction experiments on a single crystal of HoPdSn have revealed that there are two kinds of magnetic reflections which can be indexed with the propagation vectors k(1) = (1, 0, k(z)) and k(2) = (0.33,0,0.93). The k(2)-component of k(1) changes discontinuously from k(z) = 0.38 to 0.35 at T-t = 2.5 K, while for k(2) there is not such a change. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(02)01753-2

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Magnetic and transport properties of Ho7Rh3 Single crystals have been studied by measuring magnetization, magnetic susceptibility, electrical resistivity and by performing neutron-diffraction experiments. Ho7Rh3 has two magnetic transitions from paramagnetic to antiferromagnetic at T-N = 34K and from antiferromagnetic to ferrimagnetic at T-C = 22K. In the ferrimagnetic phase, a small spontaneous magnetization in the c-plane is observed. It is found by neutron-diffraction measurements that Ho7Rh3 has a modulated incommensurate helical magnetic structure with the propagation vector Q = (0, 0, 0.38) at 1.5 K. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(02)01738-6

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

The crystal structures of the α- and β-Zn4Sb3 have been investigated by the synchrotron-radiation X-ray powder diffraction at temperatures of 180 to 295 K. The Rietveld analysis indicates that the α-Zn4Sb3 possesses a rhombohedral structure with R-3c as the β-Zn4Sb3 does. The β- to α-phase structural transition is of 2nd order and accompanies the reduction in the c/a and increase in volume (Δa/a&gt
0 and Δc/c&lt
0). The atomic displacement parameters and bond distance are calculated.

DOI： 10.1109/ICT.2003.1287504

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The Hall effect has been measured on the alpha- and beta-phase of Zn4Sb3 bulk samples prepared by the gradient freeze and spark-plasma sintering methods in the temperature range from 78 to 300 K. The thermal variation of the carrier concentration and hole mobility has been discussed for these two samples. The thermoelectric and transport properties have also been compared with those of the samples synthesized by different methods.

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Neutron powder diffraction studies have been performed for the Heusler compound 'CoTiSn' prepared from stoichiometric amounts of the constituent elements and its nitrogenation products. The Rietveld refinement indicates that the 'CoTiSn' sample consists of three phases: Co+Ti+Sn-->0.69Co(1.50)TiSn+0.05Ti(6)Sn(5)+0.06sn. It is concluded that the stoichiometric compound CoTiSn is not synthesized but that Co1.50TiSn with a half-filled vacancy sublattice in the MgAgAs-type structure which has the XYZ configuration is formed. Nitrogen absorption is accompanied by the disproportionation of the 'CoTiSn' sample according to the following equation: 'CoTiSn' + 0.23N(2)-->0.50Co(1.92)=TiSn+0.47TiN+0.36Sn+0.04CoSn(2)+0.03Co(1.50)TiSn. It is revealed that nitrogen atoms react selectively with Ti atoms in the Co1.50TiSn and Ti6Sn5 compounds and that nitrogen-induced occupation of the vacancy site in Co1.50TiSn by Co atoms takes place during nitrogenation; Co-1.92-TiSn with the Cu2MnAl-type structure is formed. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0925-8388(02)00402-4

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The low temperature thermoelectric properties of Zn4Sb3 samples prepared by the gradient freeze (GF) method and sintering have been characterized. With decreasing temperature a dramatic rise in the thermal expansion is observed associated with the structural transition from beta- to alpha-phase; DeltaIII = 2.8 X 10(-4) at T-s(GF) = 257.4 K for GF and DeltaIII = 1.6 X 10(-4) at T-s(S) = 236.5 K for sintered samples. Enhancement is observed in electrical conductivity and p-type thermopower at T-s(GF) and T-s(S), while a reduction is observed in the magnetic susceptibility. The GF sample exhibits higher thermoelectric performance than the sintered sample. The power factor of the a-phase in the GF sample is twice as large as that of the beta-phase; it exceeds 20 muW/cm.K-2 between 120 and 240 K, indicating that the alpha-phase Zn4Sb3 is one of the prime candidates for thermoelectric materials for cryogenic use. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0925-8388(02)00113-5

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The magnetic and specific heat experiments have been performed on the orthorhombic PrNiSn and NdNiSn single crystals to explore the ground states and the role of the crystalline electric field (CEF) in the compounds. Anisotropic behaviors in the susceptibility are well accounted for by the CEF effect for both the compounds. The data for PrNiSn do not show any magnetic ordering down to 0.9 K and suggest a nonmagnetic singlet ground state. NdNiSn exhibits an antiferromagnetic order below T-N = 2.8 K. A sharp jump (12 J/mol K) in the specific heat near the TN confirms the bulk magnetic ordering. (C) 2002 Elsevier Science B.V. All rights reserved.

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We have examined the crystal structure of Ce(CuxGey)(2) compounds. The crystal structure of the system changes from the AlB2-type hexagonal structure to the ThSi2-type tetragonal structure with decreasing Cu:Ge ratio. It is revealed that the single phases of both the structures are only obtained in the narrow region of x + y = 0.95. Both structures have a random distribution of non-magnetic atoms. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(01)01299-6

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

The paper is devoted to the study of transport properties of semiconductor phase of iron disilicide (beta-FeSi2) at low temperature. The previous study of kinetic properties of beta-FeSi2 showed that there is very large difference in thermoelectric properties of a number of samples of the same composition prepared by the same method.
It was found no essential difference between electrical conductivity at low temperature of single crystals and that of polycrystalline samples of iron disilicide.
The paper shows that the smaller is the lattice parameters of sample the smaller is its electrical conductivity at similar to10 K. It is shown that the smallest electrical conductivity at this temperature corresponds to the unit cell of stoichiometric beta-FeSi2, or slightly smaller unit cell than stoichiometric one.
The study of specific heat and magnetic susceptibility of beta-FeSi2 at low temperature indicates no phase transition or magnetic ordering at T= 20-25 K corresponding to the break in temperature dependence of electrical conductivity.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

The low temperature thermoelectric properties have been investigated on Zn4Sb3 compound between 4 K and 300 K. A single phase Zn4Sb3 bulk crystal with the density of 95.4 % of the theoretical has been grown by a gradient freeze method. The resistivity exhibits a metallic conduction with an anomaly associated with a structural transformation from alpha to beta phase at T-S(GF) = 257.4 K. The thermopower is positive and larger in alpha than in beta phase. The elongation of Zn4Sb3 is small (1 X 10(-4)) at T-S(GF). The magnetic measurement shows that Zn4Sb3 is a diamagnetism and chi (T) curve has an appreciable increase at T-S(GF). The power factor of a phase is two times as large as that of beta phase at low-temperature region (below 300 K).

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Magnetic susceptibility and magnetization of Ce2CuSi3, single crystal show strong anisotropy. it is revealed that the magnetic susceptibility exhibits a maximum at 2K only along the hexagonal c-axis at low magnetic fields. The anisotropic magnetic properties are explained by crystalline electric field effect. The analysis of the magnetization curves indicates that magnetic ordering does not occur down to 1.8 K. Electrical resistivity behaves as a typical Kondo-lattice system with the crystalline electric field effect. (C) 3000 Elsevier Science B.V. Ail rights reserved.

DOI： 10.1016/S0921-4526(99)01086-8

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Neutron scattering experiments on the Kondo semiconductor CeNiSn were performed in a high-energy resolution condition using a low-background isotope sample. The pseudogap spectrum of an energy scale about 15 K is proved to exist in the magnetic excitation, which is in accord with bulk measurements. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)00810-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOC JAPAN  

Metamagnetic transitions in the intermetallic compound Nd7Ni3 have been studied by measuring magnetization, magnetic susceptibility, magnetostriction as well as by neutron diffraction experiments under external magnetic fields up to 10T. When the field is applied in the c-plane. there are three magnetic namely ferrimagnetic I, ferrimagnetic II and antiferromagnetic phases. In the ferrimagentic I phase, magnetic structure is conical with a basal plane helical component. In the ferrimagentic II phase: distorted helix structure is maintained. There are three metamagnetic transitions characterized by critical fields H-C1, H-C2 and H-C3. Along the c-axis, a conical structure exists between Te and TN. Two metamagnetic transitions characterized by H-C4 and N-C5 were observed. The critical field from ferrimagnetic II and antiferromagentic phase has a maximum near 18 K. Magnetic field (H)-temperature (T) phase diagrams for both field configurations are presented. A new magnetic or some another kind of phase has been found just above T-N.

DOI： 10.1143/JPSJ.69.1850

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Effect of pressure on the cubic to tetragonal structural transition temperature T-M has been investigated in RInAu2 (R = La, Ce, Pr and Nd) from the electrical resistivity measurements up to 24 kbar. The pressure dependence of T-M is given by T-M = A(P-c - P)(1/2) with P-c = 57.6, 34.3 and 14.0 kbar and the initial pressure derivative dT(M)/dP = - 1.9, - 2.1 and - 2.7 K/kbar for R = Ce, Pr and Nd, respectively. The existence of the Kondo effect is elucidated in both cubic and tetragonal phases of CeInAu2 by the application of pressure. In NdInAu2 the tetragonal phase is totally suppressed by pressure and a new pressure-induced phase transition appears at 3 K. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)01083-2

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Hydrostatic pressure dependence measurements of the electrical resistivity of YbInAu2 and LuInAu2 up to 21 kbar indicate the decrease of the magnetic resistivity maximum temperature T-max and the increase of the coefficient c in - In T term as the pressure increases. Opposite response of T-max and c against pressure is explained by the consequence of increasing the exchange coupling between 4f and conduction electrons and decreasing n(E-F). The pressure dependence of the residual resistivity is compared with the previous quasi-hydrostatic experiment. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)01081-9

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CePt2Sn2 has the tetragonal P4/nmm structure. Polycrystalline (pcr) material possesses in addition a small monoclinic distortion and shows a magnetic transition below 1 K, while no such transition is seen in purely tetragonal single-crystalline (scr) samples. Our mu SR, specific heat and magnetization data are consistent with a spin-glass-like (sgl) state below 0.45 K in scr and long-range order (lro) below 0.85 K in per samples. mu SR demonstrates clearly that the Ce3+ spin ensemble remains dynamic down to lowest temperatures (0.02 K) in the sgl state. but reaches the usual quasi-static limit in the lro state. These results are discussed in terms of geometrical magnetic frustration. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)01203-X

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The effect of doping in CeNiSn has been studied by the measurements of electrical resistivity, Hall coefficient and magnetic susceptibility for single crystals of CeNi1-xTxSn (T=Co, Cu, and Pt) and Ce1-yLayNiSn (x,y = 0.01 and 0.05). All these impurities are found to increase the residual resistivity by several times up to 1 mΩ cm for x or y = 0.01, while for x or y = 0.05 the resistivities along the orthorhombic b and c axes saturate to values smaller than those for 0.01. Furthermore, the low-temperature increase in the Hall mobility of CeNiSn was found to be strongly suppressed in a similar way by all the impurities. These results indicate that residual carriers in CeNiSn with an anisotropic gap are immobilized by any impurity substituted either in the 4f site or the non-4f site. © 1999 The American Physical Society.

DOI： 10.1103/PhysRevB.59.13878

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The electronic ground state of CeNiSn has been investigated by means of specific-heat measurements below 2 K in magnetic field up to 5 T using a high-quality single crystal. Unusual temperature and field dependence of specific heat reveals that the density of states of CeNiSn has a peak at EF inside the pseudogap. We claim that CeNiSn is no longer a Kondo insulator but a metal at the lowest temperature. ©1999 The American Physical Society.

DOI： 10.1103/PhysRevB.59.2599

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The specific heat of several CeNiSn single crystals of various purity has been measured in the temperature range from 25 mK to 5 K and in magnetic fields from zero to 7 Tesla. At very low temperatures (below ∼200 mK) the specific heat is found to vary linearly with temperature (C = γT), the coefficient y decreasing with increasing purity. Above 200 mK, the specific heat is well described as the sum of a linear and a quadratic term. An applied magnetic field affects mostly the linear term, which first slightly decreases, then strongly increases with field. In magnetic fields, a nuclear hyperfine specific heat contribution is superimposed, which is due mostly to the bare Zeeman-splitting of the 115Sn, 117Sn, 119Sn nuclei (all with spin I = 1/2 and with abundances of 0.35, 7.61, and 8.58% respectively) in the externally applied field. The results on the specific heat at very low temperatures in applied fields fit into the model of an enhanced (heavy-fermion type) density of states which is modified by coherent antiferromagnetic fluctuations into a V-shaped density of states at the Fermi energy.

DOI： 10.1023/A:1021883621341

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER PHYSICAL SOC  

The effect of doping in CeNiSn has been studied by the measurements of electrical resistivity, Hall coefficient and magnetic susceptibility for single crystals of CeNi1-xTxSn (T = Co, Cu, and Pt) and Ce1-yLayNiSn (x,y = 0.01 and 0.05). All these impurities are found to increase the residual resistivity by several times up to 1 m Omega cm for x or y = 0.01, while for x or y = 0.05 the resistivities along the orthorhombic b and c axes saturate to values smaller than those for 0.01. Further, the low-temperature increase in the Hall mobility of CeNiSn was found to be strongly suppressed in a similar way by all the impurities. These results indicate that residual carriers in CeNiSn with an anisotropic gap are immobilized by any impurity substituted either in the 4f site or the non-4f site. [S0163-1829(99)04121-1].

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Japanese Journal of Applied Physics  

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The electronic ground state of CeNiSn has been investigated by means of specific-heat measurements below 2 K in magnetic field up to 5 T using a high-quality single crystal. Unusual temperature and field dependence of specific heat reveals that the density of states of CeNiSn has a peak at E-F inside the pseudogap. We claim that CeNiSn is no longer a Kondo insulator but a metal at the lowest temperature. [S0163-1829(99)01204-7].

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN J APPLIED PHYSICS  

Gas-phase nitrogenation of CoTiSn compound with the MgAgAs-type structure has been examined by means of x-ray diffraction (XRD) and x-ray absorption fine structure (XAFS). The XRD suggests that the nitrogenation product is composed of the corresponding Cu2MnAl-type compound with expanded unit-cell volume comparable to that of Co2TiSn and subtle trace of Ti6Sn5 and Sn. Whereas the x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectra for the Ti, Co and Sn K-edges clearly indicate the coexistence of TiN and Co1+yTiSn phases in the product. It is also revealed that more Co atoms than expected from the chemical formulas are introduced into the vacancy site of the MgAgAs structure in Co1+yTiSn with 0 less than or equal to y less than or equal to 0.4.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Science Ltd  

Neutron diffraction experiments were carried out to determine the magnetic structure of Nd7Ni3 in an external field. At 4.2 K and in external fields below 1.3 T the magnetic structure is conical with a basal plane helical component having a propagation vector Q = (0, 0, 1/3) and a c-axis ferromagnetic component. Above 1.3 T the c-axis component disappears, while the basal plane component remains up to 2.7 T. Below 0.3 T, the magnetic structure changes from conical to helical at about 8 K. A rough (H, T) phase diagram is given and is generally consistent with the results of magnetization measurements.

DOI： 10.1016/S0022-3697(99)00086-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

We have measured the thermal conductivity and thermoelectric power of YbAu2 and YbAu3. Both compounds are characterized as an antiferromagnetic Kondo lattice compound. We found that the temperature dependence of thermal conductivity is well explained by assuming the Wiedemann-Franz law. This fact suggests that electronic contribution is dominant and the same carriers are responsible for both thermal and electrical transport. Thermoelectric power shows complicated temperature dependence with plural peak structures and sign reversal at low temperature. This behavior is characteristic of Kondo lattice system and is explained by the competition between Kondo effect and antiferromagnetic interaction. © 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)01042-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOC JAPAN  

High-field longitudinal magnetoresistance and magnetization measurements up to 36 T have been carried out on a single crystal CeNiSn which shows metallic behavior in the resistivity along the a-axis. Large negative magnetoresistances are found along the a-, b- and c-axes in high fields above 10 T as previously reported in a semiconducting sample. A metamagnetic behaviour in the magnetization is observed along the a-axis at around 15 T. The linear field dependence of log rho(H) indicates that the Zeeman energy of the 4f-electron moment quenches the pseudo energy gap on the Fermi surface in CeNiSn.

DOI： 10.1143/JPSJ.67.2455

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Kondo semiconductors are a class of strongly correlated f-electron materials whose low-energy excitations exhibit a (pseudo)gap at low temperatures. The significant difference between the pseudogap in orthorhombic CeNiSn and CeRhSb and the real gap in cubic Ce(3)Bi(4)Pt(3) and YbB(12) is highlighted by a comparison of transport properties. Low-temperature measurements of the magnetoresistance, Hall coefficient and specific heat of CeNiSn have revealed a field-induced excitation of the coherent low-carrier state. A systematic study of CeNi(1-x)T(x)Sn (T = Co, Cu and Pt) has shown that the residual carriers in CeNiSn are immobilized by 1% substitution irrespective of the substitutes. Further substitution with 5% Cu induces a magnetic instability at T = 0. (C) 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(97)00842-1

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The electrical resistivity has been studied in the Heusler alloy system CeIn(Cu1-xAgx)(2) under pressure up to 20 kbar. Under pressure, the Neel temperature, T-N, decreases for x = 0.75 and 0.85 but increases for x = 0.50. T-max (resistivity maximum temperature) decreases for x = 0.50 and 0.75 while for x = 0.85 it increases above 10 kbar. These results are analyzed and discussed according to Doniach's Kondo-necklace model. The result shows that the system approaches to the pure heavy-fermion state (for x = 0.75 and 0.85) while it approaches to the manifested antiferromagnetic state (for x = 0.50) due to the pressure-induced hybridization. (C) 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(97)00604-5

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Specific heat measurements have been performed below 2 K in magnetic field up to 5 T using high-quality single-crystalline CeNiSn which shows metallic conduction at low temperatures. Remarkable field dependence has been observed in the specific heat, suggesting the possibility that a new electronic ground state due to a many-body effect is realized in CeNiSn below 0.5 K. © 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(97)00408-3

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The electrical resistivity of TbNiSn for the b-axis has been measured under hydrostatic pressures up to 22 kbar. Resistivity anomalies associated with the successive magnetic transitions are observed. At P=0 kbar, the transitions at TN (=18.5 K) and T3 (=7.6 K) are second order whereas the transition at T2 (=6.0 K) is first order. We observe that the resistivity drops discontinuously at T2 and accompanies thermal hysteresis. There is not appreciable change in the resistivity at T1 (=2.2 K). The pressure-temperature magnetic phase diagram has been constructed. All the transition temperatures first decrease, take minima at 3 kbar and then increase with increasing pressure. It should be also noted that the T3 line is merged in the T2 line above 17 kbar. Total spin disorder resistivity is pressure independent, [resistivity, rare earth compound, TbNiSn, phase diagram, magnetism]. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.

DOI： 10.4131/jshpreview.7.550

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We report on the electrical resistivity of YbAu2 and YbAu3 under hydrostatic pressures up to 20 kbar. It is revealed that YbAu2 is a Kondo-lattice compound with the characteristic temperature of the order of 10 K. Both the coefficient of -ln T and the temperature where resistivity has a minimum are decreased by application of pressure. These results suggest that Kondo effect is suppressed by application of pressure. On the other hand, resistivity of YbAu3 is hardly affected by pressure. This implies that the 4f electronic state in YbAu3 is rather stable against lattice compression. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.

DOI： 10.4131/jshpreview.7.602

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The AC magnetic susceptibility for itinerant ferromagnet TiCoSn has been investigated at temperatures between 80 K and 300 K under hydrostatic pressures up to 18 kbar. The Curie temperature is increased linearly with increasing pressure at a rate of dTc/dp=+0.12 K/kbar. This value is one order of magnitude smaller than that of TiCo2Z (Z=Al, Ga and Sn). Below Tc, the absolute value of susceptibility is reduced by applying pressure. Therefore, it is suggested that the effect of pressure on magnetic interaction is weak in TiCoSn, and then this can be interpreted in terms of Co-Co spacing in the compounds. [Heusler compound, AC susceptibility, the Curie temperature, Co-Co spacing, hydrostatic pressure]. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.

DOI： 10.4131/jshpreview.7.553

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMERICAN PHYSICAL SOC  

We measured the temperature dependence of the surface impedance Z(s) = R-s + iX(s) at 9.6 and 14 GHz in a single crystal of the Kondo lattice compound CeNiSn, from which microwave complex conductivity sigma(T) = sigma(1)(T) - i sigma(2)(T) was determined. Below about 10 K the imaginary part sigma(2) increases rapidly and the real part sigma(1) is much lower than the de conductivity. These results indicate a rapid decrease in the scattering rate of the quasiparticles, whose excitation spectrum is drastically changed with the coherence gap formation at low temperatures.

DOI： 10.1103/PhysRevB.56.8277

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We have measured the thermal conductivity kappa for CeNiSn, CeNi0.95CeNi0.05Sn (M=Co,Cu), and CeRhSb single crystals. The pronounced enhancement of kappa along the b axis is observed around 5 and 10 K in CeNiSn and CeRhSb, respectively. In CeNiSn, this enhancement is almost completely suppressed either by application of magnetic field of 15 T along the a axis, which is the easy axis of magnetization, or by the substitution of 5% Co and Cu for Ni. These results indicate that the enhancement of K along the b axis originates from the opening of the pseudogap in these compounds. On the other hand, the enhancement of K along the a axis in CeNiSn and those along the a and c axis in CeRhSb are much smaller than that along the b axis. These anisotropic behaviors in K reflect the anisotropy of the gap in these compounds.

DOI： 10.1103/PhysRevB.55.6421

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We have used inelastic neutron scattering to determine the spin dynamics in the Kondo insulator CeNiSn under magnetic fields up to 10 T applied parallel to the easy a axis. The well known excitations peaked at ℏω = 2 meV located at the Brillouin zone centre and at ℏω = 4 meV located at the Brillouin zone border were studied comparatively. At the scattering vectors (010) and (001) the peak shifts continuously from 2 to 2.5 meV with the field. No Zeeman splitting could be detected at the accuracy of our measurements. For the '4 meV' excitation studied at the scattering vector (00.51), a field as large as 10 T begins to fill in the gap whereas there is no appreciable change in the spin dynamics between 0 and 6 T. The main feature is the broadening of the response. We compare our experimental results to recent theoretical developments.

DOI： 10.1088/0953-8984/9/7/021

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The development of magnetic correlations at low temperatures was studied by muon spin relaxation (mu SR) and specific heat measurements in CePtxNi1-xSn (x = 0.12, 0.2) and CeCuxNi1-xSn (x = 0.05, 0.1, 0.2). Doping with Pt up to 20% increases the magnetic correlations only weakly. In contrast, doping with either 10% or 20% Cu strengthens the correlations up to the point of forming a spin-glass-like state and finally long range order. The large difference in magnetic behavior between CePtxNi1-xSn and CeCuxNi1-xSn shows that the increase in d electron density when doping with Cu is likely to be the important factor for strengthening magnetism.

DOI： 10.1016/S0921-4526(97)81591-8

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We present results of the magnetic susceptibility chi(T), electrical resistivity rho(T) and Hall coefficient R-H(T) for CeNi1-xTxSn (T = Co and Cu, 0 less than or equal to x less than or equal to 0.05). Co impurities decrease chi along all the principal axes, whereas Cu impurities increase. Both impurities at x = 0.01 cause a remarkable increase in rho at 1.4 K with 970 mu Omega cm/at% Cu at maximum. For x = 0.05, rho(T) is saturated to a lower value than that for x = 0.01. R-H(T) for x = 0.01 Co and Cu becomes negative below about 4 K and the absolute value is smaller than that for x = 0, while R-H for x = 0.05 remains positive down to 1.6 K. The nonmonotonic dependence of rho(T) and R-H(T) on x indicates extremely strong scattering of quasiparticles from nonmagnetic impurities in the presence of pseudogap.

DOI： 10.1016/S0921-4526(97)81593-1

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We report specific heat of high-quality single-crystalline CeNiSn in magnetic field mu(0)H up to 14T. Significant field dependence of specific heat was clearly observed in a temperature range from 2 to 25 K. The effect of magnetic field in CeNiSn is discussed in terms of a pseudo-gap around the Fermi level with the Zeeman energy.

DOI： 10.1016/S0921-4526(96)00785-5

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We have measured the magnetoresistance at high fields up to 15 T and at low temperatures down to 0.4 K for CeNiSn with the orthorhombic structure. The longitudinal magnetoresistance (J parallel to H) is small in magnitude for the magnetic field H parallel to b- and c-axis. On the other hand, the positive magnetoresistance is found to become dominant with the decrease of temperature for H parallel to b- and c-axis in the transverse configuration (J perpendicular to H). For H parallel to a, the magnetoresistance is negative for any current direction. These experimental results have been discussed on the basis of the cyclotron motion of the compensated carriers with closed Fermi surfaces and the reduction of the anisotropic hybridization gap.

DOI： 10.1016/S0921-4526(96)00804-6

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The magnetic excitation spectrum of CeNiSn has been studied by inelastic neutron scattering under high magnetic field up to 10 T. The well known modes of characteristic energies 2 and 4 meV were studied. No Zeeman splitting was observed for either of them. The mode initially peaked at 2 meV shifts continuously to higher energy. The characteristic feature of the 4 meV mode is the broadening observed for the highest applied held of 10 T whereas there is no appreciable change in the spin dynamics between 0 and 6T.

DOI： 10.1016/S0921-4526(96)00784-3

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Effects of pressure and impurities on the magnetic excitation peak at ℏω = 4 meV are studied by neutron scattering on CeNiSn. The high pressure remarkably affects the magnetic excitation: at P = 6kbar the excitation shifts to a higher energy region; at P = 11 kbar the excitation peak disappears below 7 meV. The increase of the peak energy at 6kbar is consistent with the explanation by the particle-hole excitation over the hybridization gap. The sample quality, metallic or semiconducting, has no effect on the magnetic excitation spectrum.

DOI： 10.1016/S0921-4526(96)00781-8

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Recent results of thermodynamic and transport measurements on CeNiSn at low temperatures show a strong dependence on sample purity. A lower impurity content leads to a more metallic behavior of CeNiSn. We present muon spin relaxation (mu SR) spectra at T < 1K for two samples of CeNiSn which show quite different behavior in low temperature specific heat. No significant difference could be detected in decisive mu SR parameters for the two specimen. This strengthens the view that mu SR probes the intrinsic magnetic properties of the heavy fermion ground state of CeNiSn.

DOI： 10.1016/S0921-4526(96)00780-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BALTZER SCI PUBL BV  

We present zero and longitudinal field mu SR measurements of single crystal and polycrystalline specimens of the heavy fermion compound CePt2Sn2. Above 1 K the behaviour of the two samples is indistinguishable; the muon 1/T-1 increases with decreasing temperature until 25 K when it plateaus. The 1/T-1 relaxation rate differs strongly for the two cases below similar to 0.8 K. At 0.1 K a rate of about 20 mu s(-1) is seen in the polycrystal while in the single crystal it is only about 5 mu s(-1) Even more revealing is the fact that longitudinal field decoupling spectra at very low temperatures demonstrate an essentially static spin system to be present in the polycrystalline material while the single crystal shows definite dynamic spin properties. We conclude that, in the presence of the distortion, long range magnetic order occurs below 0.9 K while in tetragonal symmetry long range order is suppressed (probably due to frustration) and spin fluctuations remain for T --> 0.

DOI： 10.1023/A:1012683911592

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Powder neutron diffraction on the hexagonal compound Nd7Ni3 have been performed from 35 to 1.7 K. The magnetic structure is conical at 1.7 K, with a basal plane helix with propagation vector k = (0, 0,1/3), and a c-axis ferromagnetic component. Above 8 K, the c-axis ferromagnetic component disappears, while the basal plane helical component remains up to the Neel temperature at 25 K. The propagation vector changes from k = (0, 0, 1/3) at 1.7 K to k = (0, 0, 0.257) at 20 K through a two-phase state with k = (0, 0, 0.286) and k = (0, 0, 0.314) at 7.25 K. © 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(97)00710-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BALTZER SCI PUBL BV  

The temperature dependence of the muon spin relaxation rate lambda was measured in two samples of CeNiSn with markedly different impurity content and in the quasi-ternary compounds CePtxNi1-xSn (x = 0.12, 0.2) and CeCuxNi1-xSn (x = 0.05, 0.1, 0.2) in order to study the development of magnetic correlations. No significant change in lambda was found for the two samples of CeNiSn although their low temperature specific heat differs strongly. Hence mu SR probes the intrinsic magnetic properties of the spin-liquid state of CeNiSn. Replacing Ni with up to 20% Pt results only in minor changes of lambda. In contrast, a strong effect is seen when Ni is replaced by Cu. Already at 10% Cu the system forms a spin-glass-like state below 0.9 K. At 20% Cu this behavior is strengthened, but antiferromagnetic order of the type seen in CePtSn or CePdSn is not reached. The results show further that the change in 4f hybridization initiated by volume expansion in the alloyed samples is not the dominating mechanism strengthening the magnetic correlations. Decisive is the increase in d electron density when replacing Ni by Cu.

DOI： 10.1023/A:1012619624796

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The magnetization and longitudinal magnetoresistance measurements up to 36 T have been carried out on a single-crystal CeNiSn which shows metallic behavior in the resistivity along the a-axis. Large negative magnetoresistances are found along the a-, b- and c-axis in high fields above 10 T. A metamagnetic behavior in the magnetization is observed along the a-axis at around 15T and a precursor along the b-axis at around 35 T.

DOI： 10.1016/S0921-4526(96)00801-0

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Language：Japanese   Publisher：広島大学  

1.序論 近年,希土類元素のセリウム(Ce),サマリウム(Sm),イッテルビウム(Yb)などを含む金属間化合物の研究が盛んに行われている。これらの化合物は,希土類の4f電子と配位子の伝導電子との混成に依って,価数揺動状態や重い電子状態などの特異な物性を示す事が知られている。また,これらは磁性元素である希土類イオンが格子を組んでいるにも拘わらず近藤効果を示すので近藤格子化合物と呼ばれる。近藤格子系は基底状態で,増強されたパウリ常磁性,弱い反強磁性,非BCS超伝導,或いはそれらが共存した状態を示す[1]。本研究で取り上げたCeNiSnは,低温で電気抵抗が増大するCe化合物として初めて見い出された物質である[2]。これまでにも半導体的性質を示す希土類化合物としてSmB_6やYb_12などが知られていたが,CeNiSnの発見により近藤格子系におけるエネルギーギャップ形成の問題が改めて見直され,実験と理論の両面から盛んに研究される様になった。半導体的Ce化合物として,CeNiSnに続いてCe_3Bi_4Pt_3[3]とCeRhSb[4]が見い出され,それらは,近藤半導体或いは近藤絶縁体と呼ばれる様になった。近藤半導体のエネルギーギャップは,電子相関の強い4f電子が関与した多体効果に依って生じる為に,その大きさは約100Kと小さく,しかも温度上昇とともに消滅する。この点が古典的半導体のSiやGeにおける1eV程度のバンドギャップとは異なり新しい。これまでの研究結果から,CeNiSnのエネルギーギャップ形成について以下の様な知見が得られていた[5]。電気抵抗,ホール効果,比熱,核磁気共鳴(NMR),トンネル分光の実験から,10K以下の低温でCeの4f電子と配位子の伝導電子が混成してできた重い準粒子バンドの中に10K程度のV字型のエネルギーギャップが形成される事が明らかになった。更にCeサイトとNiサイトの置換効果の研究からは,ギャップ形成には格子の周期性に基づくコヒーレンスの発達が重要である事が判ってきた。この様な実験的研究の進展は,近藤格子系におけるギャップ形成についての理論的研究を促した。しかし,重要な問題点も数多く残されている。一つは結晶に含まれる微量不純物の効果である。CeNiSnのエネルギーギャップは10K程度と小さい為に不純物の影響を強く受ける事が予想される。0.1Kまでの比熱とNMRの結果は,ギャップが形成された後もV字型ギャップの底に有限の状態密度が存在する事を示している。第二はギャップの異方性である。比熱とNMRの結果から提案されたV字型状態密度は,エネルギーギャップが異方的で,ある方向で閉じている事を強く示唆する。本研究では,近藤半導体CeNiSnの本質的な物性を明らかにする事を目的とした。この為に,CeNiSn純良単結晶を作製し,その電気抵抗,磁気抵抗,比熱の測定を行った。2.単結晶育成 CeNiSn単結晶は高周波炉とアーク炉を用いたチョコラルスキー法及び赤外線加熱炉を用いた浮遊帯域溶融法により作製した[6]。表1に結晶育成の詳細を示す。電子プローブミクロ分析による組成分析の結果,結晶の組成は原料仕込み比に依存せず1%以内の誤差で1 : 1 : 1になっている事が判った。不純物相としてCe_2O_3,CeNi_2Sn_2,Ce_2Ni_3Sn_2がそれぞれ5×5μm^2,20×5μm^2,50×2μm^2程度の大きさで結晶中に分散している。これらの内,Ce_2O_3とCeNi_2Sn_2は,結晶育成炉の真空度を良くした上で炉内を空焼し雰囲気を改善した結果,#4以降の結晶では検出限界以下に減少した。それでも残留するCeNi_2Sn_2は,更に固相電解法による純良化処理を施す事に依って#5と#8では0.1%以下に滅少した。

DOI： 10.15027/698

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Language：English   Publisher：The Physical Society of Japan (JPS)  

Specific heat of single crystal of CeNiSn has been measured between 1.3 and 60 K and analyzed together with that of polycrystals of CeRhSb, CeNi1-xPtxSn (x = 0.03, 0.06, 0.12 and 0.20) and CeNi1-yCoySn (y = 0.03 and 0.10). The magnetic specific heat divided by temperature Cm/T of CeNiSn and CeRhSb exhibits a maximum and substantially decreases at low temperatures indicating the energy gap opening in the heavy quasiparticle band. The Kondo temperatures TK were estimated to be 51 K for CeNiSn and 89 K for CeRhSb by fitting the magnetic entropy Sm. Using the reduced temperature T̃ = T/Tk, Cm/T was plotted in Cm/T̃ versus T̃. The plot reveals the obvious relation between the energy gap formation and the Kondo effect.

DOI： 10.1143/JPSJ.65.2614

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physical Society  

CeNiSnの119Sn核のスピン-格子緩和時間T1が，0.2から8Tの磁場もとで20mKまでの低温領域で測定された．1K以下では(T1T)=一定の振舞いが見られ，V字型ギャップ内の残留状態密度の存在を示している．磁場中での(T1T)-1の値は2Tまではほぼ一定であるが，2T以上では磁場に比例して(T1T)-1の値は増大する．こうした(T1T)-1の磁場依存性は外部磁場によるフェルミ面付近でのV字型ギャップのシフトにより説明される．

DOI： 10.1103/PhysRevB.54.6062

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMERICAN PHYSICAL SOC  

The magnetic field dependence of the spin-lattice relaxation rate 1/T-1 of Sn-119 in CeNiSn has been measured down to 20 mK in a field range of 0.2-8 T. (T1T)(-1) is constant below 1 K, which depends on the external field in such a manner that its value stays constant to 2 T, while it increases linearly with the field up to 8 T. It is shown that this magnetic field dependence of (T1T)(-1) is well explained by the simple scenario that the quasiparticle density of states at the Fermi level is produced by the Zeeman splitting of the up- and down-spin bands, keeping its V-shaped gapped structure unchanged for fields less than 8 T. The present experiment has elucidated that CeNiSn is in a semimetallic ground state with a low carrier density and the application of a magnetic field exceeding 2 T turns out to supply effective carriers.

DOI： 10.1103/PhysRevB.54.6062

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Muon spin-rotation-relaxation (mu SR) experiments were performed at low temperature in transverse, zero and longitudinal field on Ce0.85La0.15NiSn, CePt0.12Ni0.88Sn, CePt0.2Ni0.8Sn and CeCu0.1Ni0.9Sn as an extension of our previous studies of the CeTSn (T = Ni, Pt, Pd) series. In CeNiSn we have proven the formation of weakly dynamic paramagnetic spin correlations, below 1 K which, however, do not lead to long-range magnetic order even at T = 10 mK. For Ce0.85La0.15NiSn the predicted heavy-hole gas antiferromagnetism is not seen, but rather a reduction of magnetic correlations. Both Pt-doped compounds exhibit no significant enhancement of spin correlations although CePtSn is an antiferromagnet with T-N approximate to 7 K. The magnetic correlations increase strongly for CeCu0.1Ni0.9Sn up to the point of forming a spin-glass-like state at T < 0.9 K. Doping with either 20% Pt or 10% Cu increases the unit cell volume by roughly 1%. Volume expansion in CeTSn is a known cause for a reduction of the hybridization between f electron states and conduction electrons, thereby strengthening magnetic interactions. Yet, the marked differences in magnetic behaviour between replacing Ni in part by either isoelectronic Pt or by Cu, which has two more d electrons, indicates that the dominating effect must be the increase of the d electron density instead.

DOI： 10.1088/0953-8984/8/37/018

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Magnetic excitation spectra in CeNi1-xCoxSn (x = 0, 0.1) have been studied by single-crystal neutron scattering. The inelastic peak at ℏω = 4 meV and Q = (Qa, 1/2 + n, Qc), which was observed in CeNiSn so far, was found to be suppressed, but could be detected in CeNi0.9Co0.1Sn. This suggests that the corresponding dynamic antiferromagnetic correlation still remains in the gap-suppressed Co-substituted sample.

DOI： 10.1016/0921-4526(96)00141-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We have found that the semiconductor-like increase in resistivity previously reported on CeNiSn and CeRhSb below about 8 K is suppressed with decreasing impurity concentration in single-crystalline samples. Nevertheless, the absolute values of the Hall coefficient strongly increase as temperature decreases. Therefore, we interpret the metallic behavior found in the a-axis resistivity of a purified crystal of CeNiSn as a consequence of the significant increase of relaxation time of carriers. Even for the purified crystal, the residual gamma value is 40 mJ/K(2) mol at 0.03 K. These results suggest that the energy gap is closed along the a-axis and that residual carriers are strongly localized in the presence of impurities.

DOI： 10.1016/0921-4526(96)00137-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMERICAN PHYSICAL SOC  

Measurements of Sn-119 nuclear spin-lattice relaxation rate, 1/T-1, and Knight shift, K, in the off-stoichiometric compound CeNi1.01Sn and the substituted compounds CeNi(1-x)M(x)Sn (M=Cu,Co) and Ce1-xLaxNiSn have been made in order to unravel the impurity and/or carrier doping effects on the V-shaped gapped state in CeNiSn. From the detailed analysis of the T dependence of 1/T-1, it is shown that the density of states (DOS) is induced just at the Fermi level for CeNi1.01Sn, whereas the DOS increases progressively with the dopant in a finite-energy range near the Fermi level for the substituted compounds. The respective substitution of Co and La into Ni and Ce sites changes the gapped state into the nonmagnetic Fermi-liquid state, whereas the replacement of Ni by Cu with x> 0.06 gives rise to the antiferromagnetic (AF) ground state. It is suggested that the AF order is realized by the combined effect of the rapid collapse of the V-shaped gap and the increase of the DOS at the Fermi level. It has been found to lead to the magnetic ground state and the nonmagnetic Fermi-liquid state to dope electrons and holes into the renormalized conduction bands, respectively.

DOI： 10.1103/PhysRevB.53.6385

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Millimetre wave magnetotransmission measurements are used to provide the first clear evidence for magnetic defects in CeNiSn. At least two defect configurations are observed, both probably involving Ce3+ ions.

DOI： 10.1016/0921-4526(95)00509-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physical Society of Japan  

We have measured the magnetoresistance of the orthorhombic CeNiSn at high fields up to 15 T and at low temperatures down to 0.4 K. The positive magnetoresistance is found to become dominant with the decrease of temperature for the magnetic field H applied along the b- and c-axes in the transverse configuration between the current J and the field H (J ⊥ H). On the other hand, the longitudinal magnetoresistance (J ∥ H) is small in magnitude for H ∥ b and c. For H ∥ a, the magnetoresistance is negative for any current direction. These experimental results have been discussed on the basis of the cyclotron motion of the compensated carriers with closed Fermi surfaces and the reduction of the anisotropic hybridization gap.

DOI： 10.1143/JPSJ.65.1158

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physical Society of Japan  

The effect of magnetic field on the electronic ground state in CeNiSn has been investigated by means of specific-heat measurement in magnetic fields μ0H up to 14 T. A high-quality single crystal allows us to observe a marked field effect on specific heat in the temperature range from 2 to 25 K. The ground state is discussed in terms of a pseudo-gapped density of states in the Kondo resonance band with residual states at the Fermi level inducing the Zeeman splitting.

DOI： 10.1143/JPSJ.65.3119

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CZECHOSLOVAK JNL OF PHYSICS  

The temperature dependence of the microwave complex conductivity sigma(T) = sigma(1)(T) - i sigma(2)(T) was determined at 9.6 and 14 GHz in a single crystal of CeNiSn from the surface impedance measurements. Below about 10 K the real part sigma(1) is suppressed in comparison with the de conductivity and the imaginary part sigma(2) increases rapidly. These results indicate a rapid decrease of scattering of quasiparticles, whose excitation spectrum is drastically changed from the heavy-fermion to a gapped state at low temperatures.

DOI： 10.1007/BF02570992

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOC JAPAN  

Several single crystals of CeNiSn and CeNi0.95T0.05 Sn (T = Co and Cu) were grown and characterized by metallographic examination, electron-probe microanalysis and the measurements of resistivity, magnetoresistance, magnetic susceptibility and specific heat. Below 10 K, the semiconductor-like behavior found for dirty or substituted crystals is suppressed with decreasing impurities. For a crystal purified by the solid-state electrotransport technique, the resistivity along the orthorhombic a axis is metallic with the T-2 dependence, whereas those along the b and c axes increase below 3 K and pass through weak maxima at 0.8 K. These results suggest that the ground state of CeNiSn is not semiconducting but semimetallic with a pseudogap which closes along the a axis.

DOI： 10.1143/JPSJ.64.4834

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The gapped state in Kondo semiconductors CeNiSn and CeRhSb has been investigated by measurements of nuclear-spin lattice relaxation rate, 1/T-1 of Sn-119 and Sb-123 and Knight shift of Sn-119 and Sb-123. The T-dependences of T-1 and the shift in both compounds have revealed a novel feature for the gap state at low-T. Especially, the former has established that the energy gap is of a pseudo type with a V-shaped structure, where the band width, D and the pseudogap, Delta were estimated to be D = 140 and 210 K and Delta = 14 and 28 K for CeNiSn and CeRhSb, respectively. At very low-T, the T1T= constant behavior has, however, been found in both compounds. The fact that the T1T= constant behavior appears from much higher-T in CeNi1.01Sn and CeNi0.97Co0.03Sn suggest that impurities and/or imperfections yield a finite density of states at the Fermi level. Together with the Knight shift result, we highlight that the gapped state in Ce-based compounds belongs to a different class from the activated-type gap state in such as SmB6 and YbB12.

DOI： 10.1016/0921-4526(94)00598-P

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The heavy fermion compound CePt2Sn2 is characterized by an enormous linear specific heat coefficient gamma > 3J/mol K-2. Through longitudinal field measurements of the muon 1/T-1 relaxation rate, we were able to allow the formation of the heavy fermion state. We estimated a coherence temperature of similar to 20 K. Below 1 K, the electronic moments slowed down, however, static magnetic order was not observed above 20 mK; instead clear evidence was found for the presence of slow spin fluctuations down to our lowest attainable temperatures.

DOI： 10.1016/0921-4526(94)00414-Q

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We report on the measurements of resistivity, magnetoresistance, thermopower and specific heat on several single crystals of CeNiSn. As impurities of CeNi2Sn2 and Ce oxide increase up to about 3%, both the anisotropy and coherence in transport properties are smeared out. The increase in resistivity below 10 K is stronger for less pure crystal, which suggests strong localization of residual carriers in the pseudogap.

DOI： 10.1016/0921-4526(94)00602-R

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We performed muon spin rotation/relaxation (mu SR) studies on polycrystalline and single crystalline samples of CeNiSn. The system appears to be a dense system of weak magnetic moments with no evidence for static magnetic order down to 11 mK, the lowest temperature studied. In contrast, the spin system retains slow dynamics; it fluctuates at a rate of similar to 10(-7) s at the base temperature. These remaining fluctuations may be related to the absence of long range magnetic order. Results for polycrystalline Ce0.85La0.15NiSn show even weaker magnetic effects than those in pure CeNiSn, negating the notion that a partial replacement of Ce by La leads to enhanced magnetism and even magnetic order.

DOI： 10.1016/0921-4526(94)00591-I

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Six elastic constants Cii of orthorhombic CePtSn were measured between 1.8 and 300 K by an ultrasonic technique. The crystalline electric field (CEF) parameters were determined from the elastic softening due to the CEF effect. Anisotropic elastic anomalies around the successive magnetic transitions well reflect the subtle change in the spin configuration. © 1995.

DOI： 10.1016/0304-8853(94)00935-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Baltzer Science Publishers, Baarn/Kluwer Academic Publishers  

Zero-, longitudinal and transverse μSR measurements are reported on CeNiSn, CePdSn and CePtSn. Below 1 K CeNiSn exhibits strong magnetic correlations, up to possible short range order, but a magnetic phase transition did not occur down to 0.033 K. CePdSn and CePtSn signal their transition into the ordered antiferromagnetic phase by a spontaneous spin precession signal. The second magnetic phase transition in CePtSn reveals itself by the onset of a more complex spin precession pattern. Most unusual is the formation of a paramagnetic state with frozen random spin structure in CePtSn about one Kelvin above TN. © 1994 J.C. Baltzer AG, Science Publishers.

DOI： 10.1007/BF02069452

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CeNiSn and CeRhSb are Kondo-lattice compounds showing the behavior of a small-gap semiconductor at temperatures below 7 K. We review and discuss the magnetic, transport and specific-heat measurements performed on single crystals of CeNiSn and polycrystals of CeRhSb. Prerequisites for gap formation are deduced from the effects of substitution and application of a magnetic field and pressure on the gapped state.

DOI： 10.1016/0921-4526(94)91868-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BALTZER SCI PUBL BV  

Zero-, longitudinal and transverse muSR measurements are reported on CeNiSn, CePdSn and CePtSn. Below 1 K CeNiSn exhibits strong magnetic correlations, up to possible short range order, but a magnetic phase transition did not occur down to 0.033 K. CePdSn and CePtSn signal their transition into the ordered antiferromagnetic phase by a spontaneous spin precession signal. The second magnetic phase transition in CePtSn reveals itself by the onset of a more complex spin precession pattern. Most unusual is the formation of a paramagnetic state with frozen random spin structure in CePtSn about one Kelvin above T(N).

DOI： 10.1007/BF02069452

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The specific heat C of CeNi1-xPtxSn has been measured at temperatures T between 1.3 and 60 K. With increasing Pt concentration x from 0 to 0.2, the ratio C/T at 1.5K recovers from a reduced value of 0.10J/K2 mol due to the gapping (x = 0) to an enhanced value of 0.34 J/K2 Mol (x = 0.2). This gap suppression is discussed in terms of reduction of the c-f hybridization and destruction of coherence.

DOI： 10.1016/0921-4526(93)90587-V

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Between 1 K and 33 mK CeNiSn behaves as a paramagnet, approaching magnetic order, but no transition is observed. A strong reduction in the moment participating in the magnetic correlations is likely. The La-doped compounds give no magnetic response down to 1.5 K. CePtSn shows unusual spin freezing just above T(N) almost-equal-to 8 K and a sharp transition into a more complex spin order around 5.2 K.

DOI： 10.1016/0921-4526(93)90589-X

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The magnetic. transport and thermal properties are reported on a single crystal of CePtSn which is isostructural with the Kondo semiconductor CeNiSn. The Ce ions in CePtSn are trivalent with 4f states governed by a strong crystal field causing an overall splitting of about 500 K. The Kondo effect is manifest by the double-peak structure of the magnetic part of the resistivity rho(m)(T) possessing maxima at 10 and 140 K. Below the antiferromagnetic transition at 7.5 K, another transition appears in both the specific heat C(T) and rho(m)(T) at 5.0 K. A metamagnetic transition occurs in magnetic fields around 9 and 11 T applied along the a and b axes, respectively. A magnetic phase diagram is presented based on the combined results of the field dependence of C(T) and the temperature dependence of the metamagnetic transition. These results are discussed in connection with the problem of the gap formation in CeNiSn.

DOI： 10.1016/0921-4526(93)90061-A

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：PLENUM PRESS DIV PLENUM PUBLISHING CORP  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：EDITIONS PHYSIQUE  

The formation of magnetic correlations in CeNiSn has been studied by muon spin rotation and relaxation (mu-SR) spectroscopy covering the temperature range from 250 K to 33 mK. Mainly a single crystalline sample was used. At high temperatures (greater-than-or-equal-to 2 K) a behaviour similar to that of a spin fluctuator like UAl2 is observed, meaning that over the whole temperature range the paramagnetic moments fluctuate extremely fast (greater-than-or-equal-to 3 . 10(14) Hz). Below 1 K the material exhibits properties typical for a paramagnet moving towards magnetic order, but no transition into long-range order could be observed down to the lowest measured temperature. The dependences of muon spin relaxation rate and muon spin precession frequency on external field (applied parallel to the a-axis) are unusual and indicate the formation of extended spin correlations up to short-range order.

DOI： 10.1209/0295-5075/19/7/014

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J-GLOBAL

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：English  

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Language：English  

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Language：Japanese   Publisher：京都大学原子炉実験所  

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：京都大学原子炉実験所  

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Language：English   Publisher：Kumamoto University  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan  

CiNii Books

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Language：Japanese  

J-GLOBAL

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：English   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：English  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：English   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：京都大学原子炉実験所  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：English  

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Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：一般社団法人日本物理学会  

CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Event date： 2019.12

Presentation type：Oral presentation (general)  

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Event date： 2019.9

Presentation type：Oral presentation (general)  

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Language：Japanese  

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Language：English  

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Language：Japanese  

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Language：Japanese  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese  

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