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Abstract: Single phase of CeCuS2 has been prepared by the mixture of CeO2 and Cu2S at 1000  C in CS2/Ar atmosphere. All X-ray diffraction peaks of CeCuS2 are indexed on the basis of the monoclinic system (space group: ) the same as LaCuS2 and NdCuS2. The lattice parameters obtained by Rietveld analysis are nm, nm, nm, and . [Copyright &y& Elsevier]

Abstract: A single phase of (LaO)CuTe has been synthesized by the solid-state reaction. The lattice constants, a and c, refined by Rietveld analysis are 0.41815 and 0.93417 nm, respectively. The temperature dependence of the electrical resistivity shows a metallic behavior above 150 K and changes to a semiconductive behavior below that temperature. The value of the electronic specific heat coefficient estimated from the dependence of the C /T was almost zero. The magnetic susceptibility shows diamagnetism which is attributed to the core diamagnetism. [Copyright &y& Elsevier]

Abstract: We have precisely investigated the crystal structure of various doped samples of (La1−x Ca x O)Cu1−x M x S (, Co, Ni, Zn) in order to understand changes of the electrical properties from a view point of the crystal structure. The distance between LaO and CuS layers along c-axis, increases with increasing electrical resistivity of (La1−x Ca x O)Cu1−x Ni x S and it approaches a value of insulating samples, (La1−x Ca x O)Cu1−x M x S (, Co, Zn). The changes of the electrical properties is considered to be due to the charge transfer between LaO and CuS layer which is caused by the change of . [Copyright &y& Elsevier]

Abstract: We have prepared rare earth oxysulfides (PrO)CuS and (NdO)CuS in order to introduce magnetic moments into the non-magnetic p-type semiconductor (LaO)CuS. Both compounds are semiconductors with high electrical resistivity, and show the paramagnetic behavior. The temperature dependence of the magnetic susceptibility is well explained by the trivalent rare earth ion. However, it deviates from simple Curie Wiess law below 100K due to the crystal field effect on rare earth ions. We have succeeded to reproduce their magnetic properties by the calculation taking the crystal field effect into account using the operator equivalent method. [Copyright &y& Elsevier]

Abstract: Ln 4f partial densities of states (DOSs) in layered oxysulfide semiconductors (LnO)CuS (Ln=Ce, Pr, Nd) have been deduced by means of the Ln 4d–4f resonant photoemission spectroscopy. The Ce 4f DOS contributes just below the valence-band maximum (VBM) of (CeO)CuS, and on going from Ln=Ce to Pr, and to Nd, the 4f DOS shifts toward the deeper binding-energy side, leading no 4f contribution near VBM for Ln=Pr and Nd. The O 2p partial DOSs derived from O Kα emission spectra are almost unchanged with the Ln elements. [Copyright &y& Elsevier]

Abstract: From the radial distribution analysis of X-ray diffraction, the nearest neighbor La–Cl distance and coordination number of Cl around La in molten LaCl3 were estimated to be about 0.28nm and nearly equal to 6, respectively. On the other hand, according to the XAFS measurements, the coordination number of Cl around La was evaluated at about 7. As a result, the local structure of molten LaCl3 was thought to be described as an octahedral-like coordination scheme where La was surrounded by about six or seven Cl''s. This finding led to the formation of octahedral complex ion, LaCl6 3−, which was in agreement with results of Raman spectroscopy by other authors. The La–La distance was evaluated at about 0.5nm from the position of a weak and broad second peak in the correlation function g(r), suggesting that a distorted corner-sharing connection of two octahedral complex species was predominant in the melt. [Copyright &y& Elsevier]

Abstract: The effects of Sr substitution for Ba on the crystal structure, oxygen content and physical properties of polycrystalline samples of R(Ba1−x Sr x )2Cu3O y (R, Pr) have been investigated. The samples were prepared by sintering at a high temperature under reducing atmosphere, followed by annealing under O2 flow. The structure parameters were refined by the Rietveld analysis of X-ray powder diffraction data. The occupation factors of each site were analyzed under the assumption that a part of Sr ions occupies the R site and pushes the same amount of R ions into the Ba site. For the R, the ratio of Sr on the Nd sites increases with x, from 0 for to 0.11 for . The orthorhombicity decreases continuously with x. On the other hand, for R, the site exchange between Sr and Pr does not occur. The orthorhombicity keeps a high value until and drastically becomes zero at . The electrical resistivity and the Néel temperature increases with x until , and then decreases. These results show that the high decrease rate of in Nd(Ba1−x Sr x )2Cu3O y is attributed to the occupation of Ba sites by Nd and the non-superconductivity of PrBa2Cu3O y is not due to the occupation of Ba site by Pr. It is also suggested that the hybridization of Pr 4f and O 2p orbitals which prevents the replacement of Pr by Sr increases with x until and then abruptly turns to decrease. [Copyright &y& Elsevier]

Abstract: X-ray absorption fine structure (XAFS) measurements on rare-earth-alkali metal fluoride systems (0.2 LnF3–0.8 MF: Ln=La, Ce, Nd, Sm; M=Li, Na, K) have been carried out at 300 and 1173K. The local structures around rare-earth-ions in both the solid and liquid phases were evaluated by the curve-fitting analysis, involving anharmonic oscillation effects at the higher temperature. This study revealed that the nearest-neighbour Ln3+–F− distance and the corresponding coordination number of F− around Ln3+ in the molten state mainly depend on the lanthanide species rather than the size of the alkali metal ion. [Copyright &y& Elsevier]

Abstract: We have succeeded to obtain an almost single phase of layered oxysulfide CeOCuS and found a heavy fermion like behavior in this compound. It crystallizes in tetragonal LaOAgS-type structure and the lattice parameters a and c are 0.3923 and 0.8333 nm, respectively. They are smaller than those expected for trivalent Ce ion. This suggests that Ce ions exist in a mixed valence state. The temperature dependence of the specific heat, C shows an upturn below about 7 K. It is expressed by the following relation, . The value of is about 324 mJ/mol K2, which is comparable with that of conventional heavy fermion compounds. The temperature dependence of the electrical resistivity is metallic and obeys the following relation, , below 100 K. The temperature dependence of the magnetic susceptibility is expressed by the sum of Pauli paramagnetic and Curie Weiss terms. The Pauli paramagnetic term has a large value, which corresponds to about 10% that estimated from . The effective magnetic moment , , is smaller than the free ion value of trivalent Ce and indicates about 64% of Ce ions is trivalent. [Copyright &y& Elsevier]