Thermal conductivity (κ) of two series of hightemperature superconductors with general formula Sm 1+x Ba 2−x Cu 3 O y have been measured. Both series begin with the same sample of T c = 90.4 K and extend to nonsuperconducting phases. The first series is of 123 cation stoichiometry and variable oxygen content y, the second is a series of solid solutions with variable x. The temperature dependences of κ are very similar for superconducting partner samples from both series (i.e. with the same T c ), whereas the nonsuperconducting samples reveal dramatic differences. We propose to attribute the huge increase of κ and the change of its temperature characteristics of insulating oxygen deficient sample to some additional heat carriers, supposedly of magnetic origin. Absence of this additional heat transport mechanism for insulating solid solution allows to treat it as a proper reference for estimation of phonon contribution in the superconducting 123 compounds.
A hydride sample with nominal composition H 0.7 YBa 2 Cu 3 O 6.1 was synthesized. An X-ray diffraction study showed a phase transition from the tetragonal to orthorhombic cell. It is the first example of such transition among Y–Ba–Cu–O ceramics induced by non-oxygen atoms.
ChemInform Abstract Two structural changes due to oxygen deficiency or temp.-induced oxygen atom disordering are observed and used to explain the extraordinary behavior of Tc in the oxygen deficient region. First, oxygen disordering in the b-axis Cu-O chains results in a set of mutually perpendicular and inequivalently occupied Cu-O chains which is possibly more favorable for superconductivity. A second effect, which may become dominating at lower oxygen concentrations, is observed for the Cu-O planes existing between the yttrium and barium ion layers.
In 14 . -Single crystals of the new title compound are synthesized from the elements in a Pb flux (1150°C, 2 h). As revealed by single crystal XRD, Ce6Pt11In14 crystallizes in the monoclinic space group C2/m with Z = 2. It represents a new type of crystal structure of intermetallic compounds in which one of the Pt atoms is coordinated by eight neighbors only, forming a distorted cube. All the other Pt atoms have a trigonal prismatic coordination with either three or four additional atoms. -(STEPIEN-DAMM, J.; BUKOWSKI, Z.; ZAREMBA, V. I.; PIKUL, A. P.; KACZOROWSKI*, D.; J.
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