Superconductivity at 2.2 K in the layered oxypnictide La3Ni 4P4O2

We report the observation of superconductivity in La3Ni 4P4O2 at 2.2 K. The layer stacking in this compound results in an asymmetric distribution of charge reservoir layers around the Ni2P2 planes. The estimated Wilson ratio, R Wâ??5, indicates the presence of strongly enhanced normal-state susceptibility, but many of the basic superconducting characteristics are conventional. The estimated electronic contribution to the specific heat, γâ??6.2 mJ mol-Ni-1 K-2, is about 2/3 of that found in layered nickel borocarbide superconductors. © 2009 The American Physical Society

Crystal Growth of CsCl-type Yb0.24Sn0.76Ru

The Yb-Ru-Sn ternary system was investigated and a new material, Yb0.24Sn0.76Ru, with a simple cubic crystal structure, was discovered. Yb0.24Sn0.76Ru has a smaller lattice parameter a = 3.217(4) Å, than its isostructural YbRu analogue (a = 3.360 Å). Both x-ray diffraction and electron microscopy techniques were used to refine the crystal structure of Yb0.24Sn0.76Ru. It was found that a new compound forms in the CsCl structure, with Ru on the 1a site and a (Yb, Sn) mixture on site 1b. The xrd Rietveld analysis provides the occupation of Yb equal to 0.24, in agreement with the single crystal nano-electron diffraction refinement, which gives the occupation 0.21.JRC.E.6-Actinides researc

Layered nickel based superconductors

We review the properties of Ni-based superconductors which contain Ni{sub 2}X{sub 2} (X=As, P, Bi, Si, Ge, B) planes, a common structural element to the recently discovered FeAs superconductors. We also compare the properties ofthe Ni-and Fe-based systems from a perspective ofelectronic structure as well as structure-property relations