Nickel-based layered superconductor, LaNiOAs

Rietveld analysis of the powder X-ray diffraction of a new layered oxyarsenide, LaNiOAs, which was synthesized by solid-state reactions, revealed that LaNiOAs belongs to the tetragonal ZrCuSiAs-type structure (P4/nmm) and is composed of alternating stacks of La-O and Ni-As layers. The electrical and magnetic measurements demonstrated that LaNiOAs exhibits a superconducting transition at 2.4 K, and above this, LaNiOAs shows metallic conduction and Pauli paramagnetism. The diamagnetic susceptibility measured at 1.8 K corresponded to ∼20% of perfect diamagnetic susceptibility, substantiating that LaNiOAs is a bulk superconductor. - Graphical abstract: A new layered oxyarsenide, LaNiOAs, which exhibits a superconducting transition at 2.4 K, was synthesized by solid-state reactions. This compound had a tetragonal ZrCuSiAs-type structure similar to recently discovered superconductors, LaFeOP, LaFeOAs, and LaNiOP. Superconductivity was observed for undoped LaNiOAs, which differs from the case of LaFeOAs. Display Omitted