Nickel-based Oxyphosphide Superconductor With a Layered Crystal Structure, LaNiOP

Inorg Chem. 2007 Sep 17;46(19):7719-21. doi: 10.1021/ic701200e. Epub 2007 Aug 17.

Abstract

A layered oxyphosphide, LaNiOP, was synthesized by solid-state reactions. This crystal was confirmed to have a layered structure composed of an alternating stack of (La(3+)O(2-))(+) and (Ni(2+)P(3-))(-). We found that the resulting LaNiOP shows a superconducting transition at approximately 3 K. This material exhibited metallic conduction and Pauli paramagnetism in the temperature range of 4-300 K. The resistivity sharply dropped to zero and the magnetic susceptibility became negative at <4 K, indicating that a superconducting transition occurs. The volume fraction of the superconducting phase estimated from the diamagnetic susceptibility reached approximately 40 vol % at 1.8 K, substantiating that LaNiOP is a bulk superconductor.