Nickel-based phosphide superconductor with infinite-layer structure, BaNi2P2

TL;DR

This paper reports the discovery of BaNi2P2, a nickel-based superconductor with an infinite-layer structure that exhibits superconductivity at around 3 K and shows metallic and paramagnetic properties.

Contribution

It introduces BaNi2P2 as a new bulk superconductor with an infinite-layer structure, expanding the family of nickel-based superconductors.

Findings

BaNi2P2 has an infinite-layer structure.

Superconducting transition at ~3 K.

Exhibits metallic conduction and Pauli paramagnetism.

Abstract

Analogous to cuprate high-Tc superconductors, a NiP-based compound system has several crystals in which the Ni-P layers have different stacking structures. Herein, the properties of BaNi2P2 are reported. BaNi2P2 has an infinite-layer structure, and shows a superconducting transition at ~3 K. Moreover, it exhibits metallic conduction and Pauli paramagnetism in the temperature range of 4-300 K. Below 3 K, the resistivity sharply drops to zero, and the magnetic susceptibility becomes negative, while the volume fraction of the superconducting phase estimated from the diamagnetic susceptibility reaches ~100 vol.% at 1.9 K. These observations substantiate that BaNi2P2 is a bulk superconductor.