Superconductivity at 4.6 K in the Cr-based nitride La₃Cr_10–x N₁₁

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
² School of Physical Sciences, University of Chinese Academy of Sciences - Beijing 100190, China
³ Department of Physics and Beijing Key Laboratory of Opto- electronic Functional Materials and Micro-nano Devices, Renmin University of China - Beijing 100872, China
⁴ School of Physical Science and Technology, ShanghaiTech University - Shanghai 201210, China
⁵ Songshan Lake Materials Laboratory - Dongguan, Guangdong 523808, China
⁶ Kavli Institute for Theoretical Sciences - Beijing 100190, China

^(a) Welyman@iphy.ac.cn (corresponding author)
^(b) jlluo@iphy.ac.cn (corresponding author)

Received: 2 November 2019
Accepted: 7 January 2020

Abstract

A new Cr-based superconductor is discovered in cubic nitride , which is isostructural with . A cubic crystal structure of was determined by single-crystal X-ray diffraction. The superconducting transition temperature T_c from resistivity measurement is 4.6 K, while magnetization and specific heat measurements confirm its bulk property. The upper critical field of H_c2 is about 12.2 T, exceeding the Pauli paramagnetic limit. It is found that the crystallinity and stoichiometry of the samples play important roles in the observation of superconductivity in .