Superconductivity at 4.6 K in the Cr-based nitride La3Cr10-xN11

A new Cr-based superconductor is discovered in cubic nitride La3Cr10-xN11, which is isostructural with Pr3Cr10-xN11. A cubic crystal structure of La3Cr10-xN11 was determined by single-crystal X-ray diffraction. The superconducting transition temperature T-c from resistivity measurement is 4.6K, while magnetization and specific heat measurements confirm its bulk property. The upper critical field of H-c2 is about 12.2T, 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 La3Cr10-xN11. Copyright (C) EPLA, 2020