In silico CrNF, a half-metallic ferromagnetic nitride–fluoride mimicking CrO2

Abstract

Isoelectronic with CrO2, CrNF is proposed in silico based on rutile derived structures with DFT computations. The ground state structure defined from cohesive energies is of MgUO4-type, characterized by short covalent Cr–N and long ionic Cr–F distances. Like CrO2 it is a half-metallic ferromagnet with M=2μB/FU integer magnetization with reduced band gap at minority spins. Major difference of magnetic response to pressure characterizes CrNF as a soft ferromagnet versus hard magnetic CrO2. The chemical bonding properties point to prevailing covalent Cr–N versus ionic Cr–F bonding. Different synthesis routes are examined.