Effect of Nitrogen and Fluorine Co-substitution on the Structure and Magnetic Properties of Cr2 O3.

First-principles density functional calculations were carried out to determine the structure as well as electronic and magnetic properties of N and F co-substituted Cr2 O3 . The formation of strong CrN bonds upon substitution of oxygen with nitrogen leads to large distortions in the local structure and changes in magnetic moments, which are partly compensated by co-substitution with fluorine. The effects of spin-orbit coupling are relatively weak, but its combination with local structural distortions gives rise to canting of spins and an overall magnetic moment in N, F co-substituted Cr2 O3 . Experimentally, we observe spin canting in N, F co-substituted Cr2 O3 with considerable enhancement in the coercive field at low temperatures.