High temperature ferromagnetism in (Mn, Li)-codoped ZnO: First-principles study

The magnetic properties of (Mn, Li)-codoped ZnO are investigated based on density functional theory using the Perdew-Burke-Ernzerhof form of generalized gradient approximation. It is found Mn doped ZnO system favors antiferromagnetism (AFM) ordering, while four different geometrical configurations of (Mn, Li)-codoped ZnO prefer stable ferromagnetism (FM) ordering. These results indicate that dopant Li can effectively alter magnetic coupling in ZnMnO system and results in high Curie temperature FM ordering. We propose that dopant Li mediates FM coupling through double exchange interaction and RKKY interaction when Li locates near and far from Mn ions, respectively.