First-principles density-functional theory calculations were used to study the

magnetic properties of ZnO:Cr; with and without vacancies. The results indicated

that the doping of Cr into ZnO introduced obvious spin polarization around the

Fermi level and a total magnetic moment of 3.77μB. The ferromagnetism exchange

interaction between Cr atoms was short-ranged and decreased with increasing Cr

separation distance. It was suggested that the ferromagnetic state was not stable at

low concentrations of Cr. The presence of O vacancies could make the halfmetallic

ferromagnetic state of the system more stable, so that higher Curie

temperature ferromagnetism could be expected. Nevertheless, Zn vacancies could

result in the ferromagnetism stability decreasing slightly. The calculated formation

energy showed that a VZn+CrZn complex formed spontaneously under O-rich

conditions. However, under Zn-rich conditions, a complex of VO+CrZn formed

more easily. Thus, ZnO doped with Cr could exhibit a concentration of vacancies

that influenced the magnetic properties.

Theoretical Study of the Magnetic Interaction of Cr-Doped ZnO with and Without

Vacancies. F.Wang, Z.Pang, L.Lin, S.Fang, Y.Dai, S.Han: Journal of Magnetism

and Magnetic Materials, 2009, 321[19], 3067-70