High temperature ferromagnetism in Fe-Doped ZnO: a density functional investigation

The electronic structure and related magnetic properties of Fe-doped ZnO system is analyzed in presence of both O- and Zn-vacancy ill the framework of TB-LMTO-ASA method within LSDA. Although for the Fe-doped ZnO system, the ground state is antiferromagnetic, in presence of O-and Zn-vacancy the magnetic mechanism is drastically altered. Utilizing the two-centered tight binding model of Anderson and Hasegawa, we have investigated the nature of the two competing interactions : antiferromagnetic super-exchange versus ferromagnetic double-exchange interactions, as a function of the Fe-Fe separation by supercell calculations. The results reveal that for obtaining long-range half-metallic ferromagnetism, Zn-vacancy is more crucial than O-vacancy.