Local structure and magnetism of Co3+ in wurtzite Co:ZnO

Abstract

The structural and magnetic properties of 30% and 50% Co-doped ZnO have been investigated in order to determine the influence of the presence of Co3+ as a potential p-type dopant. For 30% doping, Co3+ could be stabilized in the wurtzite lattice of ZnO without phase separation by providing high oxygen partial pressures during growth. At 50% Co concentration, the crystal lattice destabilizes. X-ray absorption spectroscopy and simulations are used to substantiate the valence and local structure of Co3+. Integral and element selective magnetometry reveals uncompensated antiferromagnetism of the Co atoms irrespective of being present as Co2+ or Co3+.