Soft-x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO

The electronic properties of cobalt-doped ZnO grown by pulsed laser deposition, were examined through element specific soft-x-ray-absorption techniques in the vicinity of the Co [L.sub.2.3 edge, the oxygen K edge, and at the Zn [L.sub.3] edge. The findings are consistent with a polaron percolation model in which the ferromagnetic coupling is mediated by shallow donor electrons trapped in oxygen vacancies and couples the Co atoms substituted on Zn sites in the hexagonal wurtzite ZnO structure.