Ferromagnetism in ZnO co-doped with Mn and N studied by soft x-ray magnetic circular dichroism

We have investigated the electronic structure of ZnO:Mn and ZnO:Mn,N thin films using x-ray magnetic circular dichroism (XMCD) and resonance-photoemission spectroscopy. From the Mn 2p -> 3d XMCD results, it is shown that, while XMCD signals only due to paramagnetic Mn(2+) ions were observed in ZnO:Mn, nonmagnetic, paramagnetic, and ferromagnetic Mn(2+) ions coexist in ZnO:Mn,N. XMCD signals of ZnO:Mn,N revealed that the localized Mn(2+) ground state and Mn(2+) state hybridized with ligand hole coexisted, implying p-d exchange coupling. In the valence-band spectra, spectral weight near the Fermi level was suppressed, suggesting that interaction between magnetic moments in ZnO:Mn,N has localized nature. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3643044]