The role of unintentional hydrogen on magnetic properties of Co doped ZnO

Abstract

The correlation between the positioning of hydrogen and magnetic properties of Co doped ZnO are investigated using ab initio methodology. It is found that hydrogen can both sit in interstitial Zn-O mid bonds and substitute oxygen forming multicentre bonds with zinc. However the substitutional hydrogen is slightly more stable by 0.37 eV than the interstitial hydrogen. It is also found that mobile hydrogen ions in ZnO are trapped by Co ions or Co complexes to form variety of highly stable Co-H complexes in ZnO host lattice. Charge transfer from hydrogen to neighboring Co's 3d orbitals leads to both the stabilization of ferromagnetic ordering among Co ions and the reduction of Co ion magnetic moment. © 2011 American Institute of Physics.