Correlated substitution in paramagnetic Mn2+-doped ZnO epitaxial films

Epitaxial films of Mn2+-doped ZnO were deposited by pulsed laser deposition on alpha-Al2O3(0001) using targets created from Mn2+-doped ZnO nanoparticles. Using x-ray absorption spectroscopy and x-ray magnetic circular dichroism, Mn(II) was found to substitute for Zn(II) in the wurtzite ZnO lattice with only a paramagnetic dichroic component from the Mn and no magnetic component from either the O or Zn. The dichroism reveals that, while substitutional, the Mn2+ distribution in the ZnO lattice is not stochastic. Rather, Mn2+ has a tendency to substitute with higher effective local concentrations than anticipated from a stochastic doping model.