Bulk sensitive x-ray absorption and magnetic circular dichroism investigation of Mn- and Co-doped ZnO thin films

Bulk sensitive L2,3 x-ray magnetic circular dichroism spectra were measured in transmission on Mnand Co-doped ZnO thin films grown by pulsed laser deposition on soft x-ray transparent silicon nitride membranes. The absorption spectra line shapes support that Mn and Co divalent ions substitute Zn ions ruling out the hint of cluster formation. The lack of dichroic signal at the Mn and Co-edges in such bulk sensitive measurements indicates that the ferromagnetism witnessed by vibrating sample magnetometry measurements could arise from delocalized magnetic moments, due to itinerant electrons associated with defects.