Pinned orbital moments in uncompensated antiferromagnetic Co doped ZnO
Sprache des Titels:
Low temperature Co K-edge x-ray magnetic circular dichroism spectra at different field cooling conditions were recorded to study the imprinted magnetization in antiferromagnetic (AFM) Co doped ZnO (Co:ZnO) films which manifests itself in a vertical exchange bias effect. Co:ZnO films with 50% and 60% doping concentrations were investigated to provide a high degree of pinned magnetic moments. The measurements reveal a change at the main absorption energy of the spectra, while the signal obtained at the preedge stays unaffected by the cooling conditions. Therefore,the pinned uncompensated AFM moments, resulting in an imprinted magnetization, are predominantly of orbital character and are independent of ferromagnetic layers.