Evidence of a barrier oxidation dependence on the interfacial magnetism in Co/alumina based magnetic tunnel junctions

Abstract

Soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co L2,3 edge have been applied to explore the near-interfacial magnetism of Co electrodes in Co/alumina based magnetic tunnel junctions. By taking into account the formation of CoO at the ferromagnetic (FM)/barrier interface, the change in the total magnetic moment on metallic Co atoms as a function of barrier oxidation has been determined. The results demonstrate a strong correlation between the Co moments and measured TMR values, and an enhancement in the Co moments for moderate oxidation times. © 2006 American Institute of Physics.