Evidence of a barrier oxidation dependence on the interfacialmagnetism in co/alumina based magnetic tunnel junctions Page: 1 of 13

                                
Evidence of a barrier oxidation dependence on the
interfacial magnetism in Co/alumina based magnetic tunnel
junctions
N.D. Telling', G. van der Laan', S. Ladak2, R.J. Hicken2 and E. Arenholz3
Magnetic Spectroscopy Group, CCLRC Daresbury Laboratory, Warrington WA4
4AD, UK
2University of Exeter, Stocker Road, Exeter EX4 4QL, UK
3Advanced Light Source, Berkeley, CA 94720, USA
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 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.
72.25.Mk, 75.70.Cn, 78.70.Dm

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