X-ray absorption and magnetic circular dichroism studies of annealed magnetic tunnel junctions
- Department of Physics, University of Bielefeld, Nano Device Group, P.O. Box 100131, 33501 Bielefeld (Germany)
The magnetic and chemical interface properties of Mn-Ir/Co-Fe/Al+oxidation/Ni-Fe magnetic tunnel junctions are investigated for different barrier thickness, oxidation times, and annealing conditions by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. For underoxidized samples the formation of Co-Fe-Al alloy at the lower barrier interface during optimal annealing is observed. For optimally oxidized and overoxidized samples FeO{sub x} is formed during oxidation, which is reduced by Mn diffusing to the barrier during annealing. The reduction of FeO{sub x} is accompanied by an increase of the interfacial magnetic Fe moment, whereas the Co moments hardly change with the postannealing. Comparison of these results with transport properties of the junctions shows that their polycrystalline structure has to be taken into account to understand the annealing temperature and oxidation state dependence of the tunneling magnetoresistance effect.
- OSTI ID:
- 20711761
- Journal Information:
- Journal of Applied Physics, Vol. 97, Issue 12; Other Information: DOI: 10.1063/1.1939086; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION SPECTROSCOPY
ALUMINIUM ALLOYS
ANNEALING
COBALT ALLOYS
CRYSTAL STRUCTURE
DIFFUSION
IRIDIUM ALLOYS
IRON ALLOYS
MAGNETIC CIRCULAR DICHROISM
MAGNETIC MOMENTS
MAGNETISM
MAGNETORESISTANCE
MANGANESE ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
OXIDATION
POLYCRYSTALS
SUPERCONDUCTING JUNCTIONS
TUNNEL EFFECT
X-RAY SPECTROSCOPY