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Improved Thermal Stability of Gmr Spin Valve Films

Published online by Cambridge University Press:  15 February 2011

R. D. Mcmichael
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899
W. F. Egelhoff Jr
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899
Minh Ha
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899
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Abstract

In order to improve the thermal stability of magnetic multilayer “spin valve” structures, we have measured the magnetic and magnetoresistive properties of a number of samples with the general structure of NiO/Co/Cu/Co/Cu/Co/NiO as a function of annealing time at 250 °C. The magnetoresistance (MR) of the samples annealed in air decreases proportionally to the square root of the annealing time. For samples annealed in a vacuum, the decrease in magnetoresistance is reduced, but not eliminated. Magnetometry of a vacuum annealed NiO/Co/NiO sample shows a magnetization reduction and a coercivity increase which suggest oxidation of the NiO-biased “outer” Co layers of the spin valve structure. For increasing NiObiased Co layer thickness, we show enhanced thermal stability and even increasing MR with annealing time for samples with the thickest outer Co layers.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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