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Giant Magnetoresistance in Sputter-Deposited Granular Ag-Co Thin Films

Published online by Cambridge University Press:  03 September 2012

W. Y. Lee
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
V. R. Deline
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
G. Gorman
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
A. Kellock
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
D. Miller
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
D. Neiman
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
R. Savoy
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
J. Vazquez
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
R. Beyers
Affiliation:
IBM Almadén Research Center, San Jose, CA 95120
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Abstract

Giant Magnetoresistance (GMR) is reported in as-deposited Ag1−xCox (x = 0.26–0.53) films co-sputtered on Si from separate Ag and Co targets. GMR ratios (10 K Oe Maximum field) exceeding 0.50 and 0.19 at 5 and 295 K, respectively, are observed for the Ag067Co033 films deposited at ≃28 to 175 °C. The Maximum ratios of 0.55 and 0.24 occur at a substrate temperature of ≃125 °C for these films. The ratios decrease rapidly for the films deposited at temperatures > 175 °C and reduce to ≃0.15 and 0.04 at deposition temperatures >300 °C. This deposition temperature dependence of GMR ratios is interpreted in terms of the change in the spin-dependent interfacial electron scatterings due to the change in the size and number of ferromagnetic Co particles within the electron mean free path. The initial increase and the subsequent decrease in GMR ratios with increasing deposition temperature are attributed to the increase in the mean free path, and the Co and Ag particle size, respectively. Changes in mean free path are obtained from the resistivities of these films while changes in Ag and Co particles are deduced mainly from the X-ray diffraction patterns, transmission electron Micrographs, and the coercivities of these films.

Type
Research Article
Copyright
Copyright © Materials Research Society 1993

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References

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