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Large Anisotropy Via Oblique Sputtering of Ta Underlayers

Published online by Cambridge University Press:  14 March 2011

J.E. Bonevich ,
R.D. McMichael ,
C.G. Lee ,
P.J. Chen ,
W. Miller  and
W.F. Egelhoff
J.E. Bonevich
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
R.D. McMichael
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
C.G. Lee
Affiliation:
Changwon National University, Changwon, Kyungnam 641-773, KOREA
P.J. Chen
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
W. Miller
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
W.F. Egelhoff
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Abstract

Anisotropy fields in excesss of 120kA/m(1500Oe)have been produced in 3 nm to 5 nm thick polycrystalline films of Co with Ta underlayers. The unusualy high anisotropy is magnetostatic in origin, and is induced by corrugations on the surface of an obliquely sputtered Ta underlayer. Cross-sectional TEM reveas 8 nm columnar grains of Ta tilted toward the Ta source and elongated perpendicuar to the Ta flux in the film plane. The anisotropy field of the Co film increases with both the underlayer thickness and the angle between theTa source and the film normal. In spin valve samples, the anisotropy is attenuated by more than an order of magnitude across a 4nm thick Cu spacer. Magnetoresistance measurements on a spin valve indicate less than 2° dispersion in hard axis directions, and despite the nanometer-scale roughness of the underlayer, there is weak broadening of the ferromagnetic resonance line.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 614: Symposium F – Magnetic Materials, Structures & Processing for Information… , 2000 , F7.7.1
Copyright
Copyright © Materials Research Society 2000

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References

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