STM Studies of GMR Spin Valves

Published

January 1, 1995

Author(s)

R Misra, T Ha, Y Kadmon, Cedric J. Powell, Mark D. Stiles, Robert McMichael

Abstract

We have investigated the surface roughness and the grain size in giant magnetoresistance (GMR) spin valve multilayers of the general type: FeMn/Ni₈₀Fe₂₀/Co/Cu/Co/Ni₈₀ Fe₂₀ on glass and aluminum oxide substrates by scannin tunneling microscopy (STM). The two substrates give very similar results. These polycrystalline GMR multilayers have a tendency to exhibit larger grain size and increased roughness with increasing thickness of the metal layers. Samples deposited at a low substrate temperature (150K) exhibit smaller grains and less roughness. Valleys between the dome-shaped individual grainsare the dominant form of roughness. This roughness contributes to the ferromagnetic, magnetostatic coupling in these films, an effect termed " orange peel" coupling by Neacute}el. We have calculated the strength of this coupling, based on our STM images, and obtain values generally within about 20% of the experimental values. It appears likely that the ferromagnetic coupling generally attributed to so-called "pinholes" in the Cu when the Cu film thickness is too small is actually "orange peel" coupling caused by these valleys.

Proceedings Title

Materials Research Society Symposium Proceeding

Volume

384

Conference Dates

April 17-21, 1995

Conference Location

San Francisco, CA, US

Conference Title

Materials Research Society Symposium

Pub Type

Conferences

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Citation

Misra, R. , Ha, T. , Kadmon, Y. , Powell, C. , Stiles, M. and McMichael, R. (1995), STM Studies of GMR Spin Valves, Materials Research Society Symposium Proceeding, San Francisco, CA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=620459 (Accessed October 2, 2025)