Exchange Bias Relaxation in CoO-Biased Films

Published

May 1, 2000

Author(s)

Robert McMichael, Chang H. Lee, Mark D. Stiles, F Serpa, P J. Chen, William F. Egelhoff Jr.

Abstract

Because the memory of the bias direction is carried by the antiferromagnetic order in exchange bias films, the stability of the antiferromagnetic order is critical to the existence of the exchange bias field. Ferromagnetic resonance was used to measure the relaxation behavior of polycrystalline CoO films coupled to films of Ni₈₀Fe₂₀, probing the system on the time scale of the experiment, approximately equal to} 10³ s, and the time scale of the magnetic precession, approximately equal to} 10³s, and the time scale of the magnetic precession, approximately equal to10^-10s. Unidirectional anisotropy (exchange biasing) and isotropic resonance field shifts are observed at the lowest temperatures. Above the apparent exchange bias blocking temperature, isotropic resonance field shifts persist. At still higher temperatures, diminishing resonance field shifts are accompanied by peaks in the FMR linewidth. The results highlight the effects of varying relaxation rates in the CoO relative to the two experimental time scales.

Citation

Journal of Applied Physics

Volume

87

Issue

No. 9

Pub Type

Journals

Keywords

anisotropy, antiferromagnetic, exchange bias relaxation, ferromagnetic resonance

Citation

McMichael, R. , Lee, C. , Stiles, M. , Serpa, F. , Chen, P. and Egelhoff Jr., W. (2000), Exchange Bias Relaxation in CoO-Biased Films, Journal of Applied Physics (Accessed December 13, 2024)