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Ferromagnetic resonance and damping properties of CoFeB thin films as free layers in MgO-based magnetic tunnel junctions

Published

Author(s)

Xiaoyong X. Liu, Wenzhe N. Zhang, Matthew J. Carter, Gang N. Xiao

Abstract

We have investigated the magnetization dynamics of sputtered Co_{40}Fe_{40}B_{20} thin films in a wide range of thickness used as free layers in MgO-based magnetic tunneling junctions, with the technique of broadband ferromagnetic resonance (FMR). We have observed a large interface-induced magnetic perpendicular anisotropy in the thin film limit. Out-of-plane angular dependency FMR measurement revealed the contributions of two different damping mechanisms to the FMR linewidth in thick and thin film limits, based on the analysis using Arias-Mills formula. In thinner films (4 nm). Lastly, we have observed an inverse scaling of Gilbert damping constant with film thickness. We explained this by spin pump effect and an intrinsic damping constant of 0.004 in the FeCoB alloy film is determined.
Citation
Journal of Applied Physics

Keywords

CoFeB, damping, ferromagnetic resonance, magnetic tunnel junctions

Citation

Liu, X. , Zhang, W. , Carter, M. and Xiao, G. (2011), Ferromagnetic resonance and damping properties of CoFeB thin films as free layers in MgO-based magnetic tunnel junctions, Journal of Applied Physics (Accessed May 20, 2024)

Issues

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Created August 18, 2011, Updated February 19, 2017