Increased ferromagnetic resonance linewidth and exchange anisotropy in NiFe/FeMn bilayers

Journal Article · Sun Mar 15 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3086292· OSTI ID:21190093

Shujuan, Yuan; Liming, Yu; Shixun, Cao; Xinluo, Zhao ^[1]; Baojuan, Kang ^[1]

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1. Department of Physics, Shanghai University, Shanghai 200444 (China)

In the past investigations, the exchange-biased bilayers show much larger ferromagnetic resonance (FMR) linewidth than that of single ferromagnetic layer films. However, the mechanism of the large linewidth remains controversial. In this paper, the FMR linewidths of NiFe/FeMn bilayers prepared by dc magnetron sputtering system are systematically studied. Besides the intrinsic damping and magnetic inhomogeneity, the extrinsic relaxation based on two-magnon scattering process should be also considered to explain the strong in-plane angular dependence of the linewidths. The fitting of the out-of-plane angular dependence of the linewidths shows that the intrinsic Gilbert damping effect plays a major role in the increased linewidth in the bilayers. The value of the g factor increases due to the effect of the exchange coupling at the NiFe/FeMn interface, resulting in an enhancement in the Gilbert damping factor G. The fitting results indicate that the line broadening of the exchange-biased films is related to the exchange anisotropy. The effects of FeMn layer thickness, growth sequence of FeMn layer, and temperature on the linewidths further approve this interpretation.

• OSTI ID: 21190093
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 6 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
CRYSTAL GROWTH
DEPOSITION
FERROMAGNETIC MATERIALS
FERROMAGNETIC RESONANCE
INTERFACES
IRON ALLOYS
LANDE FACTOR
LAYERS
LINE BROADENING
LINE WIDTHS
MAGNETISM
MAGNETRONS
MAGNONS
MANGANESE ALLOYS
NICKEL ALLOYS
RELAXATION
SPUTTERING
THIN FILMS