Stacking order-dependent sign-change of microwave phase due to eddy currents in nanometer-scale NiFe/Cu heterostructures
Type
PreprintKAUST Grant Number
Grant No. OSR-2015-CRG4-2626Date
2019-07-18Preprint Posting Date
2019-02-18Online Publication Date
2019-07-18Print Publication Date
2019-07-15Permanent link to this record
http://hdl.handle.net/10754/660852
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Show full item recordAbstract
In the field of spintronics, ferromagnetic/non-magnetic metallic multilayers are core building blocks for emerging technologies. Resonance experiments using stripline transducers are commonly used to characterize and engineer these stacks for applications. Up to now in these experiments, the influence of eddy currents on the excitation of the dynamics of ferromagnetic magnetization below the skin-depth limit was most often neglected. Here, using a coplanar stripline transducer, we experimentally investigated the broadband ferromagnetic resonance response of NiFe/Cu bilayers a few nanometers thick in the sub-skin-depth regime. Asymmetry in the absorption spectrum gradually built up as the excitation frequency and Cu-layer thickness increased. Most significantly, the sign of the asymmetry depended on the stacking order. Experimental data were consistent with a quantitative analysis considering eddy currents generated in the Cu layers and the subsequent phaseshift of the feedback magnetic field generated by the eddy currents. These results extend our understanding of the impact of eddy currents below the microwave magnetic skin-depth and explain the lineshape asymmetry and phase lags reported in stripline experiments.Citation
Appl. Phys. Lett. 115, 032403 (2019)Sponsors
We acknowledge financial support from the French national research agency (ANR) (Grant No. ANR-15-CE24-0015-01) and KAUST (Grant No. OSR-2015-CRG4-2626). We also thank M. Gallagher-Gambarelli for the critical reading of the manuscript.Publisher
arXivarXiv
1902.06501Additional Links
https://arxiv.org/pdf/1902.06501http://arxiv.org/pdf/1902.06501
ae974a485f413a2113503eed53cd6c53
10.1063/1.5093150