Stacking order-dependent sign-change of microwave phase due to eddy currents in nanometer-scale NiFe/Cu heterostructures
arXiv:1902.06501 · doi:10.1063/1.5093150
Abstract
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.
References in corpus (13)
- Nonlocal magnetization dynamics in ferromagnetic heterostructures
- Quantifying spin Hall angles from spin pumping: Experiments and Theory
- Ultra-low magnetic damping of a metallic ferromagnet
- The 2014 Magnetism Roadmap
- Spin precession and inverted Hanle effect in a semiconductor near a finite-roughness ferromagnetic interface
- Radiative damping in wave guide based FMR measured via analysis of perpendicular standing spin waves in sputtered Permalloy films
- Dependence of spin pumping spin Hall effect measurements on layer thicknesses and stacking order
- Direct evidence for minority spin gap in the Co2MnSi Heusler alloy
- Inductive detection of field-like and damping-like AC inverse spin-orbit torques in ferromagnet/normal metal bilayers
- Dependence of nonlocal Gilbert damping on the ferromagnetic layer type in FM/Cu/Pt heterostructures
- Dynamic pinning at a Py/Co interface measured using inductive magnetometry
- Eddy current interactions in a Ferromagnet-Normal metal bilayer structure, and its impact on ferromagnetic resonance lineshapes
- Eddy-current effects on ferromagnetic resonance: Spin wave excitations and microwave screening effects