Theoretical Study of the Stripline Ferromagnetic Resonance Response of Metallic Ferromagnetic Films Based on an Analytical Model

Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements. We show an experimental study in the well-known Py/Pt system by using a coplanar waveguide (CPW). Results obtained demonstrate that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line. A progressive reduction of this width evidences that SRE contribution to the measured transverse voltage signal becomes negligibly small for sample width below 200 μm. A numerical solution of the Maxwell equations in the CPW-sample setup, by using the Landau-Lifshitz equation with the Gilbert damping term (LLG) as the constitutive equation of the media, and with the proper set of boundary conditions, confirms the obtained experimental results.

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A two dimensional analytical model for the study of ferromagnetic resonance responses of single and multilayer films

Balaji

Kostylev

2017

Journal of Applied Physics

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An advanced analytical formulation to model the response of coplanar and stripline based broadband ferromagnetic resonance (FMR) for single and multilayer ferromagnetic films is presented. Several numerical examples are provided implementing the formulation. The model accounts for exchange interactions as well as exchange boundary conditions at the film surfaces and the film interfaces (in the case of multilayer films). The solutions to the Landau-Lifshitz equation and relevant Maxwell's equations are conducted in Fourier space and are transformed back to real space as required to ensure computational efficiency and to avoid length scale incompatibility due to the experiment geometry. This work presents several numerical examples pertaining to the effect of waveguide geometry and microwave eddy current shielding on the shape of coplanar and stripline FMR responses of single-layer ferromagnetic films. Additionally, the effect of microwave eddy current shielding and distance (dielectric spacer thickness) of the film from the transducer on the stripline FMR responses, dynamic magnetization, magnetic field strength, and precession angle for multilayer film samples is discussed.

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Theoretical Study of the Stripline Ferromagnetic Resonance Response of Metallic Ferromagnetic Films Based on an Analytical Model

Cited by 4 publications

References 26 publications

Excitation and reception of magnetostatic surface spin waves in thin conducting ferromagnetic films by coplanar microwave antennas. Part I: Theory

Excitation and reception of magnetostatic surface spin waves in thin conducting ferromagnetic films by coplanar microwave antennas. Part I: Theory

Suppression of spin rectification effects in spin pumping experiments

A two dimensional analytical model for the study of ferromagnetic resonance responses of single and multilayer films

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