A rigorous two-dimensional model for the stripline ferromagnetic resonance response of metallic ferromagnetic films

TL;DR

This paper develops a detailed two-dimensional numerical model to analyze the stripline ferromagnetic resonance response of metallic ferromagnetic films, highlighting the effects of eddy currents and stripline width on FMR signals.

Contribution

The paper introduces a new 2D numerical model for FMR response in metallic ferromagnetic films, emphasizing the impact of eddy currents and stripline dimensions.

Findings

Eddy current effects decrease with narrower striplines.

Higher-order standing spin waves are excited due to conductivity effects.

Eddy currents are significant in wide striplines but negligible in narrow ones.

Abstract

In this work we constructed a two-dimensional numerical model for calculation of the stripline ferromagnetic resonance (FMR) response of metallic ferromagnetic films. We also conducted numerical calculations by using this software. The calculations demonstrated that the eddy current contribution to the FMR response decreases with a decrease in the stripline width. The most important manifestations of the conductivity (eddy current) effect are excitation of the higher-order standing spin waves across the film thickness in the materials for which the standing spin wave peaks would be absent in cavity FMR measurements and strong dependence of the off-resonance series conductance of the stripline on the stripline width. Whereas the contribution of the eddy currents to the stripline FMR response can be very significant, because wide striplines (100nm+) are conventionally used for the FMR measurements, it is negligible in the case of excitation of spin waves, just because very narrow stripline transducers (0.5-5micron wide) are required in order to excite spin waves in metallic ferromagnetic films in a noticeable frequency/applied field range.