Spin motive forces due to magnetic vortices and domain walls

TL;DR

This paper investigates the voltages generated by moving magnetic vortices and domain walls due to time-dependent magnetization, revealing how these voltages depend on material parameters and offering methods to measure key physical constants.

Contribution

It provides detailed calculations of spin motive forces in vortex and domain wall dynamics, highlighting their dependence on the $eta$ parameter and damping, and proposes experimental techniques to measure these parameters.

Findings

Voltage dependence on magnetic field differs between 1D and vortex domain walls.

The voltage-field relationship around Walker breakdown depends on the $eta$ to damping ratio.

Phase difference in vortex disks under AC fields reveals the $eta$ parameter.

Abstract

We study spin motive forces, i.e, spin-dependent forces, and voltages induced by time-dependent magnetization textures, for moving magnetic vortices and domain walls. First, we consider the voltage generated by a one-dimensional field-driven domain wall. Next, we perform detailed calculations on field-driven vortex domain walls. We find that the results for the voltage as a function of magnetic field differ between the one-dimensional and vortex domain wall. For the experimentally relevant case of a vortex domain wall, the dependence of voltage on field around Walker breakdown depends qualitatively on the ratio of the so-called $\beta$-parameter to the Gilbert damping constant, and thus provides a way to determine this ratio experimentally. We also consider vortices on a magnetic disk in the presence of an AC magnetic field. In this case, the phase difference between field and voltage on the edge is determined by the $\beta$ parameter, providing another experimental method to determine this quantity.