Novel interpretation of recent experiments on the dynamics of domain walls along ferrimagnetic strips

TL;DR

This paper presents a comprehensive analysis of domain wall dynamics in ferrimagnetic strips using micromagnetic simulations and models, revealing temperature-dependent behaviors and providing new insights into recent experimental observations.

Contribution

It introduces a combined micromagnetic and collective-coordinates model considering two sublattices, offering new interpretations of domain wall motion and non-adiabatic parameters in ferrimagnets.

Findings

Precessional dynamics become rigid at the angular momentum compensation temperature.

Current-driven domain wall motion can occur along or against the current depending on temperature.

The approach explains large non-adiabatic effective parameters in ferrimagnetic systems.

Abstract

Domain wall motion along ferrimagnets is evaluated using micromagnetic simulations and a collective-coordinates model, both considering two sublattices with independent parameters. Analytical expressions are derived for strips on top of either a heavy metal or a substrate with negligible interfacial Dzyaloshinskii-Moriya Interaction. The work focuses its findings in this latter case, with a field-driven domain wall motion depicting precessional dynamics which become rigid at the angular momentum compensation temperature, and a current-driven dynamics presenting more complex behavior, depending on the polarization factors for each sublattice. Importantly, our analyses provide also novel interpretation of recent evidence on current-driven domain wall motion, where walls move either along or against the current depending on temperature. Besides, our approach is able to substantiate the large non-adiabatic effective parameters found for these systems.