On field-driven domain wall motion in compensated ferrimagnetic nanowires

TL;DR

This paper develops a theoretical model for high-speed domain wall motion in ferrimagnetic nanowires near the angular momentum compensation point, explaining experimental observations and guiding future domain wall control.

Contribution

It introduces a nearly exact velocity formula for domain walls in ferrimagnets, valid beyond the Walker breakdown, and explains the absence of precessional torque at the AMCP.

Findings

High domain wall velocities near the AMCP

Absence of precessional torque at the AMCP

Agreement with existing experiments and simulations

Abstract

The fascinating high-speed field-driven domain wall (DW) motion along ferrimagnetic nanowires near the angular momentum compensation point (AMCP) is solved based on the generic ferrimagnetic dynamics. The physics of the absences of precessional torque and infinite high Walker breakdown field at the AMCP is proved under general conditions. Based on the energy conservation principle, an almost exact DW velocity formula, valid beyond the Walker breakdown field, is obtained. Our results agree with all existing experiments and simulations. This theory provides useful guidances to DW manipulation.