Coherent Microwave Driving of Domain Wall Depinning in a Ferrimagnetic Garnet

TL;DR

This paper demonstrates resonant microwave excitation of a domain wall in a ferrimagnetic garnet, enabling controlled depinning and manipulation of magnetic textures through localized nonlinear dynamics.

Contribution

It introduces a method to coherently control domain wall motion using resonant microwave fields, revealing nonlinear dynamics and depinning mechanisms in ferrimagnetic garnets.

Findings

Identification of a low-frequency mode inside the magnon gap linked to domain wall oscillations.

Microwave-driven nonlinear regime facilitates domain wall depinning at lower magnetic fields.

Micromagnetic simulations show progression from localized oscillations to complete depinning.

Abstract

Coherent control of domain wall dynamics offers a route to fast manipulation of magnetic textures beyond thermally activated motion. We demonstrate resonant excitation of linear and nonlinear dynamics of a pinned domain wall in a ferrimagnetic garnet thin film driven by a microwave field. Using scanning nitrogen-vacancy magnetometry and nonlocal spin-pumping measurements, we identify a low-frequency mode inside the magnon gap, originating from the localized oscillatory motion of a domain wall across a pinning line defined by a Pt stripline. Upon increasing the microwave drive into the nonlinear regime, this mode enables domain wall depinning at reduced external magnetic fields. Micromagnetic simulations reveal a progression from localized oscillations to partial relocation between pinning sites and, ultimately, complete escape from the pinning region with increasing driving power. These results establish resonant excitation of domain walls at engineered pinning sites as a mechanism for manipulating magnetic textures via localized nonlinear dynamics.