Effect of nonadiabatic spin transfer torque on domain wall resonance frequency and mass

TL;DR

This paper investigates how nonadiabatic spin transfer torque influences the resonance frequency and effective mass of magnetic domain walls, revealing a red shift in frequency and increased mass with higher nonadiabatic contributions.

Contribution

It provides an analytical and simulation-based analysis of the impact of nonadiabatic spin transfer torque on domain wall resonance properties, highlighting new effects not previously characterized.

Findings

Resonance frequency exhibits a red shift due to nonadiabatic torque.

Domain wall mass increases with higher nonadiabatic to adiabatic torque ratio.

Damped sinusoidal oscillations occur around equilibrium in the absence of currents.

Abstract

The dynamics of a magnetic domain wall in a semi circular nanowire loop is studied by an analytical model and micromagnetic simulations. We find a damped sinusoidal oscillation of the domain wall for small displacement angles around its equilibrium position under an external magnetic field in the absence of currents. By studying the effect of current induced nonadiabatic spin transfer torque on the magnetic domain wall resonance frequency and mass, a red shift is found in the resonance frequency and domain wall mass increases by increasing the ratio of nonadiabatic spin torque to adiabatic contribution above 1.