Fast domain wall propagation in uniaxial nanowires with transverse fields

TL;DR

This paper demonstrates that applying a transverse magnetic field to uniaxial nanowires significantly enhances domain wall propagation speed, surpassing fully anisotropic wires below a critical field, with detailed analytic and numerical analysis.

Contribution

It introduces a novel understanding of how transverse fields can dramatically increase domain wall velocity in uniaxial nanowires, supported by analytic and numerical methods.

Findings

Transverse fields can reverse slow domain wall motion in uniaxial wires.

Domain walls propagate faster than in fully anisotropic wires below a critical field.

Beyond the critical field, precessional motion reduces velocity.

Abstract

Under a magnetic field along its axis, domain wall motion in a uniaxial nanowire is much slower than in the fully anisotropic case, typically by several orders of magnitude (the square of the dimensionless Gilbert damping parameter). However, with the addition of a magnetic field transverse to the wire, this behaviour is dramatically reversed; up to a critical field strength, analogous to the Walker breakdown field, domain walls in a uniaxial wire propagate faster than in a fully anisotropic wire (without transverse field). Beyond this critical field strength, precessional motion sets in, and the mean velocity decreases. Our results are based on leading-order analytic calculations of the velocity and critical field as well as numerical solutions of the Landau-Lifshitz-Gilbert equation.