Massively parallel atomistic simulation of ultrafast thermal spin dynamics of a permalloy vortex

TL;DR

This paper uses large-scale atomistic simulations to study ultrafast thermal spin dynamics in a permalloy vortex, revealing complex edge spin wave behavior and long-lived oscillations after laser excitation.

Contribution

It introduces a massively parallel atomistic simulation approach to investigate ultrafast thermal spin dynamics in topological magnetic structures, advancing beyond continuum models.

Findings

Short timescale dynamics resemble bulk behavior.

Edge spin waves induce complex evolution and oscillations.

Long-lived nanosecond oscillations observed.

Abstract

Ultrafast magnetization dynamics probes the most fundamental properties of magnetic materials, exploring questions about the fundamental interactions responsible for magnetic phenomena. Thermal effects are known to be extremely important for laser-induced dynamics in metallic systems, but the dynamics of topological magnetic structures are little understood. Here we apply a massively parallel atomistic spin dynamics simulation to study the response of a permalloy vortex to a 50 fs laser pulse. We find that macroscopically the short timescale dynamics are indistinguishable from the bulk, but that strong edge spin waves lead to a complex time evolution of the magnetic structure and long-lived oscillations on the nanosecond timescale. In the near future such simulations will provide unprecedented insight into the dynamics of magnetic materials and devices beyond the approximations of continuum micromagnetics.