Ultrafast dynamical path for the switching of a ferrimagnet after femtosecond heating

TL;DR

This paper demonstrates through simulations that ultrafast laser heating can switch ferrimagnetic magnetization by transferring angular momentum between magnetization components, leading to rapid precession on the nanoscale.

Contribution

It reveals the specific dynamical path involving angular momentum transfer necessary for ultrafast magnetic switching in ferrimagnets, using atomistic and Landau-Lifshitz-Bloch models.

Findings

Angular momentum transfer from longitudinal to transverse magnetization is essential.

Switching involves ultrafast precession driven by inter-sublattice exchange.

The dynamical path occurs on the nanoscale during femtosecond heating.

Abstract

Ultrafast laser-induced magnetic switching in rare earth, transition metal ferrimagnetic alloys has recently been reported to occur by ultrafast heating alone. Using atomistic simulations and a ferrimagnetic Landau-Lifshitz-Bloch formalism, we demonstrate that for switching to occur it is necessary that angular momentum is transferred from the longitudinal to transverse magnetization components. This dynamical path leads to magnetization switching and subsequent ultrafast precession caused by the inter-sublattice exchange field on the nanoscale.