Ultrafast Local Magnetization and Demagnetization in Heusler Alloys

TL;DR

This paper demonstrates ultrafast local magnetization and demagnetization in Heusler alloys driven by laser pulses, revealing tunable spin transfer mechanisms on femtosecond timescales using ab-initio simulations.

Contribution

It introduces a detailed ab-initio simulation approach to understand ultrafast spin dynamics and identifies the role of density of states in sublattice spin transfer in Heusler compounds.

Findings

Local magnetic moments can change within a few femtoseconds.

Spin transfer between sublattices depends on laser parameters.

Density of states explains the observed spin dynamics.

Abstract

With the goal of pushing Spintronic devices towards faster and faster timescales, we demonstrate, using ab-intio time-dependent density functional theory simulations of bulk Heusler compounds subject to ultrashort intense laser pulses, that the local magnetic moment can increase or decrease in a few femtoseconds. This speed is due to the all optical nature of the process, which transfers spin moment from one sublattice to another. This transfer depends on easily tunable laser parameters. By comparing the spin dynamics of a variety of Heusler (or half-Heusler) compounds, we demonstrate that the density of states explains the observed moment transfer; most the physics of inter sublattice moment transfer is due to the flow of spin current which is governed by availability of states above the Fermi level.