Magnetization switching by ultrashort acoustic pulses

TL;DR

This paper theoretically demonstrates that ultrashort, few-picosecond acoustic pulses can reverse magnetization in magneto-strictive materials like Terfenol-D by inducing giant magneto-elastic changes, with switching governed by pulse area.

Contribution

It introduces a novel mechanism for magnetization switching using ultrashort acoustic pulses and establishes the importance of pulse area in the switching process.

Findings

Magnetization can be reversed by a single ultrashort acoustic pulse.

Switching threshold depends on the acoustic pulse area.

Simulation results support the feasibility of acoustic pulse-induced magnetization switching.

Abstract

It is shown theoretically that a single a few picoseconds long acoustic pulse can reverse magnetization in a magneto-strictive material Terfenol-D. Following giant magneto-elastic changes of free energy density the magnetization vector is kicked out of a local in-plane energy mininum and decays into another minimum. For acoustic pulse duration significantly shorter than magnetization precession period $\tau_{ac}$<<$T_{prec}$, the switching threshold is determined by the {\it acoustic pulse area}, i.e. pulse integral in time domain, similar to coherent phenomena in optics. Simulation results are summarized in a magneto-acoustic switching diagram and discussed in the context of all-optical magnetization switching by circularly polarized light pulses.