Ultrasonic triggering of giant magnetocaloric effect in MnAs thin films

TL;DR

This paper demonstrates that surface acoustic waves can trigger a giant magnetocaloric effect in MnAs thin films, enabling dynamic control of magnetic properties with potential applications in caloritronics and spintronics.

Contribution

It introduces ultrasonic triggering of the magnetocaloric effect in MnAs thin films, revealing a new method for dynamic magnetic control in semiconductor technology.

Findings

Ultrasound at 170 MHz strongly attenuates during MnAs phase transition.

Giant magnetocaloric effect causes significant ultrasound attenuation.

Anelastic model describes temperature and magnetic field dependence.

Abstract

Mechanical control of magnetic properties in magnetostrictive thin films offers the unexplored opportunity to employ surface wave acoustics in such a way that acoustic triggers dynamic magnetic effects. The strain-induced modulation of the magnetic anisotropy can play the role of a high frequency varying effective magnetic field leading to ultrasonic tuning of electronic and magnetic properties of nanostructured materials, eventually integrated in semiconductor technology. Here, we report about the opportunity to employ surface acoustic waves to trigger magnetocaloric effect in MnAs(100nm)/GaAs(001) thin films. During the MnAs magnetostructural phase transition, in an interval range around room temperature (0{\deg}C - 60{\deg}C), ultrasonic waves (170 MHz) are strongly attenuated by the phase coexistence (up to 150 dB/cm). We show that the giant magnetocaloric effect of MnAs is responsible of the observed phenomenon. By a simple anelastic model we describe the temperature and the external magnetic field dependence of such a huge ultrasound attenuation. Strain-manipulation of the magnetocaloric effect could be a further interesting route for dynamic and static caloritronics and spintronics applications in semiconductor technology.