Magnetization control by angular momentum transfer from surface acoustic wave to ferromagnetic spin moments

TL;DR

This paper demonstrates that surface acoustic waves' phonon angular momentum can control ferromagnetic magnetization through phononic-to-electronic conversion, opening new avenues for spintronic device functionalities.

Contribution

First experimental demonstration of phonon angular momentum transfer to ferromagnetic spin moments in a Ni/LiNbO3 hybrid device.

Findings

Phonon angular momentum can control ferromagnetic magnetization.

Surface acoustic waves enable angular momentum transfer to spins.

Potential for new spintronic device functionalities.

Abstract

The angular momentum interconversion between electron spin and other type of angular momenta is useful to develop new spintronic functionalities. The conversions from the angular momentum of photon and mechanical rotation to ferromagnetic spin moment have been well studied. While the recent studies theoretically suggested circular vibration of atoms works as angular momentum of phonon, the direct experimental demonstration of conversion to spin moments remains to be performed. Here we demonstrate that the phonon angular momentum of surface acoustic wave can control the magnetization of a ferromagnetic Ni film by means of the phononic-to-electronic conversion of angular momentum in Ni/LiNbO$_3$ hybrid device. This result clearly shows the phonon angular momentum is useful to further fictionalize spintronic devices.