Dynamical current-induced ferromagnetic and antiferromagnetic resonances

TL;DR

This paper demonstrates how dynamical spin accumulations induced by the spin Hall effect can trigger ferromagnetic and antiferromagnetic resonances in multilayer structures, offering insights for ultrafast spintronics applications.

Contribution

It introduces a framework for controlling magnetic excitations via electric fields in multilayers, revealing mode-specific responses based on magnetic coupling and layer design.

Findings

Out-of-phase mode is excited in ferromagnetically coupled Fe/W/Fe trilayers.

Antiferromagnetically coupled layers exhibit elliptical precession with opposite velocities.

Manipulation of spin-wave modes can enable ultrafast spintronic devices.

Abstract

We demonstrate that ferromagnetic and antiferromagnetic excitations can be triggered by the dynamical spin accumulations induced by the bulk and surface contributions of the spin Hall effect. Due to the spin-orbit interaction, a time-dependent spin density is generated by an oscillatory electric field applied parallel to the atomic planes of Fe/W(110) multilayers. For symmetric trilayers of Fe/W/Fe in which the Fe layers are ferromagnetically coupled, we demonstrate that only the collective out-of-phase precession mode is excited, while the uniform (in-phase) mode remains silent. When they are antiferromagnetically coupled, the oscillatory electric field sets the Fe magnetizations into elliptical precession motions with opposite angular velocities. The manipulation of different collective spin-wave dynamical modes through the engineering of the multilayers and their thicknesses may be used to develop ultrafast spintronics devices. Our work provides a general framework that probes the realistic responses of materials in the time or frequency domain.