Mode-sensitive magnetoelastic coupling in phononic-crystal magnomechanics

TL;DR

This paper explores how phononic crystal cavities can be used to control spin-wave resonance through magnetoelastic coupling, highlighting mode-dependent effects and potential for scalable magnomechanical circuits.

Contribution

It introduces a novel phononic-crystal cavity design that enables mode-sensitive control of magnetoelastic interactions for spin-wave excitation.

Findings

Confinement of gigahertz vibrations in a defect cavity enables multiple resonance modes.

Inhomogeneous strain distributions influence magnetostrictive coupling.

A monopole-like mode offers subwavelength-scale excitation independent of field angle.

Abstract

Acoustically driven spin-wave resonance in a phononic crystal cavity is numerically investigated. The designed cavity enables confinement of gigahertz vibrations in a wavelength-scale point-defect structure and sustains a variety of resonance modes. Inhomogeneous strain distributions in the modes modify the magnetostrictive coupling and the spin-wave excitation susceptible to an external field orientation. In particular, a monopole-like mode in the cavity having a near-symmetrical pattern shows a subwavelength-scale mode volume and can provide a versatile acoustic excitation scheme independent on field-angle variation. Thus, the phononic-crystal platform offers an alternative approach to acoustically control the spin-wave dynamics with ultrasmall and inhomogeneous mode structures, which will be a key technology to integrate and operate large-scale magnomechanical circuits.