Mechanical Bistability in Kerr-modified Cavity Magnomechanics

TL;DR

This paper reports the observation of mechanical bistability in a cavity magnomechanical system, driven by strong microwave fields, where Kerr nonlinearities significantly alter the system's behavior, revealing new nonlinear phenomena.

Contribution

It introduces the first measurement of magnon-phonon cross-Kerr nonlinearity and demonstrates Kerr-type nonlinearities' role in mechanical bistability within cavity magnomechanics.

Findings

Observation of mechanical bistability in the system.

First measurement of magnon-phonon cross-Kerr nonlinearity.

Kerr nonlinearities significantly modify cavity magnomechanics.

Abstract

Bistable mechanical vibration is observed in a cavity magnomechanical system, which consists of a microwave cavity mode, a magnon mode, and a mechanical vibration mode of a ferrimagnetic yttrium-iron-garnet (YIG) sphere. The bistability manifests itself in both the mechanical frequency and linewidth under a strong microwave drive field, which simultaneously activates three different kinds of nonlinearities, namely, magnetostriction, magnon self-Kerr, and magnon-phonon cross-Kerr nonlinearities. The magnon-phonon cross-Kerr nonlinearity is first predicted and measured in magnomechanics. The system enters a regime where Kerr-type nonlinearities strongly modify the conventional cavity magnomechanics that possesses only a radiation-pressure-like magnomechanical coupling. Three different kinds of nonlinearities are identified and distinguished in the experiment. Our work demonstrates a new mechanism for achieving mechanical bistability by combining magnetostriction and Kerr-type nonlinearities, and indicates that such Kerr-modified cavity magnomechanics provides a unique platform for studying many distinct nonlinearities in a single experiment.