Microwave

Quantum mechanics

Optical bistability

Kerr effect

Magnetic field

Magnetization

Materials science

Ferromagnetism

Yttrium iron garnet

Magnon

Laser

Physics

Nonlinear system

Laser linewidth

Optics

Nonlinear optics

Condensed matter physics

Magnetostriction

Ferrimagnetism

Bistability

Microwave cavity

Optoelectronics

Physical Review Letters

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 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 Letter 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.

Mechanical Bistability in Kerr-modified Cavity Magnomechanics