Nonlinear radiation damping of parametrically excited spin waves

Abstract

We consider the process of microwave parametric excitation of spin waves in a resonator. The interaction of the resonator cavity photon with the parametric magnon pair is expected to cause additional nonlinearity: nonlinear radiation damping which is proportional to the quality factor Q of the resonator. Estimations of this positive nonlinear magnon relaxation in ferromagnets and antiferromagnets (for electronic and nuclear spin waves, magnetoelastic waves) show that it can play an important role in forming the stationary state. The threshold of the autooscillations of microwave absorption in a ferromagnet is found to increase with increasing Q.