Nonlinear radiation damping of nuclear spin waves and magnetoelastic waves in antiferromagnets

Parallel pumping of nuclear spin waves in antiferromagnetic CsMnF sub(3) at liquid helium temperatures and magnetoelastic waves in antiferromagnetic FeBO sub(3) at liquid nitrogen temperature in a helical resonator was studied. It was found that the absorbed microwave power is approximately equal to the irradiated power from the sample and that the main restriction mechanism of absorption in both cases is defined by the nonlinear radiation damping predicted about two decades ago. Nonlinear radiation damping is sure to be a common feature of the parallel pumping technique for all normal magnetic excitations and it must be taken into account for interpretation of nonlinear phenomena in parametrically excited magnetic systems.