Excitation of spin waves in superconducting ferromagnets

A theoretical analysis of propagation of spin waves in a superconducting ferromagnet was presented. The surface impedance for the case when the magnetization was normal to the sample surface was also calculated. It was found that the frequencies at which the impedance and the power absorption have singularities related to the spin-wave propagation. It was observed that there was a frequency interval in which two propagating spin waves of the same circular polarization were generated and one of them having a negative group velocity. It was demonstrated that propagating spin waves were possible in superconducting ferromagnets in the Meissner state, similar to those in insulating ferromagnets.