Observation of nonlinear phenomena in ferromagnetic transmission resonance

Abstract

In this paper we present the nonlinear effects we obtained so far through ferromagnetic-transmission-resonance experiments in iron and nickel. The experiments were performed in the geometry in which both the applied and microwave fields are mutually parallel and also parallel to the sample surface at the input cavity. In this geometry, we have found two interesting transmitted waves through ferromagnetic samples several microns thick. One is polarized parallel to and has the same frequency as the applied microwave field. The other, polarized perpendicular to the applied field, has a frequency half that of the applied field and is generated in the ferromagnetic sample. The results are compared to the nonlinear theory presented in the previous paper. The agreement between the experimental and theoretical results is reasonable. The theory shows that the nonlinear phenomena are very sensitive to the exchange stiffness constant. It is thus hoped that these phenomena will be useful in determining the exchange stiffness constant, and ultimately the exchange integral, as a function of temperature. Further, they might provide new information on spin-relaxation processes.