STUDY OF PARALLEL PUMPING IN MICROWAVE FERRITES.
STANFORD UNIV CALIF MICROWAVE LAB
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The purpose of this study was to investigate the degenerate parallel pumping of the ferromagnetic resonance in microwave ferrites. The investigation is divided mainly into two categories one, the investigation for the pump strength below the instability threshold, and the other above the threshold. Because nonlinearities of the system are not important for the first case, the linearized equation is used for the derivation of the transverse susceptibility under the parallel pump condition. It was found from the analysis that the effective transverse linewidth under the degenerate parallel pump condition is a function of the pump strength and that the effective transverse susceptibility is a function of the pump strength as well as a function of the phase angle between the parallel pump field and the transverse driving field. When the phase angle is chosen for pumping the system at special angles, the system is depumped instead of pumped the effective susceptibility becomes infinite at the threshold of the parallel field. When the parallel field strength is above the threshold, the effective susceptibility becomes negative and hence the system becomes unstable.