Nonlinear spin pumping induced by parametric excitation

Abstract

Spin pumping driven by parametric spin excitation was observed in a Pt/La:Y3Fe5O12 film. We applied microwave with doubled frequency of the ferromagnetic resonance and detected a spin current emitted from the La:Y3Fe5O12 layer using the inverse spin-Hall effect (ISHE) in the Pt layer. In the ISHE signal, we found nonlinear dependence and threshold with respect to applied microwave power, demonstrating that the spin current generation is due to nonlinear coupling between microwave and spin dynamics. These results will be essential for developing active elements in spin current circuits. © 2011 American Institute of Physics.