Excitations of nonlinear ferromagentic resonance and standing spin wave using inhomogenous high-power RF magnetic field

The resonant precession of the magnetizations such as the ferromagnetic resonance (FMR) and spin wave (SW) excitation is unique and attractive property of the ferromagnetic thin film for future applications in nano-electric and telecommunication devices. Especially, after establishing the concept of the spin current, the considerable attention has been paid to such spin dynamics. Moreover, the oscillation amplitude in such resonant spin motion is found to show the nonlinear responses under the high power excitation. These fascinating properties may open novel functional spintronic devices such as spin current amplifier and neuromophic operation. However, experimental difficulties and complicated spatial spin distribution make it difficult to understand the related phenomena deeply. In this presentation, we show that nonlinear responses for the FMR and the surface SW in a Permalloy strip can be simply excited by the application of non-uniform RF magnetic field with high amplitude.