Amplification and stabilization of large-amplitude propagating spin waves by parametric pumping

The interaction of a localized parametric pumping with spin waves of different amplitudes, propagating in a ferromagnetic nanowire, is studied analytically and by micromagnetic simulations. It is shown that parametric amplification of spin waves by localized pumping becomes less efficient with an increase in the spin wave amplitude due to the influence of nonlinear 4-magnon processes. In a certain range of spin wave amplitudes, the parametric amplifier acts as a stabilizer of the spin wave amplitude, as its action significantly reduces the spread of the spin wave amplitude in the vicinity of a certain mean value. The stabilization effect becomes more pronounced for higher pumping strength and larger relative lengths of the pumping localization region, compared to the spin wave mean free path. In contrast, the use of relatively short pumping localization regions allows one to efficiently amplify large-amplitude nonlinear spin waves. Published by AIP Publishing.