Spin-current-mediated gap solitons in YIG/Pt magnonic crystal

Abstract The main features of the nonlinear pulse propagation in a 100 nm-thick yttrium iron garnet magnonic crystal patterned with a periodic array of platinum surface nanostripes are studied. Experimental and theoretical results demonstrate that the spin current (SC) generated within the Pt layer allows to control the conditions of the formation of spin-wave gap solitons (GSs) in the adjacent yttrium iron garnet film. Gap soliton formation occurs exclusively when the excitation frequency resides within the bandgap (BG) of the magnonic crystal. A critical finding is the downward frequency shift of this BG under increasing SC density in the Pt layer. The investigation further reveals the existence of a threshold power for GSsgeneration, with this threshold exhibiting an inverse dependence on the duration of the input microwave pulse.