Microscopic formulation of nonlinear spin current induced by spin pumping

Kameda, Mai*; Hirobe, Daichi*; Daimon, Shunsuke*; Shiomi, Yuki*; Takahashi, Saburo*; Saito, Eiji

Nonlinear effects of spin pumping have been investigated by numerically calculating the temporal evolution of the magnon number affected by three- and four-magnon interactions. We showed that the three-magnon interaction gives rise to the enhancement of spin-pumping spin current. We also found that the four-magnon interaction in combination with the three-magnon interaction can be responsible for the experimentally observed low-frequency oscillation of spin current.