Effects of spin torque within ferromagnetic infinite medium: The short-wave approximation and Painlevé analysis

In this paper, we investigate the effects of spin-transfer torques within the ferromagnetic infinite medium through the short-wave approximation method. As a result, we have derived the new (1+1) dimensional nonlinear evolution system, which describes the propagation of electromagnetic short waves within the ferromagnet in the presence of electric current density. Using the Painlevé analysis and Hirota's bilinearization, we unearth the integrability properties of this new evolution system. In the wake of such an analysis, the typical class of excitations and its physical implications are presented. We remark that the current density acts on magnetization like an effective magnetic damping, which is important for the stabilization of magnetic information storage and data process elements.