Magnetic soliton dynamics driven by spin-transfer torque in perpendicular magnetic anisotropy devices

摘要

This paper demonstrates how to excite a complex soliton mode in nanomagnets with perpendicular to plane magnetic anisotropy by means of the non-uniform injection of a spin-polarized current via a nano-aperture. We present two different numerical frameworks. In the first one, the polarizer has perpendicular anisotropy, the excited mode exhibits oscillation frequency in the GHz range with a spatial distribution localized near the nano-aperture. The study of the topological density indicates that the persistent magnetization dynamics is characterized by a rotation of two bubble/antibubble pairs.udThe second scenario corresponds to the experimental framework by [S. M. Mohseni, et al, Science, 339, 1295, (2013).], where the polarizer has an in-plane anisotropy polarizer whose magnetization is tilted under the action of a large external field. Our study identifies the topological density of the dissipative droplet formed in that geometry as a bubble/antibubble pair.udThe methodological study introduced here for the spintronic oscillators and based on the time domain evolution of the topological density should be very useful in the fundamental understanding of the soliton dynamics.