Pulse-driven depinning of magnetic gap modes in ferromagnetic films

Abstract

Manipulation of magnons in artificial magnonic crystals (MCs) leads to fascinating nonlinear wave phenomena such as the generation of gap solitons, which has been mostly limited to one-dimensional systems. Here, we propose a model system for the magnetization in two-dimensional MCs subjected to a periodic external magnetic field, describing the dynamics of magnetic gap solitons (MGSs) formed by nonlinear self-trapping. We show the formation, stability, and dynamics for various two-dimensional gap modes, including gap solitons and vortical ones. Their existence regions depend on the anisotropic axis orientation of the ferromagnetic film. The Bloch oscillation and depinning propagation of MGSs under constant spin-current injections are discovered and characterized. We design a scheme of pulse current injection to achieve distortionless propagation of MGSs. These findings show that the 2D magnonic crystals can be viewed as a building block for MGSs-based storage and transmission, where the propagation and localization are variously controlled and reconfigurable.Comment: 7 pages, 5 figure