Propagation and control of nano-scale, magnetic droplet solitons

TL;DR

This paper demonstrates how external magnetic fields can be used to accelerate, stabilize, and control the propagation of nano-scale magnetic droplet solitons in ferromagnetic materials, highlighting their potential for spintronic information transfer.

Contribution

It introduces a theoretical framework combining soliton perturbation theory and micromagnetic simulations to control magnetic droplet solitons with external magnetic fields.

Findings

Magnetic field gradients accelerate stationary solitons.

Uniform control fields stabilize solitons without spin torque.

Propagation distances can reach approximately 10 micrometers.

Abstract

The propagation and controlled manipulation of strongly nonlinear, two-dimensional solitonic states in a thin, anisotropic ferromagnet are theoretically demonstrated. It has been recently proposed that spin-polarized currents in a nanocontact device could be used to nucleate a stationary dissipative droplet soliton. Here, an external magnetic field is introduced to accelerate and control the propagation of the soliton in a lossy medium. Soliton perturbation theory corroborated by two-dimensional micromagnetic simulations predicts several intriguing physical effects, including the acceleration of a stationary soliton by a magnetic field gradient, the stabilization of a stationary droplet by a uniform control field in the absence of spin torque, and the ability to control the soliton's speed by use of a time-varying, spatially uniform external field. Soliton propagation distances approach 10 $\mu$m in low loss media, suggesting that droplet solitons could be viable information carriers in future spintronic applications, analogous to optical solitons in fiber optic communications.