Skyrmion elongation, duplication and rotation by spin-transfer torque under spatially varying spin current

TL;DR

This paper investigates how spatially varying spin currents influence skyrmions, demonstrating elongation, duplication, and rotation effects controllable by current pulse parameters, with potential implications for spintronic device manipulation.

Contribution

It introduces a numerical study showing how inhomogeneous spin currents can elongate, split, and rotate skyrmions, revealing new control mechanisms for skyrmion dynamics.

Findings

Inhomogeneous currents cause skyrmion elongation.

Long pulses split skyrmions into two.

Short pulses lead to relaxation and rotation.

Abstract

The effect of the spatially varying spin current on a skyrmion is numerically investigated. It is shown that an inhomogeneous current density induces an elongation of the skyrmion. This elongation can be controlled using current pulses of different strength and duration. Long current pulses lead to a splitting that forms two replicas of the initial skyrmion while for short pulses the elongated skyrmion relaxes back to its initial circular state through rotation in the MHz-GHz frequency range. The frequency is dependent on the strength of the damping coefficient.