Skyrmion-number dependence of spin-transfer torque on magnetic bubbles

TL;DR

This paper theoretically investigates how the skyrmion number influences the spin-transfer torque on magnetic bubbles, revealing that transverse motion is suppressed as skyrmion number deviates from one.

Contribution

It introduces a theoretical framework for understanding skyrmion-number dependence of spin-transfer torque on magnetic bubbles, highlighting differential effects on bubble motion.

Findings

Transverse motion is suppressed for skyrmion numbers far from one.

Longitudinal motion remains relatively unaffected by skyrmion number.

Skyrmion number can vary depending on magnetic profile and size.

Abstract

We theoretically study the skyrmion-number dependence of spin-transfer torque acting on magnetic bubbles. The skymrion number of magnetic bubbles can take any integer value depending on the magnetic profile on its circumference and the size of the bubble. We find that the transverse motion of a bubble with respect to the charge current is greatly suppressed as the absolute value of skyrmion number departs from unity, whereas the longitudinal motion is less sensitive.