Blowing Magnetic Skyrmion Bubbles

TL;DR

This paper demonstrates how magnetic skyrmion bubbles can be generated and manipulated in solid-state systems using inhomogeneous currents, drawing an analogy to soap bubble formation, with implications for data storage technologies.

Contribution

It introduces a novel method to create and control magnetic skyrmion bubbles via inhomogeneous currents and geometrical constrictions, inspired by topological transitions in soap bubbles.

Findings

Skyrmion bubbles are generated using inhomogeneous in-plane currents.

The phase diagram for skyrmion formation is mapped out.

Skyrmions can be manipulated, including depinning and motion.

Abstract

Soap bubbles form when blowing air through a suspended thin film of soapy water and this phenomenon entertains children and adults alike. The formation of soap bubbles from thin films is accompanied by topological transitions, and thus the natural question arises whether this concept is applicable to the generation of other topological states. Here we show how a magnetic topological structure, namely a skyrmion bubble, can be generated in a solid state system in a similar manner. Beyond enabling the investigation of complex surface-tension driven dynamics in a novel physical system, this observation has also practical implications, since the topological charge of magnetic skyrmions has been envisioned as an information carrier for new data processing technologies. A main goal towards this end is the experimental creation and manipulation of individual mobile skyrmions at room temperature. By utilizing an inhomogeneous in-plane current in a system with broken inversion asymmetry, we experimentally blow magnetic skyrmion bubbles through a geometrical constriction. The presence of a spatially divergent spin-orbit torque gives rise to instabilities of the magnetic domain structures that are reminiscent of Rayleigh-Plateau instabilities in fluid flows. Experimentally we can determine the electric current versus magnetic field phase diagram for skyrmion formation and we reveal the efficient manipulation of these dynamically created skyrmions, including depinning and motion. The demonstrated current-driven transformation from stripe domains to magnetic skyrmion bubbles could provide additional avenues for implementing skyrmion-based spintronics.