The research group of Yan Zhou use micromagnetic modelling with the well-established Object Oriented MicroMagnetic Framework (OOMMF). They investigate the skyrmion dynamics driven by spin waves in constricted geometries with the Dzyaloshinskii-Moriya interaction. For example, in nanotracks, L-corners, and T- and Y-junctions (see figure), which are the basic ingredients of circuits based on skyrmions.

Skyrmion travel

The group’s results show that a skyrmion can travel quite a long distance without touching the sample edges and without requiring fine-tuning of the sample parameters. They show that a skyrmion can turn around a shaped corner without touching the sample edges even in the case of the L-corner. It is also found that a skyrmion always turns left (or right) at the T- or Y-junctions when the topological number is positive (or negative).

Controlling direction

The turning direction of the skyrmion at the junction can be controlled by using multiple spin wave injection sources. In addition, the skyrmion velocity can be well explained by a fitting function, which embodies its initial acceleration and subsequent exponential decay. These new results will pave a way to future applications to skyrmionics, and will be the basis of skyrmion-based devices driven by spin waves.

More information about this research can be found in the journal Nanotechnology 26 225701.

Further reading

Dual-tips improve magnetic-field imaging at the nanoscale (Jan 2015)
Hybrid nanostructures: a novel way to control domain walls (May 2015)
Tunnelling electroresistance in multiferroic heterostructures (Dec 2014)