Ideas are bubbling for more efficient computer memory

Skyrmions, discovered just a few years ago, are tiny islands of magnetism that form in certain materials. If you wrapped one up into a sphere, its magnetic fields would point away in all different directions.

Scientists found they could prod these skyrmions to move using electric currents, and an idea was born: could they be used to represent 1s and 0s in computer memory?

Transistors, which form the basis of today’s computing, are tiny devices that stop the flow of electric current. However, there’s a limit to how small these can be made. Scientists want to find a way to create 1 and 0 by using physics phenomena that don’t actually change the atomic structure of the material, for example, making a line of skyrmions that could be read as 1s and 0s.

However, the only way the scientists knew how to make new individual skyrmion bubbles on demand was at very low temperatures with expensive equipment such as spin-polarised scanning tunnelling microscopes.

Instead, the team used a geometric structure to ‘blow’ the bubbles into shape in a very thin film. Using the Center for Nanoscale Materials, a DOE Office of Science user facility at Argonne, they built a constricted wire out of a three-layered structure in which a tiny layer of magnetic material is sandwiched between tantalum and tantalum-oxide layers.

Long stripes of magnetic domains appear in the magnetic material on one side of a tiny channel. When the scientists applied an electric current to the metal layers, the stripes stretched through the channel and broke into tiny spherical skyrmion bubbles on the other side.

The study, Blowing Magnetic Skyrmion Bubbles, was published on 12^th June in Science Express. The research was supported by the U.S. Department of Energy’s Office of Science, Basic Energy Sciences, Materials Science and Engineering, and by the National Science Foundation. The Center for Nanoscale Materials is a DOE Office of Science user facility.