Magnetic skyrmions in chiral multilayers

In this project we will study magnetic skyrmions, nanoscale swirls of spins that possess a non-trivial topology. They appear in properly designed magnetic multilayers at room temperature and are candidates for next-generation data storage technology. It is now over a decade since the carbon footprint of the internet grew larger than that of commercial air travel, much of this energy is used to physically spin hard disks, write data to them, and write and refresh volatile memory. To drive skyrmions along a crystal using spin torque requires several orders of magnitude less current density then driving magnetic domains under ideal conditions, but this is not seen in practice in these systems so far. Magnetic skyrmions offer the prospect of vastly reducing the energy needed to write and store digital data if their properties can be controlled.
The proposed focus of this project is the mobility of skyrmions at room temperature under the influence of enhanced spin-orbit torques provided by placing the skyrmion-bearing multilayer on top of another material with suitable properties. The student will grow the heterostructures, characterise them structurally and magnetically, and then pattern them into nanoscale devices in which the high current densities needed to generate spin-torques can be achieved with reasonable currents. Skyrmion nucleation and motion will then be studied by means of magnetic imaging.