MDR Vacation Bursary Project: Magnetic Skyrmions in thin films
by Luke Goater
By Matthew Corcoran, undergraduate student , Faculty of Engineering and the Environment
I am an undergraduate student studying Mechanical engineering at the University of Southampton. I have just completed my third year of a four year masters course with an advanced materials theme. The chosen research field is micromagnetic simulations. The studied material is usually ferromagnetic and it is the magnetic moments of the material that are of interest with this type of research.
During my third year individual project I investigated magnetic Skyrmions in thin films. This research was carried out using Monte Carlo simulations: these simulations utilises random numbers in the main algorithm of the simulation, they work by random sampling of possible configurations to minimise the energy of a system. Skyrmions are topological stable spin textures, where the magnetic moments carried by the atoms form a special kind of vortex as is shown in the figure. The formation of Skyrmions is attributed to three competing energy terms on neighbouring lattice sites: Exchange, DMI, and Zeeman energy.
One image produced from the results from my project is shown above; the results from this simulation are consistent with other skyrmion simulations. From the image it can be seen that there are 22 skyrmions in the geometry. The centre of the skyrmions points in the opposite direction to the applied magnetic field, toward the reader. The vectors not grouped into a skyrmion have a lower total energy and tend to align in the direction of the applied field. The vectors on the boundary are aligned parallel to the boundary and rotate in an anticlockwise direction. The external magnetic field was 0.4 Tesla and the geometry was 100 nano meters in the x direction 100 meters in the y direction and 1 nano meter in the z direction. The mesh size was 50, 50 and 1 in the x, y and z directions respectfully. This research is being continued over the summer starting with an investigation into Skyrmion hysteresis using Southampton’s own Finmag simulation software.
There appears to be lots of scope for work to extend my summer project, including the exploration of the Skyrmions for data storage. This is an area of research that is just starting to emerge, and it is difficult to predict the range of possible applications at this stage.
Categories: Blog. Tags: advanced materials, epsrc, hans fangohr, magnetic, matthew corcoran, meng mechanical engineering, micromagnetic simulations, nanoscience, nanotechnology, skyrmions, and vacation bursary. Project names: Magnetic Skyrmions in thin films.