Reversal of ferromagnetic nanotubes
In the last years, the study of ferromagnetic nanotubes has been of much interest due to the physical properties that their cylindrical geometry offers for application in spintronics and biotechnology. For example, they can be used as racetrack memories or logic gates. In this context, it has been necessary to understand the dynamics of reversing the nanotubes magnetisation, where the usual method is to apply magnetic fields. A recent technique has been proposed to assist this process by applying an electric current through the nanotube inner core, which decreases the magnitude of the critical field to reverse its magnetisation . However, applying strong currents increases the material temperature due to the Joule heating. In this project, we propose a variation of this technique by applying weak current pulses at specific frequencies which can effectively help to reverse the nanotube magnetisation.
Our research is based on computational simulations of these long magnetic tubes. Simulating magnetic materials is possible by dividing a material into units of a few nanometres of length. Since the nanotubes are usually a few micro-metres long, intensive computational calculations are required to recreate the dynamics of a whole system. For our calculations, we use a software developed at the University which we have extended to be used on the Iridis supercomputer. This allows us to compute the dynamics of nanotubes on the time scale of a few nanoseconds.
 J. A. Otálora, D. Cortés-Ortuño, D. Görlitz, K. Nielsch, and P. Landeros. Journal of Applied Physics 117, 173914 (2015)
Simulation software: Finmag
Visualisation and data handling software: Mayavi
Computational platforms: Iridis