PGI-1 Seminar: Jacob Gayles
Helicity and size dependence of skyrmions in Mn(1-x)FexGe mediated by the Dzyaloshinskii-Moriya interaction
- 21.Aug.2013 11:30
University of Texas
First-principles electronic structure calculations were carried out for bulk alloys of Mn(1-x)FexGe in the B20 compounds where skyrmions are experimentally observed to vary in size and chiral order. The ground state of the B20 compounds helical spirals form along the <111> direction, where skyrmions form in a nonzero magnetic field with a similar pitch and just below the transition temperature. We employed the Virtual Crystal Approximation to vary the concentration of manganese atoms within the unit cell. Using a first order perturbation approach of the spin-orbit coupling to spin-spiral calculations we observe the Dzyaloshinski-Moriya (DM) vector changes sign and magnitude with the concentration of Mn ions. Within the micro-magnetic model we are able to find helical periods that compare to the experiments. We are also look into the anisotropy of DM interaction as the effect that minimizes the total energy in the <111> direction where the magneto-crystalline anisotropy is very weak in these systems.
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