Fast Vortex Core Switching at Moderate Temperatures

K.M. Lebeckia and U. Nowak aNanotechnology Centre, VSB-Technical University of Ostrava, 17. listopadu 15, CZ-708 33 Ostrava, Czech Republic bDepartment of Physics, University of Konstanz, D-78457 Konstanz, Germany

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Ferromagnetic vortex core switching is investigated using micromagnetic simulations. For that the OOMMF program is used together with a temperature extension we have developed recently. This is a continuum micromagnetic approach, where the well-known Landau-Lifshitz-Gilbert equation (valid for zero temperature) is replaced by the Landau-Lifshitz-Bloch equation. In our research we simulate switching of a ferromagnetic vortex core in a flat disk (diameter 200 nm, thickness 20 nm) with material parameters that resemble permalloy. Temperatures in the range 400 K to 700 K are considered. Switching itself is caused by application of a very short oscillating magnetic pulse. Parameters used resemble conditions met in the experiment: oscillation period 141 ps (equal to the peak width) and amplitude 60 mT. Surprisingly, no large temperature- or discretization dependence is found. Reasons for that are discussed.

DOI: 10.12693/APhysPolA.127.342 PACS numbers: 75.30.Ds, 75.60.Nt, 75.78.-n, 75.78.Cd