Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: POSTER Ia
MA 19.69: Poster
Dienstag, 17. März 2015, 09:30–13:00, Poster A
Stability of Single Skyrmionic Bits — •Julian Hagemeister, Niklas Romming, Kirsten von Bergmann, Elena Y. Vedmedenko, and Roland Wiesendanger — Institute of Applied Physics and Interdisciplinary Nanoscience Center Hamburg, University of Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany
The switching between topologically distinct skyrmionic and ferromagnetic states has been proposed as a bit-operation for information storage. Generally, long lifetimes of the bits in combination with short switching times are required for data storage devices. To study the feasibility of realizing these preconditions for skyrmionic bits, we have investigated their energy landscape in a broad range of magnetic fields and temperatures theoretically by means of classical Monte-Carlo (MC) simulations. A critical field Bc at which the mean lifetimes of the skyrmionic (Sk) and ferromagnetic (FM) states are identical has been identified. Notably, the field dependent mean lifetimes of the two states show a high asymmetry with respect to Bc in contrast to conventional uniaxial magnetic bits. The main reason for the asymmetry has been found to be a different field dependence of the skyrmionic and ferromagnetic activation energies. We were also able to correlate the stability of skyrmions in systems on discrete lattices with their attempt frequency rather than with their activation energy. We use this knowledge to propose a procedure permitting the determination of effective material parameters and the quantification of the MC time scale from the comparison of theoretical and experimental data.