Berlin 2018 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 17: Skyrmions III (joint session MA/TT/KFM)

KFM 17.5: Vortrag

Mittwoch, 14. März 2018, 16:00–16:15, EB 301

Critical Phenomena in Confined Skyrmion Systems — •Jonathon Waters¹, Timothy Sluckin¹, Denis Kramer¹, Hans Fangohr², and Ondrej Hovorka¹ — ¹University of Southampton, Southampton, UK — ²European XFEL, Germany

There have been extensive studies which establish the magnetic phases and quantify the thermal phase transition behaviour in bulk helimagnetic materials. However, many proposed device applications, which will utilise the skyrmion phase of these materials, are expected to assume operation in confined geometries and, therefore, it is critical to access the role of the confinement and finite size effects on the stability of skyrmion phases. So far, there have been few studies aimed at understanding the finite system size effects on the thermal phase transition behaviour in these systems. This presentation will discuss our recent developments of systematic analysis of these fundamental effects.

We present large-scale Monte-Carlo simulations of cubic nanoparticles, modelled by a general Heisenberg model with Dzyaloshinskii-Moriya interaction (DMI), and establish phase diagrams for different combinations of exchange and DMI strengths. We apply several different annealing protocols when generating the phase diagram in order to establish the role of metastability and hysteresis in the phase behaviour of these systems. Finally we discuss the results of a finite system size scaling analysis and establish the dependence of critical phase transition temperature on the particle size.