Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 9: Magnetic domain walls
MA 9.7: Vortrag
Montag, 12. März 2018, 16:45–17:00, EB 202
Monte-Carlo approach to ferrotoroidic domains in artificial crystals — •Amadé Bortis1, Peter Derlet2, Jannis Lehmann1, Thomas Lottermoser1, and Manfred Fiebig1 — 1Department of Materials, ETH Zürich, Switzerland — 2Paul Scherrer Institute, Villigen PSI, Switzerland
Amongst the primary ferroic orders, ferrotoroidicity is least investigated and understood. Ferrotoroidic systems are defined by a chiral arrangement of magnetic moments which can be associated to a toroidic order parameter. Due to the scarcity of materials which show ferrotoroidicity on a microscopic scale, artificial crystals can be used to reproduce ferrotoroidic order on the mesoscale. These artificial nanomagnetic arrays consist of magnetic islands which are coupled through magnetic-dipole interactions. This implies that the interactions are well defined and tunable, allowing for geometric arrangements which show ferrotoroidic order. The magnetic islands can be modeled as classical Ising spins, which makes kinetic Monte-Carlo simulations (KMC) an efficient tool to investigate the formation of toroidic domains. Domain formation in these systems generally depends on the growth rate and the geometry which determines the strength of the dipolar interactions. We use KMC to understand the correlation of toroidic domains and domain walls as a function of the geometry. We find that the relative coupling strengths in between the islands determines the specific arrangement of the domain walls as well as the the average domain size. Our work provides new insights towards the understanding of ferrotoroidic domains and how they may be tuned.