Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 45: Spin Structures at Surfaces and in thin films I (Skyrmions)

MA 45.12: Vortrag

Donnerstag, 3. April 2014, 18:00–18:15, BEY 118

Skyrmion states in triangular-lattice Heisenberg antiferromagnet with frustrated interactions — •Andrey Leonov and Maxim Mostovoy — Zernike Institute for Advanced Materials, University of Groningen, Groningen, 9700AB, The Netherlands

In geometrically frustrated magnets with the triangular lattice, the interplay between nearest- and next-nearest neighbor interactions can stabilize a variety of interesting multi-q phases including the skyrmion crystal state. The spin structure of these skyrmions is somewhat different from that of skyrmions induced in magnets with a non-centrosymmetric lattice by the Dzyaloshinskii-Moriya (DM) interaction, which has lead to difference in static and dynamic properties of these two types of skyrmions. In particular, the DM skyrmions repel each other, whereas the skyrmions on the triangular lattice show the long-ranged attraction that leads to the formation of metastable skyrmion clusters and may stabilize the skyrmion liquid state. In addition, the skyrmions in frustrated systems have more low-energy degrees of freedom and can carry the topological charge and chirality of either sign for a fixed external magnetic field. We applied Monte Carlo simulations to study the rich magnetic field phase diagram of a frustrated triangular antiferromagnet with a uniaxial anisotropy. Using the Landau-Lifshitz-Gilbert equation, we also studied dynamical properties of isolated skyrmions, skyrmion pairs and skyrmion crystals, such as the excitation of collective modes of these systems with time-dependent external magnetic fields and currents.