Elena Vedmedenko (Institute of Applied Physics, University of Hamburg, Germany)

Vortex and Skyrmion Lattices on Periodic and Aperiodic Tilings

Abstract:
   The type of magnetic ordering determines macroscopic physical properties of a system. Especially interesting phenomena emerge in systems with noncollinear spin structures as the noncollinearity strongly influences the dynamical and hysteretic behavior of a magnet [1]. In dependence on the involved interactions the noncollinear magnetism arises at different length scales. For example, on the atomic length scale the magnetic noncollinearity has been reported for systems with competing ferro- and antiferromagnetic interactions [2]; patterns of nanometer large periodicity can appear in magnets with short-range antiferromagnetic and long-range dipolar interactions [3]; while the micrometer large patterns have been found in magnetic arrays of intrinsically collinear nanoparticles [4]. An especially interesting subclass of the non-collinear structuring; i.e., formation of regular vortex arrangements has been found on the geometrically frustrated lattices. Peculiarities of this kind of noncollinear magnetic order will be discussed on examples of antiferromagnetic monolayers with dipolar interactions and magnetostatically coupled magnetic arrays.

[1] E. Y. Vedmedenko, Competing Interactions and Patterns in Nanoworld, Wiley-VCH, Berlin (2007).
[2] M. Bode, E. Y. Vedmedenko, K. von Bergmann, S. Heinze, A. Kubetzka, and R. Wiesendanger, Atomic Spin Structure of Domain Walls in the Antiferromagnetic Fe Monolayer on W(001), Nature Materials, 5, 477-481 (2006).
[3] P. Ferriani, K. von Bergmann, E. Y. Vedmedenko, S. Heinze, M. Bode, M. Heide, G. Bihlmayer, S. Blugel, and R. Wiesendanger, Atomic scale spin spiral with unique rotational sense, Phys. Rev. Lett., 101, 027201 (2008).
[4] E. Y. Vedmedenko, N. Mikuszeit, H.P. Oepen, and R. Wiesendanger, Multipolar Ordering and Magnetization Reversal in Two-Dimensional Nanomagnet Arrays, Phys. Rev. Lett. 95, 207202 (2005).