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MA: Fachverband Magnetismus

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

MA 45.4: Talk

Thursday, April 3, 2014, 15:45–16:00, BEY 118

Exotic topologically nontrivial spin structures in systems with competing Dzyaloshinskii-Moriya interaction and four-spin interaction — •Nikolai S. Kiselev, David S. G. Bauer, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Systems of low dimensionality such as monatomic chains, nano-islands and monolayers exhibit unique properties different from bulk materials. In particular, due to the surface/interface induced changes of the electronic properties, monolayers of transition metals show unusual magnetic properties. For instance, the ground state of the Fe/Ir(111) [1] system corresponds to a complex previously unknown spin structure, which we identified as a staggered lattice of chiral meron-animeron pairs. The spin structure in such systems arises due to the interplay of three main energy contributions: Heisenberg exchange, Dzyaloshinskii-Moriya interaction, and four-spin interaction (FSI). We present a three-dimensional magnetic phase diagram (PD) in terms of the applied magnetic field, four-spin interaction coupling constant, and temperature. In this PD we identified the area of existence of the spiral state and the hexagonal lattice of nano skyrmions, which can be stabilized at zero field. We explain mechanism of their stabilization. Generalization of our model explains the emergence of the spiral state and skyrmions in Pd/Fe/Ir(111) [2].

[1] S. Heinze et al., Nature Phys. 7, 713 (2011).

[2] N. Romming et al., Science 341, 636 (2013).