title: Stochastic formation of magnetic vortex structures in asymmetric disks triggered by chaotic dynamics.
abstract: The non-trivial spin configuration in a magnetic vortex is a prototype for fundamental studies of nanoscale spin behaviour with potential applications in magnetic information technologies. Arrays of magnetic vortices interfacing with perpendicular thin films have recently been proposed as enabler for skyrmionic structures at room temperature, which has opened exciting perspectives on practical applications of skyrmions. An important milestone for achieving not only such skyrmion materials but also general applications of magnetic vortices is a reliable control of vortex structures. However, controlling magnetic processes is hampered by stochastic behaviour, which is associated with thermal fluctuations in general. Here we show that the dynamics in the initial stages of vortex formation on an ultrafast timescale plays a dominating role for the stochastic behaviour observed at steady state. Our results show that the intrinsic stochastic nature of vortex creation can be controlled by adjusting the interdisk distance in asymmetric disk arrays.
authors.affiliation: 1] Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, Korea.
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Im
authors.affiliation: School of Materials Science and Engineering, KIST-UNIST Ulsan Center for Convergent Materials, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea.
authors.forename: Ki-Suk
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, 20355 Hamburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Vogel
authors.affiliation: Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, Korea.
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Hong
authors.affiliation: 1] Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, 20355 Hamburg, Germany [2] Hamburg Centre for Ultrafast Imaging, University of Hamburg, 22761 Hamburg, Germany [3] Max-Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Meier
authors.affiliation: 1] Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] Physics Department, University of California, Santa Cruz, California 94056, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Fischer