title: Topology and origin of effective spin meron pairs in ferromagnetic multilayer elements.
abstract: We report on pairs of converging-diverging spin vortices in Co/Rh/NiFe trilayer disks. The lateral magnetization distribution of these effective spin merons is directly imaged by means of element-selective x-ray microscopy. By this method, both the divergence and circulation states of the individual layers are identified to be antisymmetric. Reversal measurements on corresponding continuous films reveal that biquadratic interlayer exchange coupling is the cause for the effective meron pair formation. Moreover, their three-dimensional magnetization structure is determined by micromagnetic simulations. Interestingly, the magnetic induction aligns along a flux-closing torus. This toroidal topology enforces a symmetry break, which links the core polarities to the divergence configuration.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany. s.wintz@hzdr.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wintz
authors.forename: Christopher
authors.initials: C
authors.lastname: Bunce
authors.forename: Andreas
authors.initials: A
authors.lastname: Neudert
authors.forename: Michael
authors.initials: M
authors.lastname: Körner
authors.forename: Thomas
authors.initials: T
authors.lastname: Strache
authors.forename: Matthias
authors.initials: M
authors.lastname: Buhl
authors.forename: Artur
authors.initials: A
authors.lastname: Erbe
authors.forename: Sibylle
authors.initials: S
authors.lastname: Gemming
authors.forename: Jörg
authors.initials: J
authors.lastname: Raabe
authors.forename: Christoph
authors.initials: C
authors.lastname: Quitmann
authors.forename: Jürgen
authors.initials: J
authors.lastname: Fassbender