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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.

Ferromagnetic Mn5Si3C0.8 and Mn5Ge3C0.8 films with Curie temperatures TC well above room temperature are obtained by C+12-ion implantation in antiferromagnetic Mn5Si3 or ferromagnetic Mn5Ge3. Patterning of the films with a gold mesh serving as a stencil mask during implantation allows a lateral modification of magnetic order creating ferromagnetic regions of Mn5Si3C0.8 which are embedded in antiferromagnetic Mn5Si3. This provides a procedure for the fabrication of magnetoelectronic hybrid devices comprised of different magnetic phases.

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The influence of a nanoscale surface modulation periodicity of ion beam eroded substrates ͑ripples͒ on the interlayer exchange coupling in polycrystalline Fe/Cr/Fe thin films is investigated. Using 22 nm rippled substrates, we find a pronounced Néel coupling superimposed on the interlayer exchange coupling in Fe/Cr/Fe trilayers associated with a strong uniaxial anisotropy induced by the substrate topography. For longer periods the Néel contribution and uniaxial anisotropy become weaker and finally vanish in the case of a flat substrate and film. These results are obtained by applying a Stoner-Wohlfarth model on magnetic reversal loops measured by longitudinal magneto-optical Kerr effect magnetometry.