Suchergebnisse

The magnetization reversal of each individual layer in magnetic trilayers (permalloy/NdCo/GdCo) is investigated in detail with x-ray microscopy and micromagnetic calculations. Two sequential inversion mechanisms are identified. First, magnetic vortex-antivortex pairs move along the field direction while inverting the magnetization of magnetic stripes until they are pinned by defects. The vortex-antivortex displacements are reversible within a field interval which allows their controlled motion. Second, as the reversed magnetic field increases, cycloidal domains appear in the permalloy layer as a consequence of the dissociation of vortex-antivortex pairs due to pinning. The field range where magnetic vortices and antivortices are effectively guided by the stripe pattern is of the order of tens of mT for the NiFe layer, as estimated from the stability of cycloid domains in the sample. ; Work supported by Spanish MINECO [Grants No. FIS 2013-45469 and No. FIS2016-76058 (AEI/FEDER,EU)] and by FICYT-Asturias (Grant No. FC-GRUPIN14-040). We thank J. Avila (Alba staff) for assistance in the pulsed magnetic field set up. We thank Unidad de Medidas magnéticas y RMN de Sólidos de los Servicios Cientifico Técnicos of Universidad de Oviedo for the VSM characterization. A.H.-R. acknowledges the support from European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie Grant No. H2020-MSCAIF-2016-746958. ; Peer Reviewed