Little-Parks effect governed by magnetic nanostructures with out-of-plane magnetization

© 2020 The author(s). We want to thank Spanish MICINN Grants FIS2016-76058 AEI/FEDER, UE), EU COST-CA16218. IMDEA Nanociencia acknowledges support from the 'Severo Ochoa' Programme for Centres of Excellence in R&D (MICINN, Grant SEV-2016-0686). MCO and AG acknowledges financial support from Spanish MICINN Grant ESP2017-86582-C4-1-R and IJCI-2017-33991; AMN acknowledges financial support from Spanish CAM Grant 2018-T1/IND-10360.
Little-Parks effect names the oscillations in the superconducting critical temperature as a function of the magnetic field. This effect is related to the geometry of the sample. In this work, we show that this effect can be enhanced and manipulated by the inclusion of magnetic nanostructures with perpendicular magnetization. These magnetic nanodots generate stray fields with enough strength to produce superconducting vortex-antivortex pairs. So that, the L-P effect deviation from the usual geometrical constrictions is due to the interplay between local magnetic stray fields and superconducting vortices. Moreover, we compare our results with a low-stray field sample (i.e. with the dots in magnetic vortex state) showing how the enhancement of the L-P effect can be explained by an increment of the effective size of the nanodots.
Unión Europea. Horizonte 2020
Unión Europea. H2020/COST
Ministerio de Economía y Competitividad (MINECO)/AEI/FEDER
Ministerio de Ciencia e Innovación (MICINN)
Comunidad de Madrid
Centros de Excelencia Severo Ochoa (MICINN)
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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