Vortex-antivortex 'molecular crystals' in hybrid ferromagnet/superconductor structures

Simon J Bending, J S Neal, M V Miloevic, A Potenza, L San Emeterio, C H Marrows

Research output: Contribution to journalArticle

Abstract

We have used high resolution Hall probe microscopy to image vortex-antivortex (V-AV) 'molecules' induced in superconducting Pb films by the stray fields from square arrays of ferromagnetic Co/Pt dots. We have directly observed spontaneous V-AV pairs and studied how they interact with added 'free' (anti)fluxons in an applied magnetic field. We observe a rich variety of subtle phenomena arising from competing symmetries in our system which can either drive added antivortices to join AV shells around nanomagnets or stabilise the translationally symmetric AV lattice between the dots. Added vortices annihilate AV shells, leading eventually to a stable 'nulling' state with no free fluxons, which should exhibit a strongly (field-)enhanced critical current. At higher densities we actually observe vortex shells around the magnets, stabilised by the asymmetric anti-pinning potential. Our experimental findings are in good agreement with Ginzburg-Landau calculations.
Original languageEnglish
Article number052019
JournalJournal of Physics: Conference Series
Volume150
Issue number5
DOIs
Publication statusPublished - 2009

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vortices
crystals
superconducting films
critical current
magnets
microscopy
probes
high resolution
symmetry
magnetic fields
molecules

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Vortex-antivortex 'molecular crystals' in hybrid ferromagnet/superconductor structures. / Bending, Simon J; Neal, J S; Miloevic, M V; Potenza, A; San Emeterio, L; Marrows, C H.

In: Journal of Physics: Conference Series, Vol. 150, No. 5, 052019, 2009.

Research output: Contribution to journalArticle

Bending, Simon J ; Neal, J S ; Miloevic, M V ; Potenza, A ; San Emeterio, L ; Marrows, C H. / Vortex-antivortex 'molecular crystals' in hybrid ferromagnet/superconductor structures. In: Journal of Physics: Conference Series. 2009 ; Vol. 150, No. 5.
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