Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Superconductivity: Topological Defects in Superconductors and Magnets (joint session TT/MA)
TT 22.10: Vortrag
Montag, 12. März 2018, 17:30–17:45, HFT-FT 101
Domain formation in the type-II/1 superconductor niobium — •Alexander Backs1,2, Tommy Reimann1,2, Michael Schulz1,2, Vitaliy Pipich1,3, Sebastian Mühlbauer1, and Peter Böni2 — 1Heinz Maier-Leibnitz Zentrum, Garching, Germany — 2Physik-Department E21, Technische Universität München, Garching, Germany — 3Jülich Center for Neutron Research, Jülich, Germany
In type-II/1 superconductors, an attractive interaction between single magnetic vortices leads to the formation of a magnetic domain structure, denoted intermediate mixed state (IMS). The IMS is made up of flux free domains and regions containing a vortex lattice (VL) [1].
We have studied the nucleation and morphology of the IMS in the type-II/1 s-wave superconductor niobium [1] [2] with a combination of small and ultra small angle neutron scattering and neutron grating interferometry to gain information about the VL, the IMS domains and their spatial distribution, respectively. In the case of strong pinning, the magnetic structure changes from a homogeneous VL into clustered domains upon field cooling. This phase separation sets in below the freezing transition of the VL, thereby demonstrating how vortex pinning can be overcome on a local scale while macroscopically retaining it. The IMS scattering function shows strong similarities to the model of spinodal decomposition where the usual time dependence is implicit in the cooling process.
E. H. Brandt and M. P. Das, Journal of Superconductivity and Novel Magnetism 24, 57 (2011)
T. Reimann et al., Nat. Commun.6, 8813 (2015)
T. Reimann et al., Phys. Rev. B 96, 144506 (2017)