Imaging flux distributions around superconductors: Geometrical susceptibility in the Meissner state

International audienceExperiment and analytical calculations show that the demagnetizing field of a superconductor is a sensitive probe of quantities otherwise difficult to measure, such as the sample-probe distance in flux-density imaging experiments, and the field of first flux penetration Hp. In particular, the ratio of the maximum field measured above the superconductor edge and the applied field can be determined unambiguously so as to define a linear "geometric" susceptibility. The evolution of this susceptibility with field depends on the regime of flux penetration, and can be used as a means to determine Hp and the effect of a parallel field component in magneto-optical imaging experiments

Imaging flux distributions around superconductors: Geometrical susceptibility in the Meissner state

Under the terms of the Creative Commons Attribution 3.0 Unported License.Experiment and analytical calculations show that the demagnetizing field of a superconductor is a sensitive probe of quantities otherwise difficult to measure, such as the sample-probe distance in flux-density imaging experiments and the field of first flux penetration Hp. In particular, the ratio of the maximum field measured above the superconductor edge and the applied field can be determined unambiguously so as to define a linear >geometric> susceptibility. The evolution of this susceptibility with field depends on the regime of flux penetration and can be used as a means to determine Hp and the effect of a parallel field component in magneto-optical imaging experiments. © 2013 AIP Publishing LLC.A. Badía acknowledges funding by the Spanish MINECO and the European FEDER Program (Projects MAT2011-22719, ENE2011-29741) and by Gobierno de Aragón (Research group T12). We are grateful to D. Colson and A. Forget of the CEA-IRAMIS-SPEC for providing the Ba(Fe0.925Co0.075)2As2 crystals. C. J. van der Beek acknowledges support from the MagCorPnic grant of the Triangle de la Physique du Plateau de Saclay.Peer Reviewe