Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 62: Magnetic Imaging (Experimental Techniques)

MA 62.6: Vortrag

Freitag, 24. März 2017, 11:00–11:15, HSZ 403

Soft magnetic sensors for the visualization of supercurrents — •Claudia Stahl¹, Stephen Ruoß¹, Julian Simmendinger¹, Joachim Gräfe¹, Markus Weigand¹, Gisela Schütz¹, and Joachim Albrecht² — ¹Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany — ²Research Institute for Innovative Surfaces, FINO, Aalen University, Beethovenstr. 1, 73430 Aalen, Germany

In this work soft ferromagnetic thin Co₄₀Fe₄₀B₂₀ films are utilized as sensor layers on top of the superconductor YBa₂Cu₃O_7−δ in order to map the current density distribution. For highest spatial and magnetic resolution we use scanning x-ray microscopy based on the XMCD (x-ray magnetic circular dichroism) effect [1]. We show the correlation between the topography of the sample and the pinning scenario of magnetic flux in the superconductor using the high spatial resolution of x-ray microscopy and the magnetic contrast of the sensor layer [2]. The x-ray measurements are carried out at our scanning x-ray microscope MAXYMUS at Bessy II, HZB Berlin with the new low temperature setup.

As quick and easy accessible alternative and supplement, low temperature laser-MOKE (magneto-optical Kerr-effect) and FORC (first order reversal curve) [3] analysis of the superconductor/ferromagnet bilayers are conducted. These measurements are used to analyze the eligibility of different sensor materials as well as to complement the x-ray images. [1] APL 106, 022601 (2015). [2] New J. Phys. 18, 103044 (2016). [3] Rev. Scient. Instrum. 85, 023901 (2014).