Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 25: Magnetic Imaging
MA 25.1: Talk
Wednesday, March 18, 2015, 09:30–09:45, H 1012
Detecting magnetic flux distributions in superconductors with magnetic scanning x-ray microscopy — •Claudia Stahl1, Stephen Ruoß1, Patrick Audehm1, Markus Weigand1, Gisela Schütz1, and Joachim Albrecht2 — 1Max Planck Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart — 2Forschungsinstitut für Innovative Oberflächen, Hoschschule Aalen, Beethovenst. 1, 73430 Aalen
The magnetic flux distribution arising from a high-Tc superconductor is detected and visualized using polarized x rays. Therefore, we introduce a sensor layer, namely, an amorphous, soft-magnetic Co40Fe40B20 cover layer, providing a large x-ray magnetic circular dichroism (XMCD). CoFeB is directly deposited on top of high-Tc superconducting YBCO structures [1]. The magnetic stray fields of the supercurrents lead to a local reorientation of the magnetic moments in the ferromagnet. Using polarized x-rays it is possible to measure the local magnetization via the XMCD effect.
We show that the XMCD contrast in the sensor layer corresponds to the in-plane magnetic flux distribution of the superconductor [2] and can hence be used to image magnetic structures in superconductors with high spatial resolution.
The measurements are carried out at our scanning x-ray microscope MAXYMUS and our own dedicated reflectometry endstation at Bessy II at HZB in Berlin.
[1] C. Stahl et al., EPL 106, 27002 (2014). [2] C. Stahl et al., PRB 90, 104515 (2014).