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MA: Fachverband Magnetismus

MA 25: Magnetic Imaging

MA 25.1: Vortrag

Mittwoch, 18. März 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).