Detecting magnetic flux distributions in superconductors with polarized x rays

Claudia Stahl; Patrick Audehm; Joachim Gräfe; Stephen Ruoß; Markus Weigand; Mathias Schmidt; Sebastian Treiber; Michael Bechtel; Eberhard Goering; Gisela Schütz; Joachim Albrecht

doi:10.1103/PhysRevB.90.104515

Detecting magnetic flux distributions in superconductors with polarized x rays

Claudia Stahl, Patrick Audehm, Joachim Gräfe, Stephen Ruoß, Markus Weigand, Mathias Schmidt, Sebastian Treiber, Michael Bechtel, Eberhard Goering, Gisela Schütz, Joachim Albrecht

DOI 10.1103/PhysRevB.90.104515 · Physical Review B

T1

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Abstract

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). Temperature-dependent XMCD spectroscopy on the magnetic layer has been performed. Exploiting the temperature dependence of the critical current density of the superconductor we find a quantitative correlation between the XMCD signal and the in-plane stray field of the superconductor. Magneto-optical Kerr effect experiments on the sensor layer can simulate the stray field of the superconductor and hence verify the correlation. We show that the XMCD contrast in the sensor layer corresponds to the in-plane magnetic flux distribution of the superconductor and can hence be used to image magnetic structures in superconductors.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	85	Pressure not reported	onset