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arXiv · 2404.17320

Percolative supercurrent in superconductor-ferromagnetic insulator bilayers

A. Maiani·A. C. C. Drachmann·L. Galletti·C. Schrade·Y. Liu·R. Seoane Souto·S. Vaitiekėnas
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Abstract

We report tunneling spectroscopy and transport measurements in superconducting Al and ferromagnetic-insulator EuS bilayers. The samples display remanent spin-splitting, roughly half the superconducting gap, and supercurrent transport above the average paramagnetic limit. We interpret this behavior as arising from the interplay between two characteristic length scales: the superconducting coherence length, $\xi$, and the magnetic domain size, $d$. By comparing experimental results to a theoretical model, we find $\xi/d \approx 10$. In this regime, spin-averaging across the micromagnetic configuration can locally suppress superconductivity, resulting in percolative supercurrent flow.

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A. Maiani, A. C. C. Drachmann, L. Galletti, C. Schrade, Y. Liu, R. Seoane Souto, S. Vaitiekėnas. 2024-04-26. Percolative supercurrent in superconductor-ferromagnetic insulator bilayers. https://doi.org/10.1103/physrevb.111.174509

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