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, ξ, and the magnetic domain size, d. By comparing experimental results to a theoretical model, we find ξ/d≈10. In this regime, spin-averaging across the micromagnetic configuration can locally suppress superconductivity, resulting in percolative supercurrent flow.
@article{arxiv.2404.17320,
title = {Percolative supercurrent in superconductor-ferromagnetic insulator bilayers},
author = {A. Maiani and A. C. C. Drachmann and L. Galletti and C. Schrade and Y. Liu and R. Seoane Souto and S. Vaitiekėnas},
journal= {arXiv preprint arXiv:2404.17320},
year = {2025}
}