Interplay Between Ferromagnetism and Superconductivity in van der Waals Devices

Two-dimensional van der Waals materials have unlocked the ability to stack electronically dissimilar materials into heterostructures that are highly tunable using proximity effects, gate modulation, and varying layer numbers. Interest in superconducting proximity effects, such as Andreev reflection in superconductor-normal (S-N) junctions and Josephson junctions, have thus provoked numerous studies in these systems, but the combination of spin-singlet superconductors (S) and spin-polarized ferromagnets (F) into S-F interfaces has been largely unexplored in van der Waals materials. Proper understanding and control of these interfaces could lead to advances in spintronics and novel realizations of unconventional superconductivity. We used superconducting and ferromagnetic van der Waals materials to study the electrical properties of S-F interfaces through transport measurements as we vary both the temperature and the magnetic field.