Enhancing The Critical Magnetic Field of Thin Aluminum Films With Platinum

The emergence of zero-energy states called Majorana zero modes (MZM) is associated with the opening of the superconducting gap in a topological superconductor. Engineering topological superconductivity in superconductor-semiconductor heterostructures typically requires substantial Zeeman energy provided by coupling electron spins to the magnetic field. However, high magnetic fields are detrimental to the superconducting gap. We study the critical field of ultra thin aluminum films by adding a sub-monolayer of platinum. We present data on Josephson junctions fabricated with Al/Pt superconducting films and study the junction critical magnetic fields. We also study this material’s applications for Josephson junction arrays.