High-performance amorphous superconducting rhenium films by e-beam evaporation

TL;DR

This paper reports the fabrication of amorphous rhenium superconducting films via electron beam evaporation, achieving record critical temperature and fields, with potential for device applications.

Contribution

It introduces a method to produce amorphous rhenium films with high critical temperature and fields, suitable for superconducting devices.

Findings

Critical temperature exceeds 7 K

Critical current density reaches 5000 A/mm^2

Critical fields above 10 T

Abstract

We present electron beam evaporation of rhenium films on room-temperature substrates. The films are shown to be amorphous and achieve a record-high critical temperature for rhenium - exceeding 7 K at the midpoint of the transition - alongside a high critical current density of 5000 A/mm^2 and critical fields above 10 T. Terahertz spectroscopy reveals a BCS-like character of superconductivity with a zero-temperature energy gap of approximately 2 meV and subgap optical conductivity. Despite being friable, the films are stable and compatible with lift-off processes that opens the capabilities for superconducting device applications.