Electrical Properties and Superconductivity of Rhenium and Molybdenum Films

Abstract

Electrical and superconducting properties of rhenium and molybdenum films prepared by electron beam evaporation have been measured as a function of substrate temperature, film thickness, and substrate material. The films were prepared at residual pressures of 5×10^–8 Torr. In addition, films of each material were prepared by reactive deposition at nitrogen pressures in the 10^–5 Torr range. Rhenium films prepared at low residual pressures exhibited superconductivity with onset temperatures from 2.5–4.9 K depending on thickness and substrate temperature. However, rhenium films prepared by reactive deposition in nitrogen had onset temperatures from 4.6–5.5 K. Transition temperatures from 3.3–3.8 K were observed in molybdenum films at thicknesses greater than 6000 Å when deposited at substrate temperatures of 600 °C. Crystal structure and preferred orientation were determined by x-ray diffraction methods.