Abstract

We report on the influence of the disorder and stoichiometry in the resulting superconducting critical temperature of gamma-Mo2N thin films. Initially, three films (with T-c values of 7.6 K, 6.8 K and 6 K) were grown at room temperature by reactive sputtering, on Si (1 0 0) using different N-2/(Ar+N-2) mixtures. The influence of the thermal annealing up to 973 K and irradiation damage produced by 1 MeV Zr+(fluence up 2 x 10(14)cm(2)) is analyzed. The T-c of pristine films remains unchanged for increasing irradiation doses up 2 x 10(14)cm(2). The T-c for annealed films decreases close to the value expected for bulk samples (approximate to 5K) for increasing the annealing temperature. Successive irradiations of the annealed films tend to increase their T-c up to its initial values (before annealing). The results indicate that the T-c in nanometric grain size gamma-Mo2N thin films is affected by both nitrogen stoichiometry and disorder at the atomic scale. (C) 2018 Elsevier B.V. All rights reserved.