Thickness dependence of the superconductivitng properties of gamma- Mo2N thin films on Si (001) grown by DC sputtering at room temperature

N. HABERKORN; S. BENGIO; S. SUAREZ; P. D. PEREZ; H. TROIANI; P. GRANELL; F. GOLMAR; M. SIRENA,; J. GUIMPEL

MATERIALS CHEMISTRY AND PHYSICS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2018 vol. 204 p. 48 - 57

0254-0584

We study the crystalline structure and superconducting properties of gamma-Mo2N thin films grown by DC sputtering on AlN buffered Si (001) substrates. The films were grown at room temperature. The microstructure of the films, which wasstudied by X‐ray diffraction and transmission electron microscopy, shows a single‐phase with nanometric grains textured along the 00l direction. The films exhibit highly uniform thickness in areas larger than 20 x 20 um2. The superconducting critical temperature Tc is suppressed from 6.6 K to ≈ 3.0 K when the thickness decreases from 40 nm to 5 nm. The residual-resistivity ratio is slightly smaller than 1 for all the films, which indicates very short electronic mean free path. The films are in the superconducting dirty limit with upper critical field Hc2 (0) ≈ 12 T for films with thickness of 40 nm, and 9 T for films with thickness of 10 nm. In addition, from the critical current densities Jc in the vortex-free state, we estimate a penetration depth lambda(0) ≈ (800 +/-50) nm and a thermodynamic critical field Hc (0) = (500 +/- 80 Oe).