Thickness dependence of the superconducting properties of γ- Mo 2 N thin films on Si (001) grown by DC sputtering at room temperature

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

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 γ-Mo2N thin films grown by reactive DC sputtering on AlN buffered Si (001) substrates. The films were grown at room temperature. The shows a microstructure of the films, which was studied by X‐ray diffraction and transmission electron microscopy, shows a single‐phase with nanometric grains textured along the (200) direction. The films exhibit highly thickness in areas larger than 20 x 20 μm². 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 λ(0) ≈ (800 ± 50) nm and a thermodynamic critical field Hc (0) = (500 ± 80 Oe).