NbN films on vicinal to the X-cut of LiNbO3 surfaces

Abstract

We report a study of epitaxial superconductive NbN films on vicinal to the X-cut of single crystal LiNbO3 substrates grown using reactive magnetron sputtering of Nb target in Ar-N2 atmosphere. It is found that the NbN films reveal sharp superconductive transition at TC = 15.2 K and anisotropy of critical current. Critical current measured along the Z direction exceeds JC along the Y direction regardless of the orientation of step edges of the vicinal surfaces. The anisotropy effect is attributed to NbN film uniaxial stress due to the lattice mismatch of NbN (0 0 1) layer along the Z direction of LiNbO3.