Temperature and magnetic field dependence of NbN film resistivity: 3D weak localization effects

Niobium nitride superconducting films have been deposited by reactive rf magnetron sputtering. Polyepitaxial growth on MgO-coated substrates greatly improves the superconducting properties. The overall film resistivity is found to be widely dependent on the total pressure of the gas mixture. Samples with a negative temperature coefficient of resistance exhibit 3D weak localization effects as characterized by magnetoresistance measurements. The inelastic scattering time is found to vary as T super(-p) with p approximately equals 2, in the temperature range T sub(c)-3T sub(c).