Superconducting properties of B1 nitrides films obtained by gas-metal reaction for R.F. application

The authors investigated the R.F. behavior of the B1 type superconductors NbN obtained by reacting Reactor Grade Niobium samples in an high purity (10 ppm of total impurities) Nitrogen atmosphere after a baking at high temperature (1800 Celsius) in an UHV Furnace. The obtained samples were characterized by: Determination of the Critical Temperature Tc via a resistive measurement. Crystallographic measurement by X-ray diffraction in order to detect some unwanted phases having lower Tc. Measurements of the R.F. properties Residual Resistance (Rres) and limit R.F. magnetic field Hc of a niobium nitride TM-010 cavity reacted together the samples.