NbN superconducting thin films grown by pulsed laser ablation

Abstract

NbN superconducting thin films have been grown by using pulsed laser ablation in a N 2 pure atmosphere. The X-ray spectra indicate that highly oriented superconducting NbN films having a FWHM of the 002 reflection narrower than 0.5°, has been obtained. Critical zero resistance temperature T c higher than 16.3 K and resistivity ratio ≈ 1.3 were measured as well as critical field of 12 T at LHe temperature on the high quality films. Transport critical current density J c, measured on a patterned film with a 50 μV cm criteria, gave an extrapolated value of J c0 higher than 1 × 10 7 A/cm 2 computed by using a Kim Andersen model. Preliminary photoemission spectroscopy measurements in the presence of N 2 background gas indicate some reactivity in the plume region.