Superconducting properties of reactively sputtered NbCN thin films

Abstract

Niobium Carbonitride thin films have been prepared by rf reactive sputtering of niobium in ar argon, reactive-gas (RG) atmosphere where the RG is a mixture of cyanogen and nitrogen. Film composition ranged from Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</inf> C <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.03\leq \times \leq0.5</tex> ) as determined by Auger analysis, the carbon content roughly tracking the cyanogen partial pressure. Composition and substrate temperature were systematically varied and the resultant films studied by measurements of x-ray structure, resistivity, superconducting transition temperature T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> , and critical magnetic fields. We have found systematic preferential orientation of the crystallites in these films depending upon substrate temperature ana RG to argon ratio. Increasing either quantity causes the crystallites to reorient from the