STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF NB-TI ALLOY THIN-FILMS

Structural instability in Ti-rich compositions of Nb-Ti alloy systems, which leads to various anomalies in the normal and superconducting st ate properties, has been extensively studied in bulk samples in the pa st. It would be interesting to study the instability through the super conducting tunnelling technique which is more amenable in thin-film sa mples. As a first step we report in this paper the formation of thin f ilms of several compositions in the Ti-rich region of such alloy syste ms by RF magnetron sputtering and investigation of their electrical pr operties. Compositional analysis of two representative films was carri ed out by the RES technique and the compositions agreed to within 2% o f the targeted values. Anomalous variations in the electrical charcter istics of the bulk, which can be ascribed to structural instability re lated to the formation of athermal omega-phase, are also observed in t hin films. (C) 1996 Elsevier Science Limited