Title :
Measurement of the coherence length of sputtered Nb0.62Ti0.38N thin films
Author :
Yu, Lei ; Newman, Nathan ; Rowell, John M.
Author_Institution :
Dept. of Electr. Eng., Arizona State Univ., Tempe, AZ, USA
fDate :
6/1/2002 12:00:00 AM
Abstract :
Superconducting and normal state properties of the useful film material NbxTi1-xN have been characterized. In particular, the coherence length of reactively sputtered Nb0.62Ti0.38N thin films is determined to be 2.4±0.3 nm. The results are inferred from fitting the de Gennes-Werthamer theory to experimental measurements of the proximity-induced depression of the transition temperature in Nb-Nb0.62Ti0.38N-Nb structures. The coherence length, as defined by this theory, can be used to infer the zero-temperature Ginzburg-Landau coherence length, ξGL (0), of 3.8 nm for the Nb0.62Ti0.38N synthesized in this study. The shorter coherence length and lower resistivity of these films, when compared to NbN, indicates that they are an appealing choice for electrodes in rapid single flux quantum circuits.
Keywords :
coherence length; niobium compounds; proximity effect (superconductivity); sputtered coatings; superconducting logic circuits; superconducting thin films; superconductor-normal-superconductor devices; titanium compounds; type II superconductors; Nb0.62Ti0.38N; coherence length; de Gennes-Werthamer theory; digital logic circuits; energy gap; lattice-matched substrates; normal state properties; pentalayer SNS structures; proximity-induced depression; rapid single flux quantum circuits; sputtered thin films; superconducting properties; temperature-dependent resistivity; transition temperature; zero-temperature Ginzburg-Landau length; Circuit synthesis; Conductivity; Electrodes; Length measurement; Niobium; Sputtering; Superconducting films; Superconducting materials; Superconducting thin films; Superconducting transition temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2002.1020339
