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Title: High upper critical field in disordered niobium nitride superconductor

Superconducting Niobium Nitride thin films have been deposited on glass, aluminum nitride buffered glass, and oxidized silicon substrates by reactive DC magnetron sputtering at ambient substrate temperatures. The crystal structure of these thin films has been determined to be cubic fcc B1 structure by Glancing Incidence X-Ray Diffraction analysis. The superconducting transition temperatures of the thin films were measured to be greater than 11.6 K with a maximum of 13.4 K. The negative temperature coefficient of resistance observed in these thin films indicates the presence of disorder. Magneto-resistance measurements have been carried out on these thin films patterned into standard four probe geometry upto a maximum magnetic field of 12 T for two films and upto 15 T for the other two films. The dependence of transition temperature on the applied field is analyzed to estimate the upper critical field. The upper critical field for most of the films was estimated to exceed 35 T, while one of the most disordered films had an estimated upper critical field greater than 70 T.
Authors:
; ; ;  [1]
  1. Materials Science Group, IGCAR, Kalpakkam-603102 (India)
Publication Date:
OSTI Identifier:
22308165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BUFFERS; CRITICAL FIELD; FCC LATTICES; GLASS; MAGNETORESISTANCE; MAGNETRONS; NIOBIUM NITRIDES; SPUTTERING; SUBSTRATES; SUPERCONDUCTORS; TEMPERATURE COEFFICIENT; TEMPERATURE RANGE 0000-0013 K; THIN FILMS; TRANSITION TEMPERATURE; X-RAY DIFFRACTION