The microstructure and electrical transport properties of immiscible copper-niobium alloy thin films
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203 (United States)
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai (India)
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)
Mutually immiscible in the solid state, copper and niobium exhibit a relatively strong clustering (phase separating) tendency in the liquid state and can therefore only be alloyed in a highly metastable form: for example, by vapor quenching. We have deposited metastable Cu-Nb alloy thin films with nominal compositions ranging from 5 to 90 at. % Nb by magnetron cosputtering. The microstructure of these films depends strongly on the composition and ranges from coarse-grained solid solutions for Cu-rich and Nb-rich compositions to phase-separated amorphous mixtures when the two elements are in comparable amounts. The crystalline Cu- or Nb-rich compositions exhibit positive temperature coefficients of resistivity (TCR) with the Cu-90 at. % Nb film exhibiting a superconducting transition with (T{sub C}){sub onset}{approx}4.5 K. The amorphous films show high room temperature resistivity, a negative TCR, and composition dependent superconducting transitions. We investigate the relation between the microstructure, phase stability, and the electrical transport properties.
- OSTI ID:
- 21064535
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 3; Other Information: DOI: 10.1063/1.2836970; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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