Vanadium–gallium

Vanadium–gallium (V3Ga) is a superconducting alloy of vanadium and gallium. It is often used for the high field insert coils of superconducting electromagnets.

Vanadium–gallium tape is used in the highest field magnets (magnetic fields of 17.5 T). The structure of the superconducting A15 phase of V3Ga is similar to that of the more common Nb3Sn.[1]

In conditions where the magnetic field is higher than 8 T and the temperature is higher than 4.2 K, Nb3Sn and V3Ga see use.

The main property of V3Ga that makes it so useful is that it can be used in magnetic fields up to about 18 T, while Nb3Sn can only be used in fields up to about 15 T.[2]

The high field characteristics can be improved by doping with high-Z elements such as Nb, Ta, Sn, Pt and Pb.[3]

Physical Properties
Molecular Weight222.55 g/mol
Melting Point1720 °C
Highest magnetic field18 T

[4]

V3Ga has an A15 phase, which makes it extremely brittle. One must be extremely cautious not to over-bend the wire when handling it. [2]

Superconducting properties
  • Critical temperature (Tc): ~14.2 K[5]
  • Upper critical field (Hc2): over 19 T.

Fabrication of superconductive wires or tapes

V3Ga wires can be formed using solid-state precipitation.[6]

  • V3Ga superconducting tape (10 mm × 0.14 mm cross section). A vanadium core is covered with 15 μm V3Ga layer, then 20 μm bronze (stabilizing layer) and 15 μm insulating layer. Critical current 180 A (19.2 T, 4.2 K), critical current density 20 kA/cm2.
  • An example of a wire (V3Ga alloy) used in a superconducting magnet.

History

References
  1. Markiewicz, W.; Mains, E.; Vankeuren, R.; Wilcox, R.; Rosner, C.; Inoue, H.; Hayashi, C.; Tachikawa, K. (1977). "A 17.5 Tesla superconducting concentric Nb3Sn and V3Ga magnet system". IEEE Transactions on Magnetics. 13 (1): 35–37. Bibcode:1977ITM....13...35M. doi:10.1109/TMAG.1977.1059431.
  2. Ekin, Jack W. (1983). "Superconductors". In Reed, Richard P.; Clark, Alan F. (eds.). Materials at Low Temperatures. Russell, OH: American Society for Metals. pp. 465–513. ISBN 978-1-62708-348-5.
  3. Tedrow, P. M.; Meservy, R. (1984), "Improvement in magnetic field properties of vanadium–gallium superconductors by enhancement of spin-orbit scattering", MIT Report, Bibcode:1984mit..reptR....T
  4. "Vanadium Gallide". American Elements.
  5. Decker, D. L. Laquer, H. L. (1969), "Magnetization Studies on Superconducting Vanadium-Gallium", Journal of Applied Physics, 40 (7): 2817–2822, Bibcode:1969JAP....40.2817D, doi:10.1063/1.1658081{{citation}}: CS1 maint: multiple names: authors list (link)
  6. Hong, Minghwei (1980), A15 superconductors through direct "solid-state" precipitation: V3Ga AND Nb3Al


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