New phase formation and superconductivity in reactively diffused Nb/sub 3/Sn multilayer films
Thin films of A15 Nb/sub 3/Sn have been prepared by reactive diffusion of sputter-deposited Nb/Sn multilayers. The layer thicknesses were arranged in such a way as to produce Nb/sub 3/Sn and desired off-stoichiometry samples. The reaction was studied by means of in situ temperature-dependent X-ray analysis in the range 50/sup 0/C-950/sup 0/C. It was observed that, prior to the formation of the A15 phase, a very rapid reaction takes place between the Nb sublayers and molten Sn. In this reaction a new phase was observed which could be interpreted as a hexagonal Laves phase NbSn/sub 2/. This phase transforms into orthorhombic NbSn/sub 2/ which then reacts with the remaining Nb to form A15 Nb/sub 3/Sn. The fact that the reaction occurs at the Nb/liquid Sn interface with the formation of the most Sn-rich phase indicates that the reaction takes place by diffusion of Nb into liquid Sn. The highest superconducting transition temperature was found to be 17.45/sup 0/K. The values of the A15 cell parameters indicated that the diffusion reaction of both onand off - stoichiometry Nb/sub 3/Sn multilayers is driven towards the Sn-rich side of Nb/sub 3/Sn, with a maximum composition range of 24-28 at% Sn.
- Research Organization:
- ATandT Bell Laboratories, Murray Hill, NJ
- OSTI ID:
- 6486070
- Report Number(s):
- CONF-840937-
- Journal Information:
- IEEE Trans. Magn.; (United States), Journal Name: IEEE Trans. Magn.; (United States) Vol. MAG-21:2; ISSN IEMGA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102 -- Metals & Alloys-- Structure & Phase Studies
420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
CRYSTAL-PHASE TRANSFORMATIONS
DIFFUSION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SPUTTERING
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
THIN FILMS
TIN ALLOYS
TRANSITION TEMPERATURE