High-rate sputtering of Nb--Al--Ge and Nb--Al superconductors

Conference · Sat Mar 01 04:00:00 EDT 1975 · IEEE Trans. Magn., v. MAG-11, no. 2, pp. 217-220

OSTI ID:4103740

Dahlgren, S D

High quality Nb--Al--Ge and Nb--Al superconductor deposits, up to 1 mm thick, were made at a rate of 1 $mu$m/min using high-rate sputtering techniques. High-rate sputtering eliminates most of the fabrication problems generally encountered with these materials. Reasonable quantities of high-field superconductors can be made at acceptable cost for practical applications by high- rate sputtering. Highly reflective metallic mirror surfaces on these deposits indicate a high quality, even in thicknesses up to 1 mm. The deposits were completely free of voids and they did not seem to be overly brittle either before or after heat treatment. Crystal structures for deposits made at 20$sup 0$C were probably bcc. Heat treatment between 550 and 850$sup 0$C completely transformed the bcc deposits to extremely small (350 A) grains of the A-15 crystal structure. The A-15 phase formed by heat treatment for 1 h to 5 days at 750$sup 0$C was metastable and supersaturated with Al and Ge. Deposition and heat conditions for decomposition of the metastable A-15 phase were identified. The highest critical temperatures (18$sup 0$K) were observed only in those deposits containing undecomposed metastable A-15 phase. To assess practical use of the sputtered superconductors, 1- to 2-m lengths of ribbon and filamentary Nb--Al--Ge superconductor were produced on ribbon and wire substrates. It also was found that an excellent superconductor-stabilizer bond can be formed by high-rate sputter deposition of copper stabilizer onto heat-treated Nb--Al--Ge and Nb--Al superconductors. (auth)

• Research Organization: Battelle Pacific Labs., Richland, WA
• NSA Number: NSA-33-017705
• OSTI ID: 4103740
• Conference Information: Journal Name: IEEE Trans. Magn., v. MAG-11, no. 2, pp. 217-220
• Country of Publication: United States
• Language: English

Related Subjects

*ALUMINIUM ALLOYS-- SPUTTERING
*GERMANIUM ALLOYS-- SPUTTERING
*NIOBIUM BASE ALLOYS-- SPUTTERING
*SUPERCONDUCTORS-- FABRICATION
360101* --Materials--Metals & Alloys--Preparation & Fabrication
CRYSTAL STRUCTURE
HEAT TREATMENTS
N50220* --Metals
Ceramics
& Other Materials--Metals & Alloys--Preparation & Fabrication
N66200 --Physics (Low Temperature)--Superconductivity
PHASE TRANSFORMATIONS
SUPERCONDUCTIVITY
TRANSITION TEMPERATURE