Compositional distribution in the cross section of chemical-vapor-deposited Nb/sub 3/Ge tape conductors and its correlation with superconducting properties

Journal Article · Thu Jan 01 04:00:00 EST 1987 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.338821· OSTI ID:6815935

Nakagawa, Y; Yamasaki, H; Kimura, Y

Chemical-vapor-deposited Nb/sub 3/Ge tapes 2.5 mm wide with Nb/sub 3/Ge layer thickness of 5--60 ..mu..m were prepared under various processing conditions. Though the depth profile of the Nb concentration in the Nb/sub 3/Ge tapes determined by x-ray microanalysis was fairly uniform, with a variation less than 4 at. % for many Nb/sub 3/Ge tapes, the distribution of the Nb concentration over the whole cross section of the Nb/sub 3/Ge layer varied considerably, with a variation of 10--18 at. % for various Nb/sub 3/Ge tapes. In this distribution, Nb concentrations at the tape edges were found to be higher than those on its sides for all of the Nb/sub 3/Ge tapes prepared. The origin of this singular distribution of the composition is discussed. The T/sub c/ values for narrower tapes cut out lengthwise from the 2.5-mm-wide tapes were measured resistively. They correlated closely with the compositional distribution in the cross section of the Nb/sub 3/Ge tapes. The T/sub c/ values (midpoints) of Nb/sub 3/Ge tapes incorporating compositions within the Nb concentration range of 70--75 at. % were found to be near or above 20 K.

• Research Organization: Advanced Technology Division, Electrotechnical Laboratory, 1-1-4, Umezono, Sakura-mura, Niihari-gun, Ibaraki 305, Japan
• OSTI ID: 6815935
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 61:1; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMICAL COATING
CHEMICAL COMPOSITION
CHEMICAL VAPOR DEPOSITION
DEPOSITION
FILMS
GERMANIUM COMPOUNDS
NIOBIUM COMPOUNDS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
SUPERCONDUCTING FILMS
SURFACE COATING
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE