Composition versus a/sub 0/ and T/sub c/ relations in superconducting Nb/sub 3/Ge thin films

Journal Article · Fri Oct 01 04:00:00 EDT 1976 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.322391· OSTI ID:7176518

Rogowski, D A; Roy, R

A large series of well-crystallized Nb/sub 3/Ge thin films have been prepared by carefully controlled rf sputtering. The compositions expressed as Nb/Ge ratios for these essentially single-phase Nb/sub 3/Ge thin films were determined by electron microprobe (EMP) analysis, ion scattering spectrometry, and wet chemistry (WC). Based on lattice-parameter considerations, this series of films spanned the entire homogeneity range of Nb/sub 3/Ge phases, from the metastable Ge-rich end (a/sub 0/<5.167 A) to the metastable Nb-rich end (a/sub 0/>5.176 A). The data from the different analytical methods and annealing experiments suggest that typical films are Ge enriched at the substrate interface and germanium and/or oxygen enriched for almost 600 A from the exposed surface. Intercorrelations of increased reliability have now been established between T/sub c/, the Nb/Ge ratio, and a/sub 0/. An extrapolation of the EMP Nb/Ge ratio versus a/sub 0/ and T/sub c/ data predict an a/sub 0/ of 5.127 A and a T/sub c/ of 23.4/sup 0/K for a phase of Nb/sub 3/Ge stoichiometry. The correlation between the EMP Nb/Ge ratio and a/sub 0/ obtained from a single-phase bulk Nb/sub 3/Ge sample was found to be in excellent agreement with the data obtained from the present study's rf-sputtered Nb/sub 3/Ge thin films. (AIP)

• Research Organization: Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
• OSTI ID: 7176518
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 47:10; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals &amp; Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
&amp; Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ANNEALING
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROPROBE ANALYSIS
FILMS
GERMANIUM ALLOYS
HEAT TREATMENTS
LATTICE PARAMETERS
MICROANALYSIS
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
PHASE STUDIES
PHYSICAL PROPERTIES
RELIABILITY
SPUTTERING
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE