NbN formation on carbon fibers with a duo magnetron sputtering system

Journal Article · Fri Feb 01 04:00:00 EST 1985 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.334688· OSTI ID:6188975

Ohshima, S; Dietrich, M; Linker, G

Superconducting NbN was produced on commercial carbon fibers and sapphire substrates by dc reactive magnetron sputtering. Uniform coating was achieved by spreading 9000 filaments into a strip located between two planar magnetrons facing each other. The conditions for B1 phase formation and homogeneous coating have been studied. Over a rather wide range of total pressures, p/sub Ar/+p/sub N2/, the highest superconducting transition temperature was found for a nitrogen partial pressure p/sub N2/ of about 0.05 Pa. In addition, tensile or compressive strains were produced in the NbN film on the carbon fiber as a function of bias. The NbN grain size was controlled in the range between 10 and 25 nm. Without a bias, the usual (111) preferential orientation of the grains was observed in the NbN film on the carbon fiber. The intensity ratio I/sub 200//I/sub 111/ could be controlled between 0.74 and 0.4. Under an increased bias, the lattice parameter grew from about 0.4385 to about 0.4395 nm. This behavior may be due to a variety of reasons. The superconducting critical currents j/sub c/ in a self-magnetic field are about 10/sup 5/ A/cm/sup 2/ for NbN on carbon fibers (C-NbN) and about 2 x 10/sup 6/ for NbN on sapphire (S-NbN). Various microstructures and, to some extent, also mechanical defects are thought to be responsible for this difference. At 13 T, the corresponding j/sub c/ values are 2 x 10/sup 4/ and 10/sup 5/ A/cm/sup 2/ for NbN films of 1-..mu..m thickness. The extrapolated B/sub c//sub 2/ (4K) values for C-NbN are about 30--35 T, for S-NbN about 25 T.

• Research Organization: Kernforschungszentrum Karlsruhe, Institut fuer Technische Physik, Postfach 3640, D-7500 Karlsruhe, Federal Republic of Germany
• OSTI ID: 6188975
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 57:3; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BACKSCATTERING
CARBON
CHALCOGENIDES
COATINGS
COMPRESSION
CORUNDUM
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
DEPOSITION
ELECTRIC CURRENTS
ELEMENTS
FILMS
GRAIN SIZE
MECHANICAL PROPERTIES
MICROSTRUCTURE
MINERALS
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
PRESSURE EFFECTS
REFRACTORY METAL COMPOUNDS
SAPPHIRE
SCATTERING
SIZE
SPUTTERING
STRAINS
SUPERCONDUCTING FILMS
SURFACE COATING
TENSILE PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE