The effect of ion damage and annealing on superconducting transition metal-nitride compounds

Technical Report · Sun Mar 01 04:00:00 EST 1987

OSTI ID:6973087

Ellis, J T

Thin films of the B1 phase superconducting compounds vanadium nitride and titanium nitride were formed by heating evaporated pure metal films in high purity nitrogen gas. Resistivity at room and low temperature, superconducting transition temperature T/sub C/, and upper critical field of these films were found to be similar to those in bulk samples. The films were then irradiated with nitrogen ions and the effect of lattice damage determined. The dependence on ion fluence of the residual resistivity and the transition temperature obeyed saturating exponential functions that could be derived from a simple defect production and annealing model. The renormalized electronic density of states N*(O) was calculated as a function of ion fluence, while the band density of states Nb(O) was calculated using the electron lifetime model. The electron-phonon coupling constant was determined from these densities of states and from the McMillan equation for T/sub C/. Results do not agree and spin fluctuations cannot be used to explain the discrepancy. It is argued that some mechanism, other than lifetime reduction of the band density of states, is responsible for the observed effects. This is in contrast to the high temperature A15 superconductors in which the electron lifetime model yields large reductions in Nb(O). It is thought that any other mechanism present in these materials would be overshadowed by this large reduction. Subsequent annealing studies indicate that the radiation damage effects are reversible. Annealing in vacuum at high temperatures results in loss of nitrogen and thus degradation of the properties of the material. It is argued that the bonding in TiN is almost three times stronger than in VN.

• Research Organization: Tennessee Univ., Knoxville (USA); Oak Ridge Associated Universities, Inc., TN (USA)
• DOE Contract Number: AC05-76OR00033
• OSTI ID: 6973087
• Report Number(s): DOE/OR/00033-T280; ON: DE87005988
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360206* -- Ceramics
Cermets
& Refractories-- Radiation Effects
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
BEAMS
CHARGED PARTICLES
CRITICAL FIELD
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON-PHONON COUPLING
ELECTRONIC SPECIFIC HEAT
FILMS
GINZBURG-LANDAU THEORY
HEAT TREATMENTS
ION BEAMS
IONS
MAGNETIC FIELDS
NITRIDES
NITROGEN COMPOUNDS
NITROGEN IONS
PENETRATION DEPTH
PHYSICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
PNICTIDES
RADIATION EFFECTS
SPECIFIC HEAT
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
THIN FILMS
TITANIUM COMPOUNDS
TITANIUM NITRIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VANADIUM COMPOUNDS
VANADIUM NITRIDES