The effect of ion damage and annealing on superconducting transition metal-nitride compounds
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
- Resource Relation:
- Other Information: Thesis. Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
TITANIUM NITRIDES
PHYSICAL RADIATION EFFECTS
VANADIUM NITRIDES
ANNEALING
CRITICAL FIELD
ELECTRON-PHONON COUPLING
ELECTRONIC SPECIFIC HEAT
GINZBURG-LANDAU THEORY
ION BEAMS
NITROGEN IONS
PENETRATION DEPTH
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
THIN FILMS
TRANSITION TEMPERATURE
BEAMS
CHARGED PARTICLES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
HEAT TREATMENTS
IONS
MAGNETIC FIELDS
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
RADIATION EFFECTS
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
360206* - Ceramics
Cermets
& Refractories- Radiation Effects
656100 - Condensed Matter Physics- Superconductivity