Ion channeling in NbC/sub 1-c/: Determination of local atomic displacements around carbon vacancies
The results of channeling experiments on NbC/sub 1-c/ single crystals as a function of the vacancy concentration (0.02< or =c< or =0.18) are presented. Angular yield curves using Rutherford backscattering and nuclear reactions for the Nb and the C yields, respectively, were measured at temperatures of T = 5, 78, and 295 K. Statical lattice calculations were used to construct a defect model with displacements of the first and second Nb neighbors of a C vacancy. Monte Carlo calculations have been performed with this defect model to analyze the experimental channeling data. Displacements of the first Nb neighbors of u/sub 1/ = 0.12 +- 0.025 A and of the second Nb neighbors of u/sub 2/< or =0.03 +- 0.01 A around isolated C vacancies have been determined. At high vacancy concentrations (c = 0.18) the displacements of the first neighbors decreased to values of u/sub 1/ = 0.09 +- 0.007 A and of the second neighbors to values of u/sub 2/< or =0.02 +- 0.007 A. The static displacements determined with the channeling method were in good agreement with the results of x-ray diffraction experiments.
- Research Organization:
- Institut fuer Nukleare Festkoerperphysik, Kernforschungszentrum Karlsruhe GmbH, P.O. Box 3640, D-7500 Karlsruhe, Federal Republic of Germany
- OSTI ID:
- 5223019
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 28:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NIOBIUM CARBIDES
ION CHANNELING
VACANCIES
ANGULAR DISTRIBUTION
HELIUM IONS
LATTICE PARAMETERS
LOW TEMPERATURE
MEDIUM TEMPERATURE
MEV RANGE 01-10
MONOCRYSTALS
NEUTRON REACTIONS
QUANTITY RATIO
RUTHERFORD SCATTERING
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
BARYON REACTIONS
CARBIDES
CARBON COMPOUNDS
CHANNELING
CHARGED PARTICLES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
DISTRIBUTION
ELASTIC SCATTERING
ENERGY RANGE
HADRON REACTIONS
IONS
MEV RANGE
NIOBIUM COMPOUNDS
NUCLEAR REACTIONS
NUCLEON REACTIONS
POINT DEFECTS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies