X-ray studies of pure and doped vanadium sesquioxide

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6013486

Chen, S

The crystal structure of V/sub 2/O/sub 3/ was studied first with substitution by Cr/sub 2/O/sub 3/ from 0 to 5% Cr, then as a function of temperature, with 0.325% and 0.350% Cr content, from 23/sup 0/ to 550/sup 0/C; finally, the distribution of valence electron density in metallic V/sub 2/O/sub 3/ and insulating 1.0% Cr-V/sub 2/O/sub 3/ was mapped, using x-ray diffraction data from single crystals. Doping V/sub 2/O/sub 3/ with up to 1.25% Cr produces changes in structure consistent with a slight weakening of the bonding metal-metal interactions in the basal plane, leading to an increase in the metal-metal distances coupled with changes which maintain constant metal-oxygen distances. A discontinuity appears at about 1.25% Cr as the first-order transition from metal to insulating behavior occurs with increasing Cr content. No change in crystal symmetry accompanies this transformation. It appears that the metal-metal interactions are retained even in the insulating phase of Cr-doped V/sub 2/O/sub 3/. The distribution of valence electron density in metallic V/sub 2/O/sub 3/ and insulating 1.0% Cr-V/sub 2/O/sub 3/ are similar. Both show significant bonding interaction between near-neighboring metal atoms.

• OSTI ID: 6013486
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
DOPED MATERIALS
ELECTRON DENSITY
MATERIALS
OXIDES
OXYGEN COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
VANADIUM OXIDES
X-RAY DIFFRACTION