Properties of single crystal beta''-aluminas

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6004055

Bates, J. B.; Brown, G. M.; Kaneda, T.; Brundage, W. E.; Wang, J. C.; Engstrom, H.

Large single crystals of sodium beta''-alumina were grown by slow evaporation of Na/sub 2/O at 1690/sup 0/C from a mixture of Na/sub 2/CO/sub 3/, MgO, and Al/sub 2/O/sub 3/. Polarized Raman measurements were made on the Na ..beta..'' single crystals and on single crystals of Li, K, Rb, and Ag ..beta..'' prepared by ion exchange of Na ..beta..''. The low frequency Raman spectra of Na, K, Rb, and Ag ..beta..'' contained four or more bands due to vibrations of the mobile cations. These results were analyzed by assuming the spectra to be due to the normal modes of a defect cluster consisting of a cation vacancy surrounded by three cations. From model calculations, the Raman band of Na ..beta..'' at 33 cm/sup -1/ is assigned to the attempt mode for diffusion of Na/sup +/ ions. The structure of a Ag ..beta..'' single crystal was investigated by neutron diffraction, and 20% of the Ag /sup +/ ion sites were found to be vacant.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6004055
• Report Number(s): CONF-790538--9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALI METAL COMPOUNDS
ALKALI METALS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
IONIC CONDUCTIVITY
LITHIUM
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POINT DEFECTS
POTASSIUM
RAMAN SPECTRA
RUBIDIUM
SILVER
SODIUM COMPOUNDS
SODIUM OXIDES
SPECTRA
TRANSITION ELEMENTS
VACANCIES