HYDROTHERMAL GROWTH OF CRYSTALS OF LAALO3
Semiannual technical summary rept. 1 Jul-31 Dec 1965
LITTON SYSTEMS INC MORRIS PLAINS NJ AIRTRON DIV
Pagination or Media Count:
Large single crystals of pale yellow LaAlO3 undoped measuring approximately 12 inch x 12 inch x 14 inch were successfully grown in a 250 ml crucible from a Bi2O3-B2O3 flux. The ratio of B2O3 to Bi2O3 was an important consideration in the composition of the melt compositions consisting of about 19 m B2O3 appeared to produce the best growth. Larger B2O3 ratios produced a glassy melt from which no crystals grew while pure Bi2O3 yielded numerous small crystals no larger than 1 cu. mm. Weight gains of up to 36 have been achieved in the hydrothermal system using flux grown seeds. Hydrothermally reacted and sintered LaAlO3 pellets have been tried as nutrient. Also a hot pressed mixture of the component oxides was tried. Neither approach was completely successful, but each method shows some merit. One large autoclave failed due to cracks in the seal area during the report period. It has been rebored, fitted with a liner and water tested successfully. Optical absorption and fluorescence measurements have been made on flux and hydrothermally grown samples of LaAlO3Cr and on undoped flux grown LaAlO3. The hydrothermally grown samples appear green due to the presence of a transmission band at 5300A.
- Inorganic Chemistry