CZOCHRALSKI GROWTH OF LaAlO3
Final technical rept. for Jan-May 1965
UNION CARBIDE CORP INDIANAPOLIS IN LINDE DIV
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The program explores the possibility of growing high optical quality LaAlO3 by the Czochralski method. The techniques developed for ruby growth were found to be directly translatable to LaAlO3 with no apparent limitations imposed by the use of a crucible. Undoped and doped Cr3, Eu3 crystals of various orientations were grown. Two major defects were encountered color centers and twinning. Color centers were eliminated by using high purity starting materials in combination with selected growth and post-growth treatment. Two mechanisms for forming color centers are proposed and their relation to LaAlO3 defect chemistry is discussed. The dominant twin planes have been identified to be those of the 100 system. Their relation to the crystal strucutre of LaAlO3 has been elucidated. Isolated attempts were made to grow BiAlO3 and PrAlO3 to determine if twinning might be a problem in these potential host compositions other growth problems were encountered indicating that an answer could be obtained only by an extensive effort beyond the bounds of the present program.