EFFECTS OF SC2O3 ADDITION ON FLOATING ZONE GROWTH OF RUTILE SINGLE-CRYSTALS

Rutile single crystals doped with Sc2O3 were grown by the floating zone (FZ) method. The as-grown crystals were yellowish and transparent after the growth run, whereas an as-grown pure rutile crystal is dark-blue and not transparent even if the crystal growth is done under an oxygen atmosphere. The Sc3+ ions could substitute Ti4+ sites in the rutile structure to form oxygen vacancies, via which oxide ions could easily diffuse as well in Y2O3-doped ZrO2, and consequently transparent as-grown crystals were obtained. The formation of low-angle grain boundaries was appreciably suppressed, but not completely, with the addition Of only SC2O3. Simultaneous addition of Sc2O3 and ZrO2 was effective to obtain transparent and grain-boundary-free rutile single crystals by the floating zone method.