CZOCHRALSKI GROWTH OF SRLAALO4 AND SRLAGAO4 SINGLE-CRYSTALS AND ITS IMPLICATIONS FOR THE CRYSTAL MORPHOLOGY

Single crystals of SrLaAlO4 (SLA) and SrLaGaO4 (SLG) have been grown f rom nonstoichiometric melts by the Czochralski method making use of di fferent seed orientations, [100] (SLA, SLG), [110] (SLA) and [001] (SL G). The anisotropic properties of the crystal structure are reflected in the growth morphology of the crystals. In the case of (SLA) {101} f acets appear at the crystal/melt interface and in that of [100] SLG {1 01} and {103} facets occur, while for [001] SLG {001} and {103} facets are present. SLA crystals are very similar to the theoretical growth forms computed according to the Hartman-Perdok theory for models with an effective charge on oxygen, q(0) -2\e\. However the habit of SLG cr ystals corresponds better to the theoretical growth forms based on an effective charge q(0) = -1.5\e\ due to the presence of oxygen vacancie s.