Abstract
Growth conditions and crystal morphology of erbium KEr(WO~4~)~2~ (KEW) and samarium KSm(WO~4~)~2~ (KSW) potassium double tungstates have been investigated. Monoclinic single crystals have been grown by TSSG method using K~2~W~2~O~7~ solvent. It was found that the vertical temperature gradient in a range of 0.3 β 0.5 K/mm is optimal for crystal growth. The morphology of grown crystals and their quality strongly depend on the seed orientation. The best results are achieved when the growth takes place on seeds oriented along [010] direction. For KEW, crystal growth is possible by lowering the temperature without pulling. In this case the surfaces of the grown crystals are natural crystallographic planes. KSW crystals grow into the solution down to the depth of 4β6 mm only. Structure analysis of crystals is obtained by XβRay powder diffraction measurements. The diffraction patterns were analyzed by the Rietveld refinement method. XRD measurements shows the symmetry of monoclinic space group C2/c (C^6^~2h~). (Β© 2010 WILEYβVCH Verlag GmbH & Co. KGaA, Weinheim)