ABSTRACT We have established the growth conditions and the starting composition for obtaining large, up to ~40 g, good quality single crystals of Al2 (WO4)3 by the modified Czochralski method. By the same method single crystals of solid solutions of Sc2(WO4)3-Al2(WO4)3 and Lu2(WO4)3-Al2(WO4)3 were grown. Crystals were grown from a WO3 rich composition and the composition range suitable for crystallization is narrow (~ 18% mol to ~22% mol of Al2O3 ). The growth conditions are such that evaporation of WO3 partially compensates a compositional shift in the melt during the growth process and a significant amount of starting material can be crystallized. To our knowledge crystals of this size of Al2(WO4)3 and of its solid-solutions Sc2(WO4)3 and Lu2(WO4)3 are reported for the first time. Al2(WO4)3, (Sc,Al)2(WO4)3 and (Lu,Al)2 (WO4)3 are solid electrolytes with interesting transport, luminescence and thermal properties. These are promising materials for chemical sensor applications and in a single crystal form they are potential laser hosts. Single crystals of this size and quality enabled us to perform further studies of ionic conductivity in this solid electrolyte. Earlier attempts of crystal growth as well as some peculiarities of crystal growth method applied and similar methods are discussed as well.
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