A new approach to the growth of langasite crystals

Abstract

Preparation of the initial charge, crystal growth process and crystal quality assessment of langasite are described. The initial charge preparation is based on an original method named self-distribution high-temperature synthesis (SHS), which is applied for the first time to mixtures of lanthanum and silicon oxides and metallic gallium. Influence of the main growth conditions on the crystal quality is discussed. The advantages of using iridium as crucible material are shown. A value of the crystal size as big as 70 mm of diameter was reached. Crystal quality is evaluated to be high enough to produce monolithic 80 MHz filters.