Growth of Fluorite Solid Solution Crystals in the Ternary SrF2–BaF2–LaF3 System and Investigation of Their Properties

A series of three-component isostructural fluorite crystals (Sr1–xBax)0.7La0.3F2.3 (sp. gr. Fm3̄m , 0 ≤ x ≤ 1), the compositions of which belong to the Sr0.7La0.3F2.3–Ba0.7La0.3F2.3 polythermal section in the SrF2–BaF2–LaF3 system, has been grown for the first time by vertical directional crystallization. Optical, mechanical, and electrical properties of three-component (Sr1–xBax)0.7La0.3F2.3 and two-component M0.7La0.3F2.3 (M = Sr or Ba) crystals have been investigated and subjected to comparative analysis. It is shown that all three-component crystals (Sr1–xBax)0.7La0.3F2.3 are promising optical design materials.