Phase Equilibria in LiYF4–LiLuF4 System and Heat Conductivity of LiY1–xLuxF4 Single Crystals

Abstract

Single crystals of LiY_1–xLu_xF₄ (x = 0, 0.25, 0.5, 0.65, 0.9) solid solution were grown by Bridgman–Stockbarger technique. Melting points determined by DSC monotonically varied with composition from 831 to 841 K when x increased. Interval between liquidus and solidus curves is not larger 1°C. This feature extremely favors to the growth of homogeneous single crystals from melt. Heat conductivity (κ) of solid solution is lower than that of LiYF₄ and LiLuF₄ components. In the region 0.25 ≤ x ≤ 0.65 at 300 K, κ = 4 ± 0.1 W/(m K).