Growth of binary lithium-rare earth metal fluoride monocrystals and their properties

To improve the data on formation of compounds of LiLnF4, a study has been made of the central parts of phase diagrams of some systems LnF3-LiF by the differential-thermal analysis. A complete study of the system ErF3-LiF has been conducted. It is found that upon relpacement of one rare-earth element (Ln) by another, a lighter one (in system containing fluorides of Eu, Tb, Dy and Er), the peritectic point shifts to higher contents of LiF. The maximum amount of LiF (62 (62 mol.%) is contained in the peritectic point of the system EuF3-LiF. The study of the LuF3-LIF indicates a real possibility of the congruent melting of compounds LiLuF4. The method of growth of single crystals from a solution in the melt can be considered as most convenient to obtain single crystals of compounds with incongruent melting points. By the Chokhralsky method optical single crystals of LiDyF4, LiHoF4, LiFrF4, LiTmF4, LiYbF4, and LiLuF4 in the fluorizating atmosphere have been prepared. Compounds LiEuF4, LiGdF4, and LiTbF4 have been prepared as polycrystals. A number of activated crystals LiYF4-Ln3+ are also grown