Affiliation:
1. Shubnikov Institute of Crystallography of Kurchatov Complex of Crystallography and Photonics of NRC “Kurchatov Institute”
2. A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences
Abstract
Based on thermodynamic-topological analysis, the concentration regions for obtaining homogeneous crystals in the MF2–M'F2–RF3 systems (M≠M' = Ca, Sr, Cd, Ba and Pb, R = rare earth elements, REEs) were determined. Fluorite solid solution crystals in the PbF2–CdF2–RF3 systems (R = Tb, Ho, Er, Tm, Yb and Lu) were grown by the vertical directional crystallization technique. Their phase composition and distribution of components along the length of the crystalline boule were studied. Crystals of congruently melting solid solutions (Pb0.67Cd0.33)1–xRxF2+x (R = Tb, Ho, Er, Tm, Yb, Lu) were grown for the first time. In crystals with R = Ho, Er, Tm and Yb traces of low-temperature ordering of the solid solution were found – phase isostructural to the Pb2YF7 compound (sp. gr. I4/m), in which the Y positions are occupied by the corresponding R cations, and the Pb positions can be partially replaced Cd cations. Crystals with R = Tb and Lu have a high degree of homogeneity and are suitable for optical research.
Publisher
The Russian Academy of Sciences