Phase Equilibria and Crystal Growth for LiREF4 Scheelite Crystals

TL;DR

This paper investigates the phase equilibria and crystal growth behaviors of LiREF4 scheelite crystals, revealing their melting characteristics and how mixed RE elements influence their melting and solidification processes.

Contribution

It provides new insights into the melting behavior of LiREF4 mixed crystals with multiple rare earth elements, especially Gd and Lu, which was previously not well understood.

Findings

LiREF4 melts congruently only for certain RE elements like Er, Tm, Yb, Lu, Y.

For Eu, Gd, Tb, Dy, Ho, LiREF4 undergoes peritectic melting.

Mixed Gd-Lu crystals melt peritectically or directly depending on composition.

Abstract

The scheelite type laser crystals LiREF4 melt congruently only for RE being one of the elements Er, Tm, Yb, Lu, or possibly Y, respectively. For RE = Eu, Gd, Tb, Dy, or Ho the corresponding scheelites undergo a peritectic melting under the formation of the corresponding rare earth fluoride. The melting behavior of LiREF4 mixed crystals with two or more RE is not yet known well. If RE is a mixture of Gd and Lu, Gd rich solid solutions melt peritectically under formation of (Gd,Lu)F3 and Lu rich solid solutions melt directly without formation of other solid phases.