Spectroscopy and Distribution of Ce3+ Ions Content in CaF2–SrF2–BaF2 Crystals

Abstract

The single crystals of CaF₂–SrF₂–BaF₂–CeF₃ solid solutions with different concentrations of cerium were grown by Bridgman technique in vacuum with CF₄ fluorinating atmosphere. The recorded X‑ray powder diffraction (XRD) patterns correspond to single-phase samples with a fluorite crystal structure. The composition of the samples was confirmed by energy dispersive analysis (EDX). Five excitation bands around 210, 245, 256, 298 and 314 nm were observed according to spectral-luminescent data and had corresponding luminescence and absorption bands. Luminescence bands with maxima at 313 and 333 nm are related to impurity center with the symmetry C_4v, and those which around 340 and 370 nm are typical for the Ce³⁺ center of trigonal symmetry C_3v. From the recorded absorption spectra it follows that cerium ions concentration decreases along the crystals with maximum value at the beginning of crystallization part.