ИСТИНА

According to the known of PbF2?REF3 (RE= rare-earth elements) phase diagrams wide regions of crystallization of the fluorite-type cubic phase are observed, but at temperatures lower 650°? the data on synthesis conditions and functional parameters of cubic PbF2 based solid solutions are not presented. The homogeneity limits of the solid solutions in the PbF2?REF3 systems at 650°? were determined as 20-25 mol % of RE fluoride. The solid solutions in the PbF2?REF3 (RE=Eu, Er) systems were synthesized two techniques: the solid-phase method; the coprecipitation from aqueous solutions in the composition range from 0 to 100 mol% of REF3. The structures of solid solutions have been investigated. It was found that an increase of RE concentration in the initial solution during the coprecipitation promoted the crystallization of the high-temperature cubic phase of solid solutions based. It was determined that >7 mol% europium in the solution was enough to obtain the high-temperature cubic phase. The photoluminescence spectra of solid solutions obtained have been studied. The luminescent centers of Eu3 in solid solutions obtained by the solid-state synthesis had a greater symmetry than those obtained by the coprecipitation from aqueous solutions. This research was financially supported by the grant 17.1.18.0026.01 (10.4702.2017/BC).