The luminescence microspectroscopy of Pr3+-doped LiBaAlF 6 and Ba3Al2F12 crystals

Abstract

The combined luminescence and Raman-scattering microspectroscopy technique allows separate spectroscopic studies on several crystal phases in mixed compounds. A mixed sample of LiBaAlF6 and Ba3Al 2F12 doped with Pr was studied. The Pr3+ concentration was found to be much higher in the Ba3Al 2F12 phase. Several non-equivalent Pr3+ centers are present in both compounds, however, only in Ba3Al 2F12 there are several non-equivalent crystallographic positions of Ba. In LiBaAlF6 non-equivalent Pr3+ centers appear because of complicated scheme for charge compensation of ( PrBa3+)+. Possible reasons of Ba3Al2F 12 formation in the process of Pr3+:LiBaAlF6 growth are discussed. An excess of LiF in melt is assumed to produce ( LiBa+)- antisite defects as a charge compensation for ( PrBa3+)+ substitution. © 2013 Elsevier Ltd. All rights reserved.