Crystallization behavior of a barium titanate tellurite glass doped with Eu3+ and Er3+

The main objective of this work has been to investigate the crystallization behavior of the glass composition 70TeO2–15BaO–15TiO2 doped with Eu3+ and Er3+ in order to check the possibility of obtaining transparent glass–ceramics containing rare earth-doped BaTiO3 nanocrystals. Glass samples with the ternary composition 70TeO2–15BaO–15TiO2 were synthesized by the melt-quenching method and doped with 0.1% of Eu3+ and Er3+. Thermal properties were investigated by DTA and heat-treatments were applied between Tg and Tx to induce the controlled crystallization of these glasses. One-step and two-step heat treatments were tested and the final glass–ceramics characterized by X-ray diffraction and UV–Vis absorption. It has been shown that transparent glass–ceramics can be obtained after heat-treatment but barium titanate BaTiO3 is hardly precipitated without coprecipitation of another crystalline phase identified as an isostructure of lanthanum tellurate. In addition, the crystalline volume fraction is relatively small in these transparent samples. Finally, Gold doping has been shown to be very effective to promote a volume nucleation and preferential crystallization of BaTiO3 over the other crystalline phases.

► Stable Eu3+ and Er3+ barium titanate tellurite glasses were prepared.
► Crystallization studies shown that transparent glass–ceramics can be obtained.
► Barium titanate BaTiO3 is precipitated together with another crystalline phase identified as an isostructure of La10Te6O27.3.
► Gold doping is efficient to promote volume nucleation and preferential precipitation of BaTiO3.