Nucleation and crystallization behavior of RE - doped tellurite glasses

Abstract

Abstract. The microstructure and crystallization of the glasses with composition (100-xy)TeO 2 -xPbO•P 2 O 5 -yPbF 2 :zMF 3 (M= Er, Eu, Nd; x=42.5-30, y=5-30, z=0.5-3.0) were investigated by transmission electron microscopy (TEM) and luminescence methods. It was found that the doping with the rare-earth (III) fluorides promoted nucleation in the bulk glasses. The sizes of generated particles are about 2-5 nanometers and their shapes are close to spherical. The growth rate of crystallites depended on the lead fluoride content and glass forming rate. The heat treatment of the samples promotes the glass ceramic formation, where the crystalline phase is Pb 2 P 2 O 7 . IntroductionTellurium dioxide based glasses are of increasing interest due to a possibility of their application as components of the optical data storage devices and telecommunication systems [1,2]. It is possible to use these glasses in production of lasers because of the high solubility of rare-earth ions and relatively low phonon energy among oxide glass-formers [3]. Doped glass ceramics are the most perspective materials for these applications. Rare-earth fluorides often act as nucleating centers [4].Preparation of oxyfluoride glasses in the ternary system TeO 2 -PbF 2 -CdF 2 was reported previously [5]. Recently the Pb(PO 3 ) 2 -TeO 2 glass system was studied in the whole range of glass composition [6]. Furthermore, a glass formation of the TeO 2 -PbO•P 2 O 5 -PbF 3 : MF 3 system was investigated [7]. We analyzed in [7] the thermal properties and the ionic mobility in the system TeO 2 -PbO•P 2 O 5 -PbF 3 : MF 3 (M = Er, Eu, Nd) by the DTA and NMR methods. This paper is a continuation of the work mentioned above. Our purpose was to consider an effect of the rare-earth (III) fluorides on crystallization of the TeO 2 -PbO•P 2 O 5 -PbF 3 : MF 3 system.