Neutron diffraction investigation of strontium tellurite glass, anti-glass and crystalline phases

Abstract

ABSTRACT Neutron diffraction studies were performed on xSrO-(100-x)TeO2 (x = 5, 7.5 and 10 mol%) glass, anti-glass and crystalline samples. For the structural modeling, Fourier transformation, Reverse Monte Carlo (RMC) simulations and Rietveld refinement were used. The pair distribution functions show the nearest neighbor peaks of Sr—O, Te—O and O—O correlations at 2.64, 1.95 and 2.70 Å, respectively. RMC analysis was used to determine the partial pair distributions, cation-oxygen bond lengths, co-ordination numbers and three-particle bond-angle distributions. The glass sample with 7.5 mol% SrO was transformed into the anti-glass phases by annealing at 350°C and into the crystalline phases by annealing of the anti-glass sample at 450°C. The crystal structure parameters of the anti-glass and crystalline samples were determined by Rietveld analysis and it was found that the anti-glass sample contains disordered SrTe5O11 and SrTeO3 phases, while the crystalline sample contains monoclinic SrTeO3 and orthorhombic TeO2 phases.