Influence of Eu2O3 on phase crystallization and nanocrystals formation in tellurite glasses

• Published in: Journal of non-crystalline solids 2018-11, Vol.499, p.49-57
• Main Authors: García-Amaya, I.V., Zayas, Ma.E., Alvarado-Rivera, J., Cortez-Valadez, M., Pérez-Tello, M., Cayetano-Castro, N., Martínez-Suárez, F., Mendoza-Córdova, A.
• Format: Article
• Language: English
• Subjects: Crystal growth; Nanocrystals; Rare-earth doped glasses; Tellurite glasses
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2018.07.018

Glasses of the 17ZnO·32CdO·51TeO2 system doped with Eu2O3 (0–0.75 mol per 100 mol of oxides) were obtained. Non-isothermal differential scanning calorimetry (DSC) tests showed that the glass transition temperature varied in the range of 354° to 371 °C with the addition of Eu2O3. The samples were exposed to a thermal treatment in a laboratory oven at 420 °C. X-ray diffraction analysis of the treated samples showed crystalline phases of a variety of metallic oxides, the intensities of which decreased as the Eu doping amount in the samples increased. In all samples, the strongest peak corresponded to ZnTeO3 with a crystallite size of about 36 nm. Fourier Transform Infrared Spectroscopy showed that CdO and ZnO change their role from modifier to a glass former. Raman spectra showed characteristic bands corresponding to γ–TeO2. The observations suggest that Eu2O3 induced structural changes which in turn led to the formation of molecular oxygen in the interstitial network. Deconvolution analysis of Raman spectra and High-Resolution Transmission Electron Microscopy images confirmed the formation of Te2O5, ZnTeO3 and Te nanocrystals. Photoluminescence analysis showed that Eu ions are incorporated as Eu3+ and no reduction occurred after heat treatment. •Heat treatment at 420 °C leads to crystallization of ZnTeO3 nanocrystals and several phases.•Raman spectra revealed the presence of interstitial molecular oxygen in the glass.•Eu2O3 concentration increment decreases the formation of crystalline phases.•Photoluminescence shows that Eu3+ ions are not reduced after heat treatment.