Structural and spectroscopic study of oxyfluoride glasses and glass-ceramics using europium ion as a structural probe

• Published in: Journal of physics. Condensed matter 2008-04, Vol.20 (14), p.145201-145201 (7)
• Main Authors: Bueno, L A, Gouveia-Neto, A S, da Costa, E B, Messaddeq, Y, Ribeiro, S J L
• Format: Article
• Language: English
• Subjects: Amorphous materials, glasses and other disordered solids; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from solid phases (including multiphase diffusion and recrystallization); Materials science; Methods of crystal growth; physics of crystal growth; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/20/14/145201

Transparent oxyfluoride glasses and beta-PbF2 nanocrystals containing glass-ceramics were prepared with varying Eu3+ content (0.,0.,0.5 and 0.6%). The effect of Eu3+ content on the preparation of glass-ceramics was investigated. From differential scanning calorimetry, the Tx-Tg (Tx-temperature of the onset of crystallization; Tg-glass transition temperature) parameter for glasses has shown slight variation, and an exothermic peak near Tg called the ceramization temperature (Tc) has been observed. Heat treatments were performed at this temperature to obtain transparent glass-ceramics containing beta-PbF2 nanocrystals, identified by x-ray diffraction. Heat treatments for different periods of time were performed and were observed to be very important in the control of the crystal size and of the crystallization rate. Based upon the absorption spectra, the scattering level due to the presence of beta-PbF2 nanocrystals in the glass-ceramics was observed to be similar to that for the mother glasses. Detailed analysis of emission spectra and decay time measurements led to the identification of Eu3+ ions as the beta-PbF2 crystalline phase. Excitation spectra at 70 K show the interaction of Eu3+ ions with the fluorogermanate network.