Glass-forming ability of rare earths in fluorozirconate glasses

Abstract

The effects of rare earth elements on glass formation regions in the systems ZrF 4BaF 2LnF 3AlF 3 (Ln is a rare earth element and AlF 3 concentration is 4 mol%) has been examined. It is found that glass formation regions gradually shift to higher concentrations of rare earth fluoride with decreasing rare earth element radius. As a result of measurements of optical absorption, luminescent and electron-phonon spectra of Eu 3+ ions as local probes of the glass structure in the system 55(mol%)ZrF 435BaF 25LnF 34AlF 31EuF 3 (Ln = La, Eu, Gd, Tb, Dy, Yb), it is determined that 5D 0− 7F 2 and 7F 0− 5D 2, supersensitive electronic transitions, intensities of Eu 3+ ions decreased with decreasing rare earth elements radius. In total, the results obtained indicate that the increasing glass-forming ability of rare earth fluorides in La to Lu rank is explained by the increasing degree of LnF bond covalency.