Rare-earth fluorescence in Raman microprobe spectra of glasses and ceramics

Abstract

We are reporting on spectroscopic observations, made with the Raman microprobe, of fluorescence emissions by several rare earth, or lanthanide ions (Ln3+), in several types of ordered and disordered solids. These studies are an extension of earlier work on the luminescence properties of mainly two ions, Eu3+ and Er3+, as components of silicate glasses and of various ceramics related to high-temperature superconducting systems. Concerning the Y-Ba-Cu-O system, where yttrium has been replaced by one of the lanthanide elements (Ln = Nd, Sm, Eu, Dy, Ho, Er), our aim is to relate the observed optical spectra (Raman and fluorescence) to the composition and structure of the solids derived from the phase diagram. For this system, the Raman spectra of most of the compounds are well understood. Much less is known about the fluorescence spectra of the rare-earth substituted analogs and their relation to composition and structural order. The luminescence emissions of many of the Ln3+ ions can serve as useful spectroscopic probes of the structure of the host compound, of differences in bonding, and in the charge environment.