Erbium-doped LAS glass ceramics prepared by spark plasma sintering (SPS)

Dense nanocrystalline glass ceramics of the Li2O–Al2O3–SiO2 (LAS) system were obtained by spark plasma sintering (SPS) of powders prepared by sol–gel method. The low thermal expansion LAS glass ceramic was chosen as host matrix for erbium ions. ZrO2 was added both as a nucleating agent and as a possible good environment for the rare earth. The developed crystalline phases were analysed by X-ray diffraction (XRD) and the amorphous phase was quantified. Scanning and transmission electron microscopy (SEM, TEM) was used to investigate the microstructure. A different behaviour during the crystallisation process was observed between the sample prepared through the sintering of powders and the glass produced by the melting technique. A photoluminescence characterisation was also performed.