Photoluminescence studies on rare earth titanates prepared by self-propagating high temperature synthesis method

Abstract

The laser-induced luminescence studies of the rare earth titanates (R 2Ti 2O 7) (R = La, Nd and Gd) using 355 nm radiation from an Nd:YAG laser are presented. These samples with submicron or nanometer size are prepared by the self-propagating high temperature synthesis (SHS) method and there is no known fluorescence shown by these rare earths in the visible region. Hence, the luminescence transitions shown by the La 2Ti 2O 7 near 610 nm and Gd 2Ti 2O 7 near 767 nm are quite interesting. Though La 3+ ions with no 4f electrons have no electronic energy levels that can induce excitation and luminescence processes in the visible region, the presence of the Ti 3+ ions leads to luminescence in this region.