Non-contact localized probing of ferroelectric phase transitions in Li+/Er3+:BaTiO3 ceramics using fluorescence abnormalities.

Fluorescence abnormalities associated with the ferroelectric phase transition of Li+/Er3+:BaTiO3 (BLET) ceramics were studied based on photoluminescence (PL) spectra. Sharp changes were found in the integrated intensities, peak intensities, and fluorescence intensity ratios of both upconversion spectra (2H11/2/4S3/2−4I15/2) and downconversion infrared spectra (4I13/2−4I15/2) around the ferroelectric-paraelectric phase transition temperature in BLET ceramics under the excitation of a 980 nm laser. All changes happened within the temperature interval of 126 °C–130 °C. The relative changing rate (RCR) was adopted to quantitatively describe this structure-sensitive PL. For the system under study, the maximum RCR occurs for the PL peak intensity at 542.7 nm. [ABSTRACT FROM AUTHOR]