Structure, dielectric and optical properties of Nd 3+-doped LiTaO 3 transparent ferroelectric glass–ceramic nanocomposites

Abstract

Here, we present the structural, dielectric and optical properties of neodymium ion (Nd 3+) doped novel transparent glass-ceramics containing LiTaO 3 nanocrystals in the Li 2O–Ta 2O 5–SiO 2–Al 2O 3 (LTSA) glass system prepared by the melt-quenching technique. The precursor glasses were isothermally crystallized at 680 °C for 3–100 h, following the differential thermal analysis (DTA) data, to obtain nanostructured glass-ceramics. They were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), Fourier transform infrared reflection spectra (FTIRRS), optical absorption and luminescence spectroscopy along with dielectric constant measurements. XRD, FESEM, TEM and FTIRRS confirm the nanocrystallization of LiTaO 3 (14–36 nm) in the LTSA glass matrix. A steep increase in dielectric constant ( ɛ r) of glass-ceramics with heat-treatment time is observed due to high dielectric constant ferroelectric LiTaO 3 formation. The measured NIR photoluminescence spectra have exhibited emission transitions of 4F 3/2 → 4I J ( J = 9/2, 11/2 and 13/2) from Nd 3+ ions upon excitation at 809 nm. It is observed that the photoluminescent intensity and excited state ( 4F 3/2) lifetime of Nd 3+ ions decrease with increase in heat-treatment time due to concentration quenching effect. The absorption spectra and fluorescence measurements reveal that the incorporation of Nd 3+ ions in the LiTaO 3 crystal lattice in the oxide glassy matrix is important for obtaining desirable fluorescence performance of the material.