The effect of (Mg1/3Ta2/3)4+ on the structure, Raman vibration, Terahertz time domain spectroscopy and dielectric properties for the Li2TiO3 ceramic

Abstract

The ceramics of Li2Ti1-x(Mg1/3Ta2/3)xO3 (x = 0.00–0.30) (LTMTx) were fabricated via the solid-phase method. The changes in crystal structure of LTMTx ceramics were confirmed by the X-ray diffraction (XRD). The microstructure of LTMTx ceramics was observed by the scanning electron microscope (SEM). The evolution of crystal structure and vibration for chemical bonds of LTMTx ceramics were studied by Raman spectra. The improvement on quality factors (Q × f values) was related to the weakening of asymmetric vibration in Li–O–Li bond. Based on the THz time domain spectrum (THz-TDS), the polarization mechanism and dielectric properties in THz frequency band were discussed. The satisfactory quality factor (80,005 GHz) was acquired in LTMT0.15 ceramic, and the best resonant frequency temperature coefficient (τf) value (0 ppm/°C) was achieved at x = 0.25, which firmly improved the application potential of LTMTx ceramics.