Microstructure, Raman spectroscopy, THz time domain spectrum and microwave dielectric properties of Li2Ti1-(Zn1/3Ta2/3) O3 ceramics

Li2Ti1-x(Zn1/3Ta2/3)xO3 (0.00 ≤ x ≤ 0.30) (LTZTx) ceramics were successfully prepared by the traditional solid phase method. The order-disorder phase transition for LTZTx ceramics was detected by the X-ray diffractometer (XRD). The scanning electron microscope (SEM) was used to measure the microstructure for LTZTx ceramics. The evolution in crystal structure for LTZTx ceramics was studied by Raman spectroscopy. The reduction of dielectric loss for LTZTx ceramics was caused by the weakening of asymmetric vibration in Li–O bond. The excellent dielectric properties (εr = 18.69, Q×f = 97,763 GHz, τf = +11.08 ppm/°C) were obtained in the LTZT0.15 ceramic fired at 1250 °C. Besides, by the addition of 5 wt % LiF, the sintering temperature of LTZT0.15 ceramic was reduced. The optimal dielectric properties (εr = 19.4773, Q×f = 102,531 GHz, τf = - 8.08 ppm/°C) of LTZT0.15 + 5 wt % LiF were obtained at 1100 °C. The THz time domain spectrum (THz-TDS) was implemented to investigate the polarization mechanism and dielectric properties during 0.5–1.5 THz. The LTZT0.15 and LTZT0.15 + 5 wt % LiF ceramics still own the high Q×f values at the band of THz, which is expected to be used in the future of 6G communication.