Investigation of Dielectric, Ferroelectric, and Strain Responses of (1 – x)[0.90(Bi0.5Na0.5)TiO3 – 0.10SrTiO3] – xCuO Ceramics

The low-temperature sintering of (Bi0.5Na0.5)TiO3-based ceramics can be achieved by sintering aid CuO. Piezoelectric ceramics (1 – x)[0.90(Bi0.5Na0.5)TiO3 – 0.10SrTiO3] – xCuO (BNT-ST-Cu) with x = 0, 0.01, 0.02, 0.03, and 0.04 were prepared through the mixed oxide route. A tetragonal structure was indexed for the undoped sample. Its structure was found to be changed to a pseudocubic when Cu was added. For undoped Cu samples, the sintering temperature (Ts) for sufficient densification was 1160 °C. However, Ts was reduced to 1090–1120 °C for Cu-added specimens. Field emission scanning electron microscopy (FE-SEM) showed a uniform and dense grain morphology for all samples. The maximum dielectric constant temperature (Tm) was decreased with the doping concentration of Cu and applied frequency. The strain was increased with Cu concentration and had the maximum value of 500 pm/V for the sample x = 0.02 with symmetric and slim strain loops.