Crystal phases and electric properties of (Na0.5K0.5)1−xNb1+x/5O3:yCuO, zLiSbO3 piezoceramics

In this study the electric property and the formation of crystal phases are characterized along with the increase of the A-site alkali deficiency(x) in the non-stoichiometric (Na0.5K0.5)1−xNb1+x/5O3:yCuO + zLiSbO3 (x = −0.01 to 0.1; y = 0, 0.01; z = 0, 0.05) ceramics. Quantitative crystal phase analysis has been carried out using Rietveld method. The crystal structure of tetragonal tungstenbronze phase is discussed in relation with the P–E hysteresis and dielectric properties. The stoichiometric and the slightly alkali deficient samples show very leaky P–E loop. With increasing the alkali deficiency the electrical leakage decreases and the P–E loop shows the saturation. CuO and LiSbO3 doping in the alkali deficient sample (x = 0.05, y = 0.01, z = 0) leads to the slim and pinched P–E loop shape. By CuO doping the Pr and Ps decreases to 13.9 and 20.87 μC/cm2 from 25.6 and 27.2 μC/cm2, respectively.