The additives for improving piezoelectric and ferroelectric properties of 0.2Pb(Mg1/3Nb2/3)O3–0.8[PbZr O3–PbTiO3] ceramics

The effects of CuO, ZnO, and Li2O (0.2wt.%) additions on the piezoelectric and ferroelectric properties of 0.2Pb(Mg1/3Nb2/3)O3–0.8Pb(Zr0.475Ti0.525)O3 (designated as PMNZT) ceramics were investigated. The density of sintered sample was strongly affected by small amounts of CuO, ZnO, and Li2O addition. From the X-ray diffraction analysis, single phase of polycrystalline Perovskite was confirmed. The dielectric and piezoelectric constants of PMNZT ceramics doped with CuO, ZnO, and Li2O were higher than that of pure ones. The improvement of piezoelectric properties was maximized at various 0.2 wt.% doped PMNZT samples. The maximum dielectric constant (εr=1423) and minimum dielectric loss (tan δ=0.0019) at room temperature were obtained with Li2O addition. The electromechanical coupling factor, k33 of 0.2 wt.% of CuO, ZnO, and Li2O doped and pure PMNPZT ceramics were found to be 0.72, 0.68, 0.75, and 0.20, respectively. And the piezoelectric constant, d33 of CuO, ZnO, and Li2O doped and pure ceramics were found to be 330, 332, 418, and 95 pC/N, respectively. These values are comparable to that of pure ones and we will discuss which impurity would be the best dopant to improve the piezoelectric and dielectric constants of pure sample.