Effect of Oxide Doping on Electrical Properties of Tetragonal Perovskite Pb(Ni_1/3Nb_2/3)O₃-PbTiO₃ Ferroelectric Ceramics

Abstract

Pure and 1mol% La₂O₃-, Y₂O₃-, ZnO-, MnO₂- and Nb₂O₅-doped 0.58Pb(Ni_1/3Nb_2/3)O₃-PbTiO₃ (0.58PNN-0.42PT) ferroelectric ceramics were prepared by conventional ceramic processing via the columbite precursor route. XRD measurement confirmed that phase-pure tetragonal perovskites can be obtained in the pure and oxide-doped 0.58PNN-0.42PT ceramics sintered at 1180°C for 2 h except that the Y₂O₃-doped 0.58PNN-0.42PT ceramics contain slight content of pyrochlore phase. Oxide doping improves densification of the 0.58PNN-0.42PT ceramics, especially for the Y₂O₃-, ZnO- and MnO₂-doped ones whose relative density is larger than 95%. Oxide doping decreases dielectric constant of 0.58PNN-0.42PT slightly accompanied by the decrease of the temperature of dielectric maximum (T_C or T_m) and great broadening of the dielectric response peaks where frequency dependent dielectric behavior is apparent around the temperature range of T_m. All the oxide-doped 0.58PNN-0.42PT ceramics exhibit fat and nearly rectangular shape P-E hysteresis loops accompanied by large value of saturation polarization P_s. The Nb₂O₅-doped 0.58PNN-0.42PT ceramics exhibit the largest value of remanent polarization P_r of 19.43μC/cm² and the La₂O₃-doped 0.58PNN-0.42PT ceramics exhibit the least value of coerce field E_c of 7.14kV/cm. Piezoelectric constant d₃₃ of the 0.58PNN-0.42PT ceramics decreases slightly by oxide doping, where the La₂O₃-doped 0.58PNN-0.42PT ceramics exhibit the largest value of d₃₃, being 298pC/N.

Keywords:

• Lead nickel niobate-lead titanate
• perovskite
• dielectric property
• ferroelectric property
• piezoelectricity property

Acknowledgments

The authors thank the International Scientific Cooperation Project of Changzhou Scientific Bureau (Grant No. CZ2008014) and the Natural Science Fundamental Research Project of Jiangsu Colleges and Universities (Grant No. 08KJB430001) for financial support.