The Bi0.5Na0.5TiO3-xwt%BaTiO3 compound ceramics were prepared. The influence of different BaTiO3 content on structure was evaluated by scanning electron microscopy and X-ray diffraction analysis. The results show oriented is induced by plate-like BaTiO3 template. Signficant improvement of the piezoelectric (d33 = 112 pC/N) and dielectric properties ( max ≈ 5500) was observed. The improvement was attested to the apparent alignment of the BaTiO3 templates and grain oriented growth.

The dielectric response of [110]-oriented 0.68PMN-0.32PT single crystal under dc electric field has been investigated. The characteristics of phase transition under temperature and dc electric field are provided. When electric field is above 2.3kV/cm, abnormal phase transition is induced by temperature and electric field, which corresponds to the phase transition from rhombohedral to orthorhombic ferroelectric phase. With increasing dc electric field, the stable temperature region of orthorhombic phase is expanded. The electric field-temperature (E-T) phase diagram of [110]-oriented 0.68PMN-0.32PT single crystals is presented. The polarization rotation in [110]-oriented single crystal is discussed.

Ferroelectric ceramics, Sr1-xLaxBi2Nb2-x/5O9 (SLBNO), were prepared using the conventional solid-state reaction method. Effect of lanthanum substitution on dielectric and ferroelectric properties of SrBi2Nb2O9 (SBN) ceramics were investigated. X-ray diffraction analyses (XRD) revealed that all the specimens had a single phase with orthorhombic space group A21am. The maximum dielectric permittivity peak broadened gradually with the increase in lanthanum substitution indicated that the phase transition from normal ferroelectrics to relaxor ferroelectrics occurred in SLBNO ceramics. The modified Curie-Weiss (CW) law was used to describe the relaxor behavior of the SLBNO ceramics. The relaxation indication coefficient (γ) was estimated from a quadratic fit of modified CW law and was found to be 1.7 and 2.0 for the SLBN20 and SLBN30 specimens, respectively. Curie temperature (Tc) of the SBN ceramic was decreased gradually with the increase in lanthanum substitution. In addition, the ferroelectric properties of the SBN ceramic were enhanced significantly by the introduction of lanthanum ions and the maximum of remnant polarization (Pr) was found to be 4.35 μC/cm2 for the SLCB20 specimen. Nature of relaxor behavior of the SLBNO ceramic is attributed to the cationic disordering at nanoscale on A site by the introduction of lanthanum ions.

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