The piezoelectric properties of (1−x) Pb(Mg1/3Nb2/3)O3–xPbTiO3 (x=0.3–0.35), ceramics with a high degree of 〈001〉 fiber texture were investigated for possible actuator applications. Piezoelectric coefficients (d33) in excess of 1200 pC/N associated with strain levels up to >0.3% were observed in samples prepared by a reactive templated grain growth process. No excess PbO was used in the starting composition. A high degree of fiber texture was achieved using 〈001〉 oriented BaTiO3 template particles in a fine-grained precursor for the PMN–32PT matrix. High densities together with texture resulted in a significant increase in strain levels and d33 values compared to their polycrystalline counterparts. Peak dielectric constants on the order of 22 000 with losses of ∼2% and well-saturated hysteresis loops with a Pr∼27 μC/cm2 were recorded on the textured samples. These domain engineered, textured ceramics have tremendous potential for high-performance actuators.

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We have studied phase transitions in epitaxial BaTiO 3 thin films by Raman spectroscopy. The films are found to remain in a single ferroelectric phase over the temperature range from 5 to 325 K. The lowtemperature phase transitions characteristic of bulk BaTiO 3 ͑tetragonal-orthorhombic-rhombohedral͒ are absent in the films. X-ray diffraction shows that the BaTiO 3 films are under tensile strain due to the thermal expansion mismatch with the buffer layer. A phase-field calculation of the phase diagram and domain structures in BaTiO 3 thin films predicts, without any priori assumption, that an orthorhombic phase with in-plane polarization is the thermodynamically stable phase for such values of tensile strain and temperature, consistent with the experimental Raman results.

Complex impedance spectroscopic data were acquired on single crystals of the morphotropic phase boundary composition of 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 over a wide range of temperatures (25–525 °C) and frequencies 1 kHz–1 MHz. This study takes advantage of plotting ac data simultaneously in the form of impedance and modulus spectroscopic plots. This permits the easy interpretation of microscopic processes responsible for the measured ac response. Frequency explicit plots of imaginary components of impedance and modulus exhibit Debye-like peak shapes. The data for ac conductivity were computed from the impedance data and the activation energy for conduction at different frequencies was determined. Cole–Cole diagrams were plotted and these indicate the presence of a single relaxation process. The relaxation times determined from these plots followed an Arrhenius law, and the activation energy for relaxation was found to be 1.2 eV. The ac conductivity data was found to obey Jonscher’s universal power law and resulted in a value of the exponent “n”=0.95.

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