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Ultrafine PbTiO/sub 3/ (PT) powder has been prepared using the sol-gel process. PT/epoxy 0-3 composites have been prepared by application of an external DC electric field during solidification of the epoxy. The structure and optical properties of the composite materials prepared under various electric fields have been carefully analyzed by XRD (X-ray diffraction) and optical spectroscopy techniques such as ultraviolet absorption spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. Second harmonic generation by the composite has also been observed. The effect of the electric field on the structure and optical properties of the composites is discussed. >

Electromechanical resonances of ceramic multilayer capacitors are calculated mechanically free and clamped boundary conditions using vibration and piezoelectric equations. BaTiO/sub 3/-based and Pb(Mg/sub 1/3/Nb/sub 2/3/)O/sub 3/-based multilayer capacitors have been used to check the theoretical calculation. Frequency spectra of impedance and phase angle, capacitance, and loss tangent of the capacitors under DC bias fields were carefully measured. A sudden change around the resonant frequency is observed in these spectra. A damped resonance indicates a defective capacitor while an undamped resonance corresponds to a defect-free one. Experimental results suggest that it is possible to use the spectra as a real-time nondestructive evaluation method. >

Ultrafine PT (lead titanate) powders were dispersed in different liquids to form uniform suspensions of ferrofluids. PT powders in ellipsoidal and needle like morphologies derived from the sol-gel process and hydrothermal synthesis were suspended in organic solvents. Nonlinear optical properties such as second harmonic generation and degenerate four-wave mixing (DFWM) and the Raman spectra were investigated. The microstructures of the powders were analyzed on the basis of the Raman spectra. Phase conjugation via DFWM was examined. Changes of optical properties under application of a bias electric field to the samples are shown. The vibration modes are shown to be different for different PT powder shapes and sizes. More vibration modes in the long wavenumber region are damped in larger needle-like PT powders. The spontaneously polarized PT powders and suspensions possess second-order and third-order nonlinearities. Needle-like PT powders are better for the control of alignment in some liquids. >

Lead lanthanum zirconate titanate (PLZT) films were deposited by the metallorganic decomposition (MOD) process using multilayer spinning. The crystallization kinetics, the evolution of the crystallographic structure, the dielectric behavior, and the ferroelectric properties were studied. It was found that a perovskite structure crystallizes from decomposed amorphous precursors in the temperature range 420-570 degrees C. A metastable pyrochlore phase always forms during the crystallization of the films from the amorphous phase, with an activation energy and a frequency factor of 143 kJ/mol and 7.9*10/sup 9/ s/sup -1/, respectively. Two modifications of the perovskite structure can be obtained for PLZT(8/0/100). One is rhombohedral with a=0.3948 nm and alpha =89.61 degrees for annealing in air at 550 degrees C; the other is tetragonal with a=0.3909 nm, c=0.4046 nm, and c/a=1.035. >