The dielectric properties at microwave frequencies of Ba(Zn,,,Ta,,,)O, ceramics prepared by sintering were investigated. These ceramics had lower density but higher loss quality than ceramics hot-pressed at 1400°C. Loss quality was greatly improved by prolonged sintering. The Q of the ceramics measured by the dielectric resonator method was 14000 at 12 GHz. The ceramics were investigated by X-ray diffraction analysis. It was found that Q improvement corresponds with increased Zn and Ta ordered structures in the ceramics.

Highly c-axis oriented and epitaxial PbTiO3 thin films were grown on MgO single crystals and epitaxial Pt film substrates by the rf-magnetron sputtering method. The films with a 98% c-axis orientation rate were obtained under low deposition rate (<20 Å/min) and low gas pressure (∼1 Pa) using a PbO-rich target. Phase transition of the PbTiO3 thin film was studied by high-temperature x-ray diffraction. It was found that the c-axis of the tetragonal phase was parallel to the substrate just below Tc and the c-axis becomes perpendicular to the substrate with lowering of temperature. These films show high resistivity (∼1010/Ω cm). It was found that significant pyroelectric currents are detected on all specimens without poling treatment. The polarization directions of the films are the same in all specimens. One of these films had a low relative dielectric constant of 97 and a high pyroelectric coefficient of 2.5×10−8 C/cm2 K without poling treatment. These films will be suitable for applications such as pyroelectric infrared detector and piezoelectric transducer.

Piezoelectric properties have been studied on ferroelectric ceramics comprising bismuth compounds with layer structure, PbBi2Nb2O9, PbBi4Ti4O15, SrBi4Ti4O15 and Na0.5Bi4.5Ti4O15. These ceramics have the high mechanical quality factor Q(2000∼7200), low aging rate of frequency constant Nt(30∼60 ppm/time decade), low temperature coefficients both of Nt(-50 ppm/°C) and of coupling factor kt(70 ppm/°C), low Poisson's ratio σ(0.23∼0.27), and large anisotropy in coupling factor. A small value of kt in these ceramics probably relates to two-dimensional restriction on permissible rotation of the spontaneous polarization. The poling characteristics in the ceramics can be improved by some additives. Grain boundaries in these ceramics are of nearly rectangular shape, and an etch pattern of fine stripes appears always in parallel to the length of the boundary.

Using an rf-magnetron sputtering method, highly c-axis-oriented La-modified PbTiO3 (PLT) thin films with compositions of Pb1−xLaxTi1−x/4O3, where x=0.05, 0.10, and 0.15, have been obtained on MgO single-crystal and epitaxial Pt thin-film substrates under conditions of low gas pressure and low deposition rate. The degree of c-axis orientation of the PLT films decreases, and the tetragonality of PLT becomes smaller with increasing La content. The Curie point of the films decreases at a rate of 18 °C/at. % of La with an increase of La content. D-E hysteresis loops were observed, and these became slim and symmetric with increasing La. It was found that significant pyroelectric currents are detected on all as-grown specimens even without a poling treatment, and the directions are the same in all specimens. Relative dielectric constant εr decreases, and pyroelectric coefficient γ increases with increasing degree of c-axis orientation. εr and γ became large with increase of La content in the films. Considering the figure of merit for pyroelectric infrared detection and the temperature coefficient of γ, it was concluded that PLT films with x=0.10 were good material for pyroelectric infrared detectors.

A piezoelectric ceramic material having low dielectric constant, high thickness coupling factor, high mechanical quality factor, high stability, and high operating temperature, has been prepared from PbTiO3 incorporated with 2.5 mol% of LaO12 and 1.0 mol% of MnO2. Typical electromechanical constants of this material are as follows: dielectric constant ε11T/ε0 230, ε33T/ε0 170; coupling factor k33 0.46, kt 0.46, k15 0.28, kp 0.07, k31 0.04; mechanical quality factor Q 1100, Poisson's ratio σE 0.20. Frequency constants Nt and N3t of the fundamental and third-harmonic thickness vibrations have temperature coefficients of −1.1 × 10−4°C−1 and −2 × 10−5°C−1, respectively. Aging rates of Nt and N3t, are +0.02% and −0.02%/time decade at 30°C, respectively. The Curie point of this material exists at 470°C, and k33 and kt increase gradually with temperature up to 400°C. This material has grain size of 2–3 μ and bending strength of 2 × 107 kg/m2, and can be polished into very thin plate. The PbTiO3 ceramics have a high potential for use in electromechanical devices at high frequency and high temperature.