Papers by Keyword: Domain Wall Engineering

Abstract: Grain-oriented barium titanate (BaTiO3, BT) ceramics were prepared by a templated grain growth (TGG) method using [110]-oriented BT platelike particles as a template and hydrothermal BT sphere particles with different particle sizes as a matrix. The degree of orientation along the [110] direction, F110, was measured using an X-ray diffraction (XRD) pattern by the Lotgering method. To obtain both a high density and a high F110, the preparation conditions were optimized as functions of matrix particle size, volume fraction of the template to the matrix, and sintering temperature. As for the results, BT grain-oriented ceramics with a high density of more than 96 % were successfully prepared despite various F110 values from 0 to 98 %. Scanning electron microscopy (SEM) revealed that their average grain sizes were always 75 µm despite various F110 values and there were no anisotropic microstructures. These grain-oriented BT ceramics were poled at 100 °C, and their piezoelectric constants d33 was measured. As for the results, the d33 values increased with increasing F110 values, and at around an F110 of 85 %, d33 reached a maximum of 788 pC/N.

Abstract: For the [111] oriented barium titanate (BaTiO3) single crystals, the patterning electrode was applied to induce the finer engineered domain configurations with domain size of 3 2m. The poling treatment was performed at 134 °C under electric fields below 6 kV/cm to inhibit the burning of the patterning electrode with photoresist. As the results, the gradient domain sizes from 3 to 8-9 2m were induced into the 31 resonator. The d31 was measured at -243.2 pC/N, and this value was almost 70 % of the expected d31 of –337.7 pC/N for the resonator with domain size of 3 2m. This difference was originated from lower applied electric field below 6 kV/cm. However, this study was revealed that the patterning electrode was very powerful tool to induce much finer domain sizes below 5 2m.