Abstract: A method of producing a dielectric layer made of a polycrystalline dielectric material having anisotropy in the coefficient of thermal expansion is provided, including the steps of providing a raw material powder, and heat treating the raw material powder at least to a temperature sufficient to cause a phase change from a first crystal orientation at room temperature to a different crystal orientation to provide an aggregate of oriented raw material particles having the same chemical composition as the raw material powder but having the different crystal orientation. The method also includes a step of forming a compact from the aggregate of oriented raw material particles, including a step of applying a shearing force to the aggregate and firing the compact to form the dielectric layer.

Abstract: A piezoelectric body is provided, including (Bi½Na½)TiO3 as a main component which is obtained by forming and sintering powders. A heterogeneous phase, other than (Bi½Na½)TiO3 system perovskite phase, in the powders has a peak ratio relative to the strongest peak of the perovskite phase of 5% or lower as determined by powder X-ray diffraction. As a result, the frequency of the dielectric breakdown in a sintered piezoelectric body during polarization can be dramatically reduced to 0.1 to 2% of that experienced in prior art compositions The manufacturing yield can be increased, manufacturing costs can be reduced, and the overall reliability of products manufactured therefrom can be improved.