Abstract: A crystal-oriented ceramic has an isotropic or pseudoisotropic perovskite-type-structure of not smaller than 10% in Lotgering orientation degree. The ceramic may contain at least one of Bi, Sr and Ca. A host material, a raw material capable of producing a guest material and an additive having the ability of converting a host material into a guest material are mixed and roll-pressed, and sintered under heat to give the crystal-oriented ceramic as a large-sized and bulky material. This crystal-oriented ceramic has good crystal orientation-dependent characteristics including piezoelectricity, pyroelectricity, ionic conductivity, giant magneto-resistivity effect, etc. This crystal-oriented ceramic can be produced by orienting epitaxially the polycrystals of an isotropic or pseudoisotropic perovskite oxide according to the orientation of the crystal plane or axis of a host material. The ceramic can be applied to an inexpensive and large-sized device.

Abstract: This invention provides a piezoelectric ceramic composition having large field-induced strain under high compressive stress, small temperature dependence of strain, and high energy conversion efficiency even at high temperatures. The composition is represented by;(Pb.sub.1-(3X/2)-(U/2) La.sub.X)((Zr.sub.Y Ti.sub.1-Y).sub.1-Z-U (Mg.sub.1/3 Nb.sub.2/3).sub.Z Nb.sub.U)O.sub.3where 0<X<2/3; 0<U<1; 0.53-(Z/3).ltoreq.Y.ltoreq.0.56-(Z/3); and 0.02.ltoreq.Z.ltoreq.0.10. In this composition, a part of the crystals of PZT has been substituted by La and Nb and further by a suitable amount of PMN. These substituents play complementary roles to each other to impart aforementioned excellent properties to the ceramic composition.