Crystal-oriented ceramics, piezoelectric ceramics using the same, and methods for producing the same

摘要

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. The host material may be a magnetoplumbite-type-structured or Sr2Nb2O7-type-structured material, and may be composed of morphologically-anisotropic grains.