Murata Manufacturing Co., Ltd.

Yoichi Deguchi

Atsushi Yamamoto

Koichi Hayashi

A multilayer piezoelectric device including a body having internal electrode layers and piezoelectric ceramic layers alternately stacked. The internal electrode layers contain Cu as a major component, the piezoelectric ceramic layers contain a compound oxide represented by Pb(Ti, Zr)Oas a major component, and a metal oxide (NbO, SbO, TaO, or WO) containing Nb, Sb, Ta, or W, which is at least one of a pentavalent metal element and a hexavalent metal element, is incorporated in the piezoelectric ceramic layers such that the concentration of the metal oxide decreases with distance from the internal electrode layers. Thereby, even in a case where internal electrodes contain Cu as a major component, it is possible to provide a multilayer piezoelectric device which can be obtained by low-temperature firing while ensuring a sufficient piezoelectric constant.

Laminated piezoelectric element and process for producing the same

A piezoelectric device is formed by simultaneously firing a piezoelectric ceramic mainly composed of a perovskite complex oxide represented by general formula ABOand electrodes mainly composed of copper. The piezoelectric ceramic is represented by PbMe[(MM)TiZr]O(wherein Me represe element, Mis an acceptor element which is a divalent metal element, and Mis a donor element which is a pentavalent metal element), and satisfies equations 0.05&#x2266;z&#x2266;0.40, 0&#x3c;bz/3&#x2266;0.035, 0.345&#x2266;x&#x2266;0.480, 0.965&#x2266;&#x3b1;&#x2266;1.020, and 0&#x2266;a&#x2266;0.05. In other words, the B sites contain excessive donors, and thus a piezoelectric device having good piezoelectric characteristics can be obtained even in the cases where a base metal material mainly composed of inexpensive copper is used as the internal electrode material.

Growing community of inventors

Yasu, Japan

Yoichi Deguchi