1. Technical Field
The present invention relates to a piezoelectric element and a piezoelectric element-applied device that are excellent in displacement properties.
2. Related Art
In general, piezoelectric elements have a piezoelectric layer with electromechanical transducing properties and two electrodes holding the piezoelectric layer therebetween. In recent years, devices (piezoelectric element-applied devices) using such a piezoelectric element as a driving source have been increasingly developed. Examples of such a piezoelectric element-applied device under development include liquid ejecting heads represented by an ink jet recording head, MEMS devices represented by a piezoelectric MEMS device, ultrasonic measuring devices represented by an ultrasonic sensor or the like, and piezoelectric actuators.
A piezoelectric material used for such a piezoelectric layer is expected to have good piezoelectric properties, and as such a piezoelectric material, a composite oxide having a binary perovskite structure (perovskite composite oxides) containing lead titanate (PbTiO3, hereinafter, referred to as “PT”) and lead zirconate (PbZrO3, hereinafter, referred to as “PZ”), that is, lead zirconate titanate (Pb(Zr, Ti)O3, hereinafter, referred to as “PZT”) is widely known.
In recent years, multicomponent perovskite composite oxides containing a third component in PZT have also been developed, and as such a multicomponent PZT, PZT containing lead nickelate niobate (Pb(Ni, Nb)O3, hereinafter, referred to as “PNN”) as a third component (PNN-PZT) is known (e.g., refer to JP-A-11-129478 and JP-A-11-207957).
PNN-PZT, however, lacks sufficient displacement properties desired for higher performance and the like of various apparatuses having a piezoelectric element-applied device mounted therein and displacement properties comparable at least to those of PZT are needed. To obtain excellent displacement properties, selection of a substitution site and a substitution element of a perovskite composite oxide, substitution amount, and the like should be further reviewed for further optimization. Such a problem is not limited to that in piezoelectric elements mounted in ink jet recording heads, and similar problems arise in elements for piezoelectric MEMS devices, ultrasonic sensors, piezoelectric actuators, and the like.