Piezoelectric element formation member, method of manufacturing the same, piezoelectric actuator unit and liquid ejection head incorporating the same

A piezoelectric element formation member, comprising:

• a substrate, in which first internal electrode layers and second internal electrode layers are alternately laminated while sandwiching piezoelectric material layer therebetween, the first internal electrode layers being exposed to a first end face of the substrate, and the second internal electrode layers being exposed to a second end face of the substrate which is opposite to the first end face;
• a first external electrode layer formed on the first end face and a third end face connecting the first end face and the second end face, the first external electrode layer being electrically connected to the first internal electrode layers;
• and
• a second external electrode layer formed on the second end face and the third end face, the second external electrode layer being electrically connected to the second internal electrode layers, and being electrically independent from the first external electrode layer, wherein:
• the first external electrode layer and the first internal electrode layers are to be divided by slits extending from the first end face to form a plurality of piezoelectric elements arrayed in a first direction;
• and
• the second external electrode layer includes:
• a pair of first sections provided on both end portions of the third end face in the first direction, and having a first dimension in a second direction perpendicular to the first direction;
• and
• a second section provided between the first sections, and having a second dimension in the second direction which is less than the first dimension.