Piezoelectric element and method for producing the same, liquid ejection head, and printer

A method for producing a piezoelectric element, comprising:

• forming a first electrode above a base body;
• forming a first piezoelectric layer so as to be in contact with the base body and cover the first electrode;
• forming a second piezoelectric layer above the first piezoelectric layer;
• and
• forming a second electrode above the second piezoelectric layer, wherein
• the first piezoelectric layer includes a composite oxide that contains potassium and niobium and that has a perovskite-type structure containing potassium as a main component at an A-site,
• the second piezoelectric layer includes a composite oxide that contains potassium, sodium, and niobium and that has a perovskite-type structure, and
• a local maximum value of potassium atomic concentration (atm %) in the first piezoelectric layer is higher than a local maximum value of a potassium atomic concentration (atm %) in the second piezoelectric layer.

A piezoelectric element, comprising:

• a first electrode provided above a base body;
• a first piezoelectric layer provided so as to be in contact with the base body and cover the first electrode;
• a second piezoelectric layer provided above the first piezoelectric layer;
• and
• a second electrode provided above the second piezoelectric layer,
• wherein the first piezoelectric layer includes a composite oxide that contains potassium and niobium and that has a perovskite-type structure containing potassium as a main component at an A-site,
• the second piezoelectric layer includes a composite oxide that contains potassium, sodium, and niobium and that has a perovskite-type structure,
• the first piezoelectric layer has a higher potassium atomic concentration (atm %) than the second piezoelectric layer,
• in an X-ray diffraction pattern of the second piezoelectric layer, a ratio of a (100) plane peak intensity to a sum of the (100) plane peak intensity and a (110) plane peak intensity is 0.75 or more.