Piezoelectric/electrostrictive ceramics composition, piezoelectric/electrostrictive ceramics sintered body, piezoelectric/electrostrictive element, manufacturing method of piezoelectric/electrostrictive ceramics composition, and manufacturing method of piezoelectric/electrostrictive element

摘要

[Object] To provide piezoelectric/electrostrictive ceramics and a piezoelectric/electrostrictive element with a large electric field-induced strain without performing an aging treatment. [Solving Means] Piezoelectric/electrostrictive ceramics have the composition represented by the general formula: xBNT-yBKT-zBT (x + y + z = 1) wherein at least one kind among A-site elements are allowed to become deficient from stoichiometry in which a point (x, y, z) representing content ratios x, y and z of (Bi 1/2 Na 1/2 )TiO 3 , (Bi 1/2 K 1/2 )TiO 3 and BaTiO 3 is within a range (also including a border line) of a quadrangle ABCD with a point A, a point B, a point C and a point D as vertices in a ternary phase diagram. Vacancies are formed in an A-site of a perovskite structure by allowing the A-site elements to become deficient from stoichiometry. An amount of A-site vacancies becomes at least 2 mol% to at most 6 mol%.