Patent ID: 8269402

Claim:
A piezoelectric/electrostrictive ceramic composition having a composition represented by the general formula: x(Bi 1/2 Na 1/2 )TiO 3 -y(Bi 1/2 K 1/2 )TiO 3 -zBaTiO 3 , wherein x+y+z=1, and wherein at least one kind among Bi, Na and K as A-site elements is 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 including a border line of a quadrangle ABCD with a point A (x=0.93, y=0, z=0.07), a point B (x=0.86, y=0, z=0.14), a point C (x=0.74, y=0.20, z=0.06) and a point D (x=0.80, y=0.20, z=0.00) as vertices in a ternary phase diagram, and thus a stoichiometrically deficient amount of the A-site elements is adjusted to at least 2 mol % to at most 6 mol %.