Patent ID: 7414352

Claim:
A piezoelectric/electrostrictive body comprising a large number of crystal grains having piezoelectric/electrostrictive properties and being one of: (1) a PbMg 1/3 Nb 2/3 O 3 —PbZrO 3 —PbTiO 3 ternary solid solution system composition represented by the formula Pb x (Mg y/3 Nb 2/3 ) a Ti b Zr c O 3 , wherein 0.95≦x≦1.05, 0.8≦y≦1.0, and a, b, and c are decimals (additionally, a+b+c=1.00) in a range surrounded with (a, b, c)=(0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0.300), (0.050, 0.425, 0.525), (0.050, 0.525, 0.425), (0.375, 0.425, 0.200) in a coordinate including three coordinate axes of a, b, and c; (2) a lead titanate zirconate containing as a main component the PbMg 1/3 Nb 2/3 O 3 —PbTiO 3 ternary solid solution system composition in (1) and containing 0.05 to 3% by mass of NiO; and (3) a Pb(Mg, Ni) 1/3 Nb 2/3 O 3 —PbZrO 3 —PbTiO 3 ternary solid solution system composition represented by the formula Pb x {(Mg 1-y Ni y ) (1/3) x a Nb 2/3 } b Ti c Zr d O 3 , wherein 0.95≦x≦1.05, 0.05≦y≦0.20, 0.90≦a≦1.10, and b, c, and d are decimals (additionally, b+c+d=1.00) in a range surrounded with (b, c, d)=(0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0.300), (0.050, 0.425, 0.525), (0.050, 0.525, 0.425), (0.375, 0.425, 0.200) in a coordinate including coordinate axes of b, c, and d, wherein the crystal grains are arranged in a film or layer having a thickness direction and a width direction perpendicular to the thickness direction, wherein each of the crystal grains, as observed in an arbitrary section in the thickness direction of the film or layer, has a width measured along the width direction of the film or layer, and has a thickness measured along the thickness direction of the film or layer, wherein the width of each crystal grain is greater than the thickness thereof in a portion of the large number of crystal grains, and wherein a number ratio of the portion to the large number of crystal grains is 70% or more as observed in the arbitrary section in the thickness direction of the film or layer.