Patent ID: 8789927

Claim:
A piezoelectric element comprising: a piezoelectric layer; and a pair of electrodes associated with the piezoelectric layer, wherein the piezoelectric layer contains bismuth sodium potassium titanate and satisfies the inequality 0≦Pr/Pm≦0.25 at 25° C., where P m and P r are the saturation polarization and remanent polarization, respectively, of the piezoelectric layer, and wherein the piezoelectric layer contains bismuth sodium potassium titanate represented by the following formula: { x [(Bi a ,Na 1-a )TiO 3 ]-(1- x )[(Bi b ,K 1-b )TiO 3 ]} where, 0.4<a<0.6, 0.4<b≦0.6, and 0.5≦x≦0.85.