Patent ID: 8177995

Claim:
A piezoelectric oxide having a composition expressed by a compositional formula, (Ba, Bi, A)(Ti, Fe, M)O 3 , where each of A and M represents one or more metal elements other than Pb; Ba, Bi, and A are A-site elements, Ti, Fe, and M are B-site elements, Ba, Bi, Ti, Fe and O respectively represent barium, bismuth, titanium, iron, and oxygen, the one or more B-site elements represented by M are elements other than Ti and Fe when the one or more A-site elements represented by A are Ba and/or Bi, the one or more A-site elements represented by A are elements other than Ba and Bi when the one or more B-site elements represented by M are Ti and/or Fe, and the ratio of each of the total molar amount of the A-site elements and the total molar amount of the B-site elements to the molar amount of oxygen may deviate from 1:3 within a range in which the composition expressed by the compositional formula (Ba, Bi, A)(Ti, Fe, M)O 3 can form a perovskite structure; the composition of the compound (Ba, Bi, A)(Ti, Fe, M)O 3 is determined so as to satisfy the conditions (1) and (2), 0.98≦TF(P)≦1.02, and (1) TF(BiFeO 3 )<TF(AMO 3 )<TF(BaTiO 3 ), (2) where TF(P) is a tolerance factor of the piezoelectric oxide expressed by the compositional formula (Ba, Bi, A)(Ti, Fe, M)O 3 , TF(BaTiO 3 ) is a tolerance factor of a compound expressed by a compositional formula BaTiO 3 , TF(BiFeO 3 ) is a tolerance factor of a compound expressed by a compositional formula BiFeO 3 , and TF(AMO 3 ) is a tolerance factor of a compound expressed by a compositional formula AMO 3 .