| 摘要 |
A head 5 has a base 21 and a piezoelectric element 23 which is superimposed on and fastened to the base 21 in a thickness direction. The piezoelectric element 23 has a plate-shaped piezoelectric body 41, and a common electrode 39 and a individual electrode 43 arranged so as to sandwich the piezoelectric body 41 in the thickness direction. The base 21 has a higher thermal expansion coefficient than the piezoelectric body 41 (the piezoelectric element 23), the piezoelectric body 41 has a tetragonal principal crystal phase, in which the degree of orientation of the c-axis toward one side in the thickness direction (positive side in z direction) in the region sandwiched by the common electrode 39 and the individual electrode 43 is 44% or more and 56% or less in terms of the Lotgering factor and in which the residual stress in the surface direction is 0MPa or more and 35 MPa or less in the direction of compression. |
