Patent ID: 7399066

Claim:
A piezoelectric element comprising a vibrating plate, a lower electrode, a piezoelectric film and an upper electrode laminated in this order, wherein the lower electrode, the upper electrode and the piezoelectric film are formed of a perovskite type oxide while the vibrating plate is formed of a perovskite type metal oxide, the piezoelectric element includes (i) between the vibrating plate and the lower electrode, a region where a substance constituting the vibrating plate and a substance constituting the lower electrode are mixed, (ii) between the lower electrode and the piezoelectric film, a region where a substance constituting the lower electrode and a substance constituting the piezoelectric film are mixed, and (iii) between the piezoelectric film and the upper electrode, a region where a substance constituting the piezoelectric film and a substance constituting the upper electrode are mixed, a junction interface is substantially absent between the vibrating plate and the lower electrode, between the lower electrode and the piezoelectric film, and between the piezoelectric film and the upper electrode, each of the regions (i), (ii) and (iii) has a perovskite crystal structure, and each of the lower electrode and the upper electrode is independently formed by M1RuO 3 (M1 being at least one selected from a group consisting of Sr, Ba and Ca) or Sr (1-x) M2 (x) CoO 3 (M2 being at least one selected from a group consisting of La, Pr, Sm and Nd; and x satisfying 0≦x<1).