Patent ID: 7732997

Claim:
A piezoelectric element, comprising: at least a substrate, a piezoelectric film and an electrode disposed between the substrate and the piezoelectric film, wherein the electrode includes an electroconductive oxide and an electroconductive metal, the electroconductive oxide is contained more than the electroconductive metal on the substrate side in the electrode, the electroconductive metal is contained more than the electroconductive oxide on the piezoelectric film side in the electrode, the electrode includes an electroconductive oxide layer situated on the substrate side, an electroconductive metal layer including the electroconductive metal situated on the piezoelectric film side and a mixture layer provided between the electroconductive oxide layer and the electroconductive metal layer and having the electroconductive oxide and the electroconductive metal mixed therein, and the piezoelectric element comprises a graded composition structure in which a ratio of the electroconductive oxide in the mixture layer is reduced gradually from an interface between the mixture layer and the electroconductive oxide layer to an interface between the mixture layer and the electroconductive metal layer.