Patent ID: 8801150

Claim:
A piezoelectric device, comprising the following on a substrate in the order listed below: a lower electrode, a piezoelectric film which contains a Pb containing perovskite oxide represented by a general expression (P) below, and an upper electrode, wherein: the piezoelectric film has a layer of pyrochlore oxide on the surface facing the lower electrode; and the average layer thickness of the pyrochlore oxide layer is not greater than 20 nm, and A a B b O 3 (P) where, A: at least one type of A-site element containing Pb as a major component, B: at least one type of B-site element selected from the group consisting of Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Sc, Co, Cu, In, Sn, Ga, Zn, Cd, Fe, and Ni, and O: an oxygen element, and a=1.0 and b=1.0 or the values of a and b may deviate from 1.0 within a range in which a perovskite structure can be formed.