Patent ID: 7399067

Claim:
A piezoelectric thin film of perovskite crystals represented by a general formula Pb (1-x) La x (Zr y Ti 1-y )O 3 (where 0≦x <1, 0.05≦y≦1), wherein a film thickness of the piezoelectric thin film is 1000 nm or more and 4000 nm or less, the surface of the piezoelectric thin film includes crystal grains respectively having an equivalent circle diameter of 200 nm or more, and crystal grains respectively having an equivalent circle diameter of 40 nm or less, and the number of the crystal grains observed in the surface of the piezoelectric thin film and respectively having the equivalent circle diameter of 40 nm or less is 5% or more with respect to the total number of the crystal grains observed in the surface of the piezoelectric thin film.