| abstract |
The piezoelectric element has a substrate, a lower electrode layer, a piezoelectric layer, and an upper electrode layer. The lower electrode layer is fixed to the substrate, and the piezoelectric layer is formed on the lower electrode layer. The upper electrode layer is formed on the piezoelectric layer. The lower electrode layer contains pores, and the thermal expansion coefficient of the lower electrode layer is larger than the thermal expansion coefficient of the piezoelectric layer. |