| abstract |
A piezoelectric element includes a first electrode formed on a substrate, a piezoelectric layer formed on the first electrode and composed of a complex oxide having a perovskite structure containing potassium (K), sodium (Na), niobium (Nb), and manganese (Mn), and a second electrode formed on the piezoelectric layer. The manganese includes divalent manganese (Mn 2+ ), trivalent manganese (Mn 3+ ), and tetravalent manganese (Mn 4+ ), a molar ratio of the divalent manganese to a sum of the trivalent manganese and the tetravalent manganese ((Mn 2+ /(Mn 3+ +Mn 4+ )) is 1 or more and 10 or less, and a molar ratio of the potassium to the sodium (K/Na) is 1.1 or less. |