Disclosed are a piezoelectric element, which has a high withstand voltage
and a longer durability life, a manufacturing method of the piezoelectric
element, a liquid-jet head, a manufacturing method of the liquid-jet
head, and a liquid-jet apparatus. The manufacturing method of a
piezoelectric element includes the steps of: forming a piezoelectric
layer by forming, on the lower electrode, a piezoelectric precursor film
in which Pb, Zr and Ti are contained and the composition ratio of Pb, Zr
and Ti becomes Pb/(Zr+Ti)=1.0 to 1.3 after the piezoelectric precursor
film has been baked, and to which at least any one dopant selected from
the group consisting of manganese, nickel and strontium is doped, and by
then baking the piezoelectric. precursor film for half an hour to three
hours at 650 to 750.degree. C.; and forming an upper electrode on the
piezoelectric layer.