  The structural evolution of a polydomain ferroelectric Pb(Zr0.2Ti0.8)O3 film
was studied by temperature dependent X-ray diffraction. Two critical
temperatures were evidenced: T*=740K, corresponding to a change in the domain
structure (a/c/a/c to a1/a2/a1/a2), and Tc_film = 825K where the film undergoes
a ferroelectricparaelectric phase transition. The films remains tetragonal on
the whole range of temperature investigated. The evolutions of the domain
structure and lattice parameters were found to be in very good agreement with
the calculated domain stability map and theoretical temperature-misfit strain
phase diagram respectively.
