Misfit strain phase diagrams of epitaxial PMN–PT films

Misfit strain–temperature phase diagrams of three compositions of (001) pseudocubic (1 − x)·Pb (Mgl/3Nb2/3)O3 − x·PbTiO3 (PMN–PT) thin films are computed using a phenomenological model. Two (x = 0.30, 0.42) are located near the morphotropic phase boundary (MPB) of bulk PMN–PT at room temperature (RT) and one (x = 0.70) is located far from the MPB. The results show that it is possible to stabilize an adaptive monoclinic phase over a wide range of misfit strains. At RT, the stability region of this phase is much larger for PMN–PT compared to barium strontium titanate and lead zirconate titanate films.