Phase diagrams and electromechanical properties of polydomain epitaxial (1−x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃ thin films

Abstract Ferroelectric thin films usually exhibit polydomain structures, while current thermodynamics analysis on (1−x)Pb(Mg1/3Nb2/3)–xPbTiO3 [(1−x)PMN–xPT] thin films assumed films only possessing single domain. Thus we predict misfit strain–temperature phase diagrams and electromechanical properties of epitaxial (1−x)PMN–xPT thin films via thermodynamics analysis with polydomain structures taken into account. The results show that polydomain structures are more stable than single domain in most areas, consistent well with experimental observations. Phase diagram for 0.7PMN-0.3PT thin films obviously differs from those for 0.58PMN-0.42PT and 0.3PMN-0.7PT thin films. Excellent electromechanical properties are observed near the phase boundary between c and r 1/r 2 phases in 0.7PMN-0.3PT thin films.