Characteristic Comparison of Epitaxial PZT and PMN-PT Films Grown On (100)cSrRuO3//(100)SrTiO3 Substrates By Metalorganic Chemical Vapor Deposition

Epitaxial Pb(Zr_1-xTi_x)O₃ [PZT] and (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ [PMN-PT] films, above 2 mum in thickness, were grown on (100)_cSrRuO₃//(100)SrTiO₃ substrates by metalorganic chemical vapor deposition (MOCVD). PbTiO₃ content (x) dependencies of the crystal structure and piezoelectric properties were systematically investigated for these films. The longitudinal electric-field-induced strain Deltax₃₃ and transverse piezoelectric coefficient e_31,f for PZT films were also maximum at the almost center mixed phase region, on the other hand, that for PMN-PT films were maximum at larger x edge of rhombohedral (pseudocubic) region. Almost the same order of Deltax₃₃ was observed under applied electric fields up to 100 kV/cm, while larger e_31,f was observed in PMN-PT films compared with the case of PZT films. e_31,f coefficients of ~-8.9 C/m² and ~-11.0 C/m² were calculated for the PZT film with x=0.46 and for the PMN-PT film with x=0.39, respectively.