CRYSTAL ORIENTATION ANISOTROPY OF EPITAXIAL Pb(Mg1/3Nb2/3)O3-PbTiO3 THICK FILMS GROWN BY MOCVD

Abstract

ABSTRACT (100), (110), and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 PbTiO3 (PMN-PT) films with a thickness of 2–3 μm were grown on (100) c SrRuO3//(100)SrTiO3, (110) c SrRuO3//(110)SrTiO3, and (111) c SrRuO3//(111)SrTiO3 substrates, respectively, by pulsed-metalorganic chemical vapor deposition (MOCVD). Epitaxial films with different three crystal orientations were successfully grown on these substrates irrespective of PT content. Relative dielectric constant, ϵr, took the maximum at PT content around 0.40 for all orientations. Remanent polarization, P r, and coercive field, E c, increased with increasing PT content, and had a small peak at PT content around 0.45 and increased again. Longitudinal field-induced strain also showed the maximum against the PT content for all crystal orientations. However, PT content took maximum longitudinal field-induced strain was 0.40 for {100} orientation, while was 0.45 for {110} and {111} orientations. In addition, its absolute value of longitudinal field-induced strain was much smaller than reported ones for sintered bodies and single crystals. The large crystal anisotropy on electrical properties reported for the single crystal was hardly observed even in epitaxially grown films. This suggests the electrical properties were strongly influenced by the stress from the substrate.