Orientation and film thickness dependencies of (100)- and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 films grown by metal organic chemical vapor deposition

Abstract(100)- and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 films with 500 and 1300 nm in thickness were grown by metal organic chemical vapor deposition. Remained strain was almost relaxed because the crystal structure of the films was almost the same as that of bulk Pb(Mg1/3Nb2/3)O3. Relative dielectric constant showed the maximum value against the temperature that depended on the measurement frequency. Maximum relative dielectric constant, εr(max.), and the temperature showing εr(max.), T(max.), decreased and increased with the frequency, respectively, are in good agreement with reported data for the bulk. εr(max.) and T(max.), respectively increased and decreased with the film thickness and (111)-oriented films showed larger value than that of the (100)-oriented one. Ferroelectricity was observed for all films up to 297 K and monotonously decreased with increasing temperature. Saturation polarization value increased with the film thickness and (111)-oriented films showed larger value than (100)-oriented ones. On the other hand, the coercive field decreased with increasing film thickness, but was almost independent with the film orientation