Composition and orientation dependence of electrical properties of epitaxial Pb(ZrxTi1−x)O3 thin films grown using metalorganic chemical vapor deposition

Abstract

The composition dependence and orientation anisotropy of the dielectric and ferroelectric properties of epitaxial Pb(ZrxTi1−x)O3 (PZT) thin films grown using metalorganic chemical vapor deposition were investigated. {100}-, {110}-, and {111}-oriented PZT films were ascertained to have been grown on (100)c, (110)c, and (111)cSrRuO3//SrTiO3 substrates, respectively. The relative dielectric constant reached a maximum near x=0.5, around the morphotropic phase boundary (MPB) composition, irrespective of film orientation, with the {111}-oriented film showing the largest value. Well-saturated hysteresis loops were observed for all films, and abrupt saturation of the remanent polarization (Pr) and coercive field (Ec) values were observed when the value of x was small, irrespective of film orientation. The Ec value reached a minimum around the composition for {110}- and {111}-oriented films but not for {100}-oriented ones. The saturated polarization (Psat) and Pr values for the {111}-oriented film reached a maximum around the MPB composition, while attaining a minimum for films with other orientations. The ratio of Pr to Psat decreased near the MPB composition regardless of film orientation. These results suggest that the electrical properties of epitaxial PZT thin films strongly depend on both of the composition and orientation of the films.