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.

Statistical electric field and switching time distributions in PZT 1Nb2Sr ceramics: Crystal- and microstructure effects

“…Unique electromechanical and dielectric properties of PZT films around MPB are believed to be mostly determined by {111}-oriented domains. 40 An increasingly slanted form of the P-E loops for higher-Zr compositions was also observed by Jo et al 42 at the measuring frequency of 2 kHz where it was related with generally easier switching at higher Zr contents.…”

“…There are some discrepancies concerning the high-field saturated values of the spontaneous polarization P s and the coercive field E c in {111}-oriented films. From P-E-hysteresis loops at a frequency of 20 Hz and the maximum electric field strength of 25 kV/mm, strongly composition dependent P s and P r as well as the minimum value of E c at MPB are reported by Oikawa et al 40 On the other hand, P-E-hysteresis loops at the frequency of 1 Hz with the maximum electric field strength of 40 kV/mm reveal that the saturated value of P s is composition independent, while E c demonstrates monotonic decrease from the tetragonal towards the rhombohedral side as reported by Gerber et al 41 The P-E-hysteresis loops become thereby increasingly slanted that means a decreasing P r /P s -ratio and smearing of the switching process on the field scale. Generally, smaller anisotropy and smaller lattice distortion facilitate easier domain reversal, which results in smaller coercive field strength E c .…”

“…[38][39][40][41][42] As well as in the case of (bulk) sintered PZT ceramics, 43 dielectric constant and electrical coupling in thin PZT films exhibit maximum for compositions near the MPB between the tetragonal and rhombohedral phases. [38][39][40][41] Thereby epitaxially grown thin films (200-300 nm) of {001} orientation possess a minimum value of the spontaneous polarization P s at MPB 39 while the {111}-oriented films display maximum P s and the remnant polarization P r at MPB 40,41 thus revealing a great impact of texture on the ferroelectric properties. There are some discrepancies concerning the high-field saturated values of the spontaneous polarization P s and the coercive field E c in {111}-oriented films.…”

Composition-dependent polarization switching behaviors of (111)-preferred polycrystalline Pb(ZrxTi1−x)O3 thin films

“…With increase of x, the P-V hysteresis loops changed shape from a nearly square to a slanted one. 2,3 We measured ∆P(t) of the PZT thin films using pulse measurements, as described previously. 8 Fig.…”

Growth behavior of artificial hexagonal GdMnO3 thin films

“…Also, interestingly, even the original orthorhombic GdMnO 3 phases were found to have specific preferred orientations on substrates with in-plane hexagonal symmetries. This information might be useful for future studies since the physical properties of films tend to depend strongly on their orientations [15]. The electrical properties of these films are currently under investigation.…”