Polarization Rotation in Ferroelectric Tricolor PbTiO3/SrTiO3/PbZr0.2Ti0.8O3 Superlattices

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• 作者：Nathalie Lem茅e ; Ingrid C. Infante ; C茅cile Hubault ; Alexandre Boulle ; Nils Blanc ; Nathalie Boudet ; Val茅rie Demange ; Michael G. Karkut
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：September 16, 2015
• 年：2015
• 卷：7
• 期：36
• 页码：19906-19913
• 全文大小：452K
• ISSN：1944-8252

文摘

In ferroelectric thin films, controlling the orientation of the polarization is a key element to controlling their physical properties. We use laboratory and synchrotron X-ray diffraction to investigate ferroelectric bicolor PbTiO₃/PbZr_0.2Ti_0.8O₃ and tricolor PbTiO₃/SrTiO₃/PbZr_0.2Ti_0.8O₃ superlattices and to study the role of the SrTiO₃ layers on the domain structure. In the tricolor superlattices, we demonstrate the existence of 180掳 ferroelectric stripe nanodomains, induced by the depolarization field produced by the SrTiO₃ layers. Each ultrathin SrTiO₃ layer modifies the electrostatic boundary conditions between the ferroelectric layers compared to the corresponding bicolor structures, leading to the suppression of the a/c polydomain states. Combined with the electrostatic effect, the tensile strain induced by PbZr_0.2Ti_0.8O₃ in the PbTiO₃ layers leads to polarization rotation in the system as evidenced by grazing incidence X-ray measurements. This polarization rotation is associated with the monoclinic Mc phase as revealed by the splitting of the (HHL) and (H0L) reciprocal lattice points. This work demonstrates that the tricolor paraelectric/ferroelectric superlattices constitute a tunable system to investigate the concomitant effects of strains and depolarizing fields. Our studies provide a pathway to stabilize a monoclinic symmetry in ferroelectric layers, which is of particular interest for the enhancement of the piezoelectric properties.