A combined experimental and computational investigation of coupling betweenpolarization and epitaxial strain in highly polar ferroelectricPbZr_0.2Ti_0.8O_3 (PZT) thin films is reported. A comparison of the propertiesof relaxed (tetragonality c/a = 1.05) and highly-strained (c/a = 1.09)epitaxial films shows that polarization, while being amongst the highestreported for PZT or PbTiO_3 in either film or bulk forms (P_r = 82microC/cm^2), is almost independent of the epitaxial strain. We attribute thisbehavior to a suppressed sensitivity of the A-site cations to epitaxial strainin these Pb-based perovskites, where the ferroelectric displacements arealready large, contrary to the case of less polar perovskites, such as BaTiO_3.In the latter case, the A-site cation (Ba) and equatorial oxygen displacementscan lead to substantial polarization increases.
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机译：报道了在高极性铁电体PbZr_0.2Ti_0.8O_3（PZT）薄膜中极化与外延应变耦合的实验与计算研究。比较弛豫（四边形c / a = 1.05）和高应变（c / a = 1.09）外延薄膜的性能，可以看出极化，尽管是薄膜或整体形式的PZT或PbTiO_3的最高记录之一（P_r = 82microC / cm ^ 2），几乎与外延应变无关。我们将这种现象归因于在这些基于Pb的钙钛矿中，A-位阳离子对外延应变的敏感性降低，而铁电位移已经很大，这与极性较小的钙钛矿如BaTiO_3的情况相反。阳离子（Ba）和赤道氧置换可能导致极化显着增加。
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