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arXiv · 0704.2401

Suppressed dependence of polarization on epitaxial strain in highly polar ferroelectrics

Ho Nyung Lee·Serge M. Nakhmanson·Matthew F. Chisholm·Hans M. Christen·Karin M. Rabe·David Vanderbilt
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Abstract

A combined experimental and computational investigation of coupling between polarization and epitaxial strain in highly polar ferroelectric PbZr_0.2Ti_0.8O_3 (PZT) thin films is reported. A comparison of the properties of relaxed (tetragonality c/a = 1.05) and highly-strained (c/a = 1.09) epitaxial films shows that polarization, while being amongst the highest reported for PZT or PbTiO_3 in either film or bulk forms (P_r = 82 microC/cm^2), is almost independent of the epitaxial strain. We attribute this behavior to a suppressed sensitivity of the A-site cations to epitaxial strain in these Pb-based perovskites, where the ferroelectric displacements are already 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 displacements can lead to substantial polarization increases.

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Ho Nyung Lee, Serge M. Nakhmanson, Matthew F. Chisholm, Hans M. Christen, Karin M. Rabe, David Vanderbilt. 2007-04-18. Suppressed dependence of polarization on epitaxial strain in highly polar ferroelectrics. https://doi.org/10.1103/physrevlett.98.217602

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