Band Excitation Piezoresponse Force Microscopy of PbZrTiO3

<p>400 nm thick (001)-oriented PbZr_0.2Ti_0.8O₃/30 nm Ba_0.5Sr_0.5RuO₃/NdScO₃ epitaxial thin films were grown using pulsed laser deposition. The films have been the subject of prior studies (<em>9</em>, <em>15</em>, <em>22</em>). These films exist in a typical tetragonal ferroelectric phase. NdScO₃ imposes a large tensile strain that drives a strain-induced spinodal instability driving a hierarchical <em>c/a/c/a</em> and <em>a₁/a₂/a₁/a₂</em> domain structure (<em>29</em>). These domains have large variations in piezoresponse and switching mechanisms. Within the primary out-of-plane polarized <em>c/a/c/a,</em> there is a large vertical piezoresponse and classical ferroelectric switching mechanisms. Conversely, there is suppressed vertical piezoresponse in the <em>a₁/a₂/a₁/a₂</em> domains. Since this material is at an energetic degeneracy between the <em>c</em>/<em>a</em>/<em>c</em>/<em>a</em> and <em>a₁</em>/<em>a₂</em>/<em>a₁</em>/<em>a_2,</em>applying bipolar-triangular switching waveforms results in a two-step, three-state ferroelastic switching process. The films topography has a sawtooth-like structure with an amplitude of ~4 nm and a periodicity of ~900 nm because of the tetragonality and large difference in crystallographic orientation of domain variants. Furthermore, the highly asymmetric elastic modulus tensor results in elastic modulus variations by up to 23%. Further details regarding the structure, properties, and switching mechanisms of this material can be obtained in prior reports (<em>9</em>, <em>15</em>, <em>22</em>). The hierarchical PbZr_0.2Ti_0.8O₃ provides a model system to stress test Band-excitation piezoresponse force microscopy (BE-PFM) due to the highly variable piezoresponse, switching mechanisms, and elastic modulus. The dataset used is an original creation of the authors, has been the subject of prior reports, and publicly released under the open-source creative commons attribution 4.0 License (<em>30</em>).</p>