James LeBeau1
Massachusetts Institute of Technology1
James LeBeau1
Massachusetts Institute of Technology1
Although antiferroelectric materials have been studied for decades, they have gained renewed interest for potential applications in energy storage, actuation, and non-volatile memory. This is enabled by the polar behavior of AFEs, where the antiparallel alternation can be switched to lie in the same direction with a sufficiently strong electric field — i.e. an AFE to ferroelectric transition. Moreover, thin film growth of antiferroelectrics, including PbZrO3 (PZO) and Pb<sub>2</sub>MgWO<sub>6 </sub>(PMW), has been pursued to modify the properties of this transition and offers many new tantalizing opportunities to engineer the behavior of these materials. To further gain insights, direct investigations of the transformation mechanisms responsible will be key.<br/><br/>In this talk, we will highlight our results from ex and in situ aberration-corrected scanning transmission electron microscopy (STEM) studies of PZO and PMW thin films. In particular, we will focus on insights into the AFE-FE phase transformations during biasing of thin film PbZrO3. We will discuss the details of polarization switching and the evolution of domain structure, shedding light on the underlying mechanisms and defects governing the behavior. The role of strain, measured with cepstral analysis, and thin film growth orientation will also be explored to determine their impacts on the antiferroelectric/ferroelectric transition.<br/><br/>We will also highlight results from multislice electron ptychography to characterize chemical order and disorder in PMW, specifically at antiphase boundaries. By characterizing and mapping these boundaries, we gain a deeper understanding of their influence on local polarization and implications for polarization switching. Overall, STEM analysis provides critical insights into the defect/structure relationships and the impact of intrinsic and extrinsic factors on the behavior of antiferroelectric materials.