Unconventional ferroelectricity exhibited by hafnia-based thin films—robust at nanoscale sizes—presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La_0.67Sr_0.33MnO₃/Hf_0.5Zr_0.5O₂ capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry.

基于氧化ha的薄膜表现出的非常规铁电性（纳米级尺寸很强）为纳米电子学提供了巨大的机遇。但是，偏振切换的确切性质仍存在争议。我们研究了La _0.67 Sr _0.33 MnO ₃ / Hf _0.5 Zr _0.5 O ₂电容器与各种顶部电极连接，同时使用原子分辨率显微镜通过直接氧成像以及同步加速器纳米束衍射进行原位电偏压。当顶部电极具有氧反应性时，我们观察到可逆的氧空位迁移，其中电极作为氧的源和汇，而介电层则在毫秒时间尺度上充当快速导管。在无反应的顶部电极和较长时间尺度（秒）的情况下，介电层还充当氧源和氧沉。我们的结果表明，基于氧化f的薄膜中的铁电与氧气伏安法毫无疑问地交织在一起。