[Abstract]

Visualizing the oxygen vacancy distributions is highly desirable for understanding the atomistic oxygen diffusion mechanisms in perovskites. In particular, the direct observation of the one-dimensional oxygen vacancy channels has not yet been achieved in perovskites with dual ion (i.e., cation and anion) ordering. Here, we perform atomic-resolution imaging of the one-dimensional oxygen vacancy channels and their structural dynamics in a NdBaCo2O5.5 double perovskite oxide. An in situ heating transmission electron microscopy investigation reveals the disordering of oxygen vacancy channels by local rearrangement of oxygen vacancies at the specific temperature. A density functional theory calculation suggests that the possible pathway of oxygen vacancy migration is a multistep route via Co–O and Nd–Ov (oxygen vacancy) sites. These findings could provide robust guidance for understanding the static and dynamic behaviors of oxygen vacancies in perovskite oxides.
 

DOI: doi.org/10.1021/acs.nanolett.0c03516

LINK: https://pubs.acs.org/doi/10.1021/acs.nanolett.0c03516