Quasi-two-dimensional ferroelectricity with multiple switchable polarization states in N-H coinjected perovskite manganites.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41032599.
- Also identified by DOI 10.1126/sciadv.adx3747 and PMC identifier 12487897.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Topotactic transformation such as hydrogenation serves as a powerful approach to engineering material functionality. However, challenged by direct imaging of light elements and clarifying their role, dual ion-based topotactic tranformation has been poorly explored so far. Here, we report on NH<sub>3</sub> plasma-induced ferrodistortive phase transition in N<i><sub>x</sub></i>H<i><sub>y</sub></i>(La,Sr)MnO<sub>3-δ</sub> films (0 < <i>x</i> < 0.2, 0.5 < <i>y</i> < 1.0, and δ ≈ 0.125, 0.25, and 0.5), where the injected H and N are resolved to enhance the polar order along with antisite defects by atomic-resolution electron microscopy. Besides unveiling the mediation of structural modulation and N-H competition by oxygen-vacancy ordering degree, our piezoresponse force microscopy unravels a unique quasi-two-dimensional (q2D) ferroelectricity in fourfold modulated brownmillerite phase (δ ≈ 0.25), which offers a series of switchable polarization states by an applied electric field. Unlike all-known ferroelectrics, the q2D ferroelectrics establishes a promising material platform for design of future electronic devices such as multistate information storage.