Robust In‐Plane Ferroelectricity in Ultrathin Epitaxial Aurivillius Films
Elzbieta Gradauskaite, Marco Campanini, Banani Biswas, C. Schneider, M. Fiebig, Marta D. Rossell, Morgan Trassin
Abstract
Abstract Layered ferroelectrics, often referred to as natural superlattices, exhibit functionalities beyond those of the classical ferroelectric perovskite compounds due to their highly anisotropic structure. Unfortunately, the layered architecture has been impeding their growth as single crystalline thin films, and thus their integration into oxide‐electronic devices. Here, fatigue‐free ferroelectric switching in epitaxial Bi 5 FeTi 3 O 15 thin films is demonstrated. The achievement of twin‐free films with sub‐unit‐cell thickness precision on a lattice‐matching NdGaO 3 orthorhombic substrate significantly enhances their uniaxial ferroelectric properties. In the ultrathin regime, such films exhibit in‐plane polarization with a periodic arrangement of ferroelectric domains, which, with uniaxial ferroelectric anisotropy, results in nominally charged domain walls. The uniaxial in‐plane ferroelectricity and remarkable endurance after 10 10 switching cycles of Aurivillius thin films breaks new ground for alternative device paradigms that are less susceptible to limitations arising from the depolarizing‐field effects in the ultrathin regime.