Robust In‐Plane Ferroelectricity in Ultrathin Epitaxial Aurivillius Films. Issue 14 (29th May 2020)

• Record Type: Journal Article
• Authors: Gradauskaite, Elzbieta; Campanini, Marco; Biswas, Banani; Schneider, Christof W.; Fiebig, Manfred; Rossell, Marta D.; Trassin, Morgan
• Is Part Of: Advanced materials interfaces. Volume 7:Issue 14(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-29
• Subjects: charged domain walls -- fatigue‐free ferroelectrics -- layered ferroelectric thin films -- uniaxial in‐plane polarization; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202000202
• Languages: English
• ISSNs: 2196-7350

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 Bi5 FeTi3 O15 thin films is demonstrated. The achievement of twin‐free films with sub‐unit‐cell thickness precision on a lattice‐matching NdGaO3 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. Abstract : Epitaxial single‐crystalline thin films of Aurivillius compound Bi5 FeTi3 O15 are grown on a lattice‐matching orthorhombic substrate. Layer‐by‐layer growth is demonstrated, permitting in situ control of thickness with sub‐unit‐cell accuracy. The achievement of twin‐free films significantly enhances their fatigue‐free, uniaxial ferroelectric properties. In the ultrathin regime, the films exhibit an arrangement of in‐plane ferroelectric domains with nominally charged domain walls.