Manipulating the Ferroelectric Domain States and Structural Distortion in Epitaxial BiFeO Ultrathin Films via Bi Nonstoichiometry.

Exploring and manipulating domain configurations in ferroelectric thin films are of critical importance for the design and fabrication of ferroelectric heterostructures with a novel functional performance. In this study, BiFeO (BFO) ultrathin films with various Bi/Fe ratios from excess Bi to deficient Bi have been grown on (LaSr)MnO (LSMO)-covered SrTiO substrates by a laser molecular beam epitaxy system. Atomic force microscopy and piezoresponse force microscopy measurements show that both the surface morphology and ferroelectric polarization of the films are relevant to Bi nonstoichiometry.

Controllable growth of ultrathin BiFeO3 from finger-like nanostripes to atomically flat films.

BiFeO3 (BFO) ultrathin films with nominal thicknesses from 2 to 12 nm were grown with a SrRuO3 (SRO) buffer layer on TiO2-terminated (001) SrTiO3 (STO) substrates using pulsed laser deposition. The surface morphologies and domain configurations of the thin films were investigated using atomic force microscopy and piezoelectric force microscopy. Periodical one-dimensional finger-like nanostripes of BFO on the SRO covered STO substrates were observed.