Electric control of straight stripe conductive mixed-phase nanostructures in La-doped BiFeO3

Abstract

This study examines the atomic force microscope (AFM) tip-based electrical formation of tens of microns long stripe (and B100 nm wide) inorganic one-dimensional nanostructures based on the morphotropic phase boundary of La-doped BiFeO 3 epitaxial thin films. The substitution of Lanthanum into bismuth ferrite not only produces the formation of straight stripe mixedphase patterns but also improves the spatial continuity drastically by two orders of magnitude. We create, switch and erase stripe nanostructures in a reversible and deterministic way. We demonstrate that electrically formed areas with a nearly single variant alignment can be overwritten with different alignments repeatedly, which reflects the reversible and nonvolatile nature of the switching process. In addition, we explore the functionality of the created nanostructures by clarifying ferroelectric polarizations and observing the improvement of the electronic conduction at the phase boundary. Our findings provide new pathways to one-dimensional rewritable nanostructures and inspire researchers to conceive various multifunctional devices by combining the superb electromechanical property with their unique interfacial electronic conduction properties at nanoscale phase boundaries.

Structural and electronic transformation pathways in morphotropic BiFeO3

“…1(b,d). Based on earlier published reports223033, the polarization of the R-like phase is tilted away from the surface normal compared to the nearly vertical orientation in the T-like phase. Therefore, the structural transformation as observed (“event #1”) in Fig.…”

Structural, magnetic, and ferroelectric properties of T-like cobalt-doped BiFeO3 thin films

“…Doping of BFO in general offers attractive features that can alter the material's properties in technologically relevant ways, 17,24,25 particularly with respect to domain wall and phase boundary conductivity. 26,27 More specifically, the introduction of cobalt into the BFO structure has been predicted to induce discrete high and low spin states 28 and through this mechanism increase the magnitude of the weak magnetic moment. 29 It has also been shown that doping BFO nanoparticles with cobalt can have significant effects on the magnetic and magnetoelectric behavior.…”

Strain-gradient-induced magnetic anisotropy in straight-stripe mixed-phase bismuth ferrites: Insight into flexomagnetism

“…By performing a systematic angle-resolved piezoresponse force microscopy (PFM) study in BLFO thin films on LAO substrates, Kim et al argued that a slow-scan direction during PFM-based electrical poling determines the major elongation axis of MPBs and it is possible to create uniform long-and-straight stripes [16]. By virtue of the excellent MPB controllability of BLFO thin films, we have been able to survey a correlation between the MPB elongation axis and its in-plane AFM spin axis.…”