Self-assembled nanoscale capacitor cells based on ultrathin BiFeO3 films

Abstract

Ultrathin multiferroic BiFeO3 (BFO) films with self-assembled surface nano-islands on La0.67Sr0.33MnO3/(100) SrTiO3 substrates are fabricated by a one-step pulsed laser deposition process using the Bi-rich BFO target. It is revealed that these surface nano-islands mainly consist of conductive Bi2O3 outgrowths, which serve as top electrodes for the nanoscale BFO capacitor cells with lateral size of 10–30 nm. The ferroelectric BFO layer underneath these Bi2O3 nanoislands prefers certain complex domain structure with vertical and antiparallel polarization components (the so-called “anti-domain structure”) and reduced domain switching fields. Moreover, these nanoscale capacitor cells exhibit the resistive switching IV behavior, offering opportunities for application in ultrahigh density non-volatile memories.

Surface Modification and Enhancement of Ferromagnetism in BiFeO3 Nanofilms Deposited on HOPG

“…In the work of Jiahua Zhu et al [ 21 ] it was shown that the magnetic field plays a decisive role in limiting the process of interfacial relaxation and thereby enhances the capacitance of the electrode, using an external magnetic field can dramatically increase the capacitance without replacing the material and structural modification. The interest in BFO films is significant in comparison to bulk materials because of its spontaneous mechanisms of switching and energy conservation [ 22 ]. There are many techniques for producing BFO films.…”

Controllable Photovoltaic Effect of Microarray Derived from Epitaxial Tetragonal BiFeO3 Films

“…where W top and W bottom are the work functions of the top electrode (Ti or Cr) and bottom electrode (LSMO), respectively, q is the positive elementary charge, and d is the thickness of the T-BFO film. Taking typical parameters W Ti = 4.33 eV, W Cr = 4.50 eV, W LSMO = 4.96 eV, 33,34 and q = 1.6 × 10 −19 C, d = 40 nm into eq 2, we obtain the electric field E in ≈ 1.6 × 10 7 V/m for the Au/Ti/T-BFO/LSMO and E in ≈ 1.2 × 10 7 V/m for the Au/Cr/T-BFO/LSMO. For both kinds of devices, the potential on the top interface is higher than that of the bottom, so the E in points downward.…”

Ordered multiferroic CoFe2O4–Pb(Zr0.52Ti0.48)O3coaxial nanotube arrays with enhanced magnetoelectric coupling

“…Theoretically, it should produce an overall built-in voltage of 0.38 eV, which breaks the equivalence of two polarization states and provides a strong tendency to align the domains to a preferred orientation. 8,47,48 Additionally, the surface charges stored at the interface between PZT and Pt electrode may contribute to the observed asymmetric polarization states. 49 In the PZT NTs, the PFM amplitude coercive voltage is around 4 V. However, in the CFO-PZT coaxial NTs, the corresponding coercive voltage increased to 5 V. The internal stress on the interface between the CFO and PZT layers, making it harder for the switching of ferroelectric domains, could result in an increased coercive voltage and the smaller PFM amplitude.…”