Orientation-dependent potential barriers in case of epitaxial Pt–BiFeO3–SrRuO3 capacitors

Abstract

The leakage current in epitaxial BiFeO 3 capacitors with bottom SrRuO 3 and top Pt electrodes, grown by pulsed laser deposition on SrTiO 3 ͑100͒, SrTiO 3 ͑110͒, and SrTiO 3 ͑111͒ substrates, is investigated by current-voltage ͑I-V͒ measurements in the 100-300 K temperature range. It is found that the leakage current is interface-limited and strongly dependent on the orientation of the substrate. The potential barriers at the electrode interfaces are estimated to about 0.6, 0.77, and 0.93 eV for the ͑100͒, ͑110͒, and ͑111͒ orientations, respectively.

Screening effects in ferroelectric resistive switching of BiFeO3 thin films

“…16 This result is consistent with earlier reports by Pintilie et al, showing that the height of the electronic barrier determines the current through a thick BiFeO 3 films when using macroscopic electrodes. 22 Also, in agreement with the n-doped character of the BifeO 3 layer (due to oxygen vacancies), the observed conduction corresponds to electrons injected from the top Cr-electrode.…”

“…20,21 Assuming small (and non-overlapping) depletion layers, this model has given experimental Schottky barrier height (SBH) values in the range of ϕ o = 0.2-0.9 eV for various ferroelectrics and orientations. [22][23][24] Classically, the "dead layer" (non-switchable interface layer) was assumed to be associated to defects in the film. But even in the case of an ideal, defect-free, ferroelectric layer, a "dead-layer" or series capacitance always exists due to imperfect screening.…”

Local conductivity and the role of vacancies around twin walls of (001)−BiFeO3 thin films

“…This has been reported to be the main conduction mechanism in some ferroelectric oxides, including BiFeO 3 [34] and PZT [19]. The field and temperature dependence of the PF currents are similar to those of the Richardson-Schottky (RS) emission, a third mechanism to be considered.…”

“…[31]), it can be inferred that the (001) atomic planes of the film are parallel to those of the substrate and buffer layer and, thus, that there is no out-of-plane tilt or buckled interface, as reported for some (001)-oriented rhombohedral perovskites [28,32,33]. This is important because the nature of the interfaces will largely influence the conduction properties of the films [34] We have performed DC transport measurements on a VEECO (now Bruker) Dimension V Conductive Atomic Force Microscope (CAFM) provided with a (Co-Cr coated Si) metallic tip. Electrically, the tip is connected to the ground of the microscope and a bias voltage is applied to the metallic sample holder, which is connected to the SrRuO 3 bottom electrode using silver paste on the side of the sample.…”

Tuning the atomic and domain structure of epitaxial films of multiferroicBiFeO3

“…23 However, the lack of a coherent interface can, in some cases, be advantageous since these films are less clamped and could better allow polarization rotation 7 or a lower leakage characteristics. 23,24 These differences are determined not only by the substrate miscut but also by the growth conditions. Here we show that it is possible to control not only the structure and the type of domains but also their orientation relative to the substrate, which is of crucial importance to understand the ferroelectric properties of the films.…”