Enhanced spontaneous polarization in double perovskite Bi₂FeCrO₆ films

Abstract

We report the pulsed‐laser deposition of epitaxial double‐perovskite Bi2FeCrO6 (BFCO) films on the (001)‐, (110), and (111)‐oriented single‐crystal SrTiO3 substrates. All of the BFCO films with various orientations show the 1-0.166667emtrue/21-0.166667emtrue/21-0.166667emtrue/2 and 3-0.166667emtrue/23-0.166667emtrue/23-0.166667emtrue/2 superlattice‐diffraction peaks. The intensity ratios between the 1-0.166667emtrue/21-0.166667emtrue/21-0.166667emtrue/2‐superlattice and the main 111‐diffraction peak can be tailored by simply adjusting the laser repetition rate and substrate temperature, reaching up to 4.4%. However, both optical absorption spectra and magnetic measurements evidence that the strong superlattice peaks are not correlated with the B‐site Fe3+/Cr3+ cation ordering. Instead, the epitaxial (111)‐oriented Bi2FeCrO6 films show an enhanced remanent polarization of 92 μC/cm2 at 10 K, much larger than the predicted values by density‐functional theory calculations. Positive‐up‐negative‐down (PUND) measurements with a time interval of 10 μs further support these observations. Therefore, our experimental results reveal that the strong superlattice peaks may come from A‐ or B‐site cation shifts along the pseudo‐cubic [111] direction, which further enhance the ferroelectric polarization of the BFCO thin films.

Self-Powered Phase Transition Driven by Triboelectric Nanogenerator

“…The optical transmittance of BM-SCO is weak in the visible light region and significantly enhanced in the infrared region, while PV-SCO is nearly opaque in both the visible light and infrared regions. Figure b indicates the relationship between the photon energy ( hv ) and (α hv ) 2 plot obtained from the optical absorption spectra (Figure S4), where α is the optical absorption coefficient, which can estimate the direct bandgap of two phases . Accordingly, the direct bandgap of BM-SCO is approximately 2 eV, which causes the difference in optical transmittance from the visible light to the infrared region.…”

“…Figure 4b indicates the relationship between the photon energy (hv) and (αhv) 2 plot obtained from the optical absorption spectra (Figure S4), where α is the optical absorption coefficient, which can estimate the direct bandgap of two phases. 35 Accordingly, the direct bandgap of BM-SCO is approximately 2 eV, which causes the difference in optical transmittance from the visible light to the infrared region. The difference in the optical performance of the two phases creates an application in smart windows.…”

Laser Processing Methods for Perovskite Solar Cells and Modules

“…These films were reported to show enhanced spontaneous polarization. [ 66 ] Figure 9 clearly illustrates the interdependency between crystal orientation and the ferroelectric properties.…”

“…Epitaxially grown double perovskite Bi 2 FeCrO 6 films on the (001)-, (110)-, and (111)-oriented single-crystal SrTiO 3 substrates were prepared by PLD as reported by Meng et al These films were reported to show enhanced spontaneous polarization. [66] Figure 7. a) Device architecture of laminated perovskite solar cell/module.…”

“…d) Temperature-dependent remanent polarization of the BFCO films. Reproduced with permission [66]. Copyright 2019, The American Ceramic Society.…”