Phonon properties of nanosized bismuth layered ferroelectric material—Bi₂WO₆

Abstract

Nanosized Bi 2 WO 6 was synthesized by a mild hydrothermal crystallization process. This method allowed obtaining plate-like crystallites of very small thickness (down to 3 nm). The effect of particle size on the structure and properties of Bi 2 WO 6 was studied by X-ray diffraction (XRD), transmission electron microscopy, and Raman and infrared spectroscopies. It has been shown that the orthorhombic distortion decreases with decreasing particle size, but the structure of the smallest crystallites is still orthorhombic. Raman studies have also revealed a very strong intensity decrease for those modes that appear mainly for incident and scattered light polarized perpendicular to the layers. This behavior has been attributed to a decrease in the orthorhombic distortion and a plate-like shape of the nanocrystallites.

Nano-zinc oxide damages spatial cognition capability via over-enhanced long-term potentiation in hippocamus of Wistar rats

“…Many properties of nanoparticles, such as surface and interface effects, 1 quantum size effect, 2 photocatalytic properties, 3 and phonon properties, 4 have been investigated. In humans, environmental exposure to nano-ZnO has shown that it stayed in the stratum corneum and accumulated in skin folds and/or hair follicle roots of the skin.…”

Ferroelectric properties of highly a-oriented polycrystalline Bi2WO6 thin films grown on glass substrates

“…Since the single crystal BWO had the polar axis perpendicular to the c-axis, it inferred the large remnant polarization of the BWO1 film is due to the highly a-oriented crystal structure of the BWO1 film. 15,16 Figure 3 To analyze the difference in the switching time, we evaluated ferroelectric domain wall energies of the two BWO thin films by Landau, Lifshitz, and Kittel's (LLK) scaling law. In the LLK law, the scaling exponent γ is proportional to the domain wall energy.…”

“…Since BWO films have a polar axis perpendicular to the c-axis, the highly a-oriented BWO2 film has a domain wall energy that is lower than the BWO1 film. 15,16 It is suggested that the BWO2 film has the fast polarization switching characteristics resulting from the low domain wall energy of the BWO thin films.…”

“…13,14 In particular, layered perovskite thin films, such as SrBi 2 Ta 2 O 9 and Bi 2 WO 6 (BWO), are well-known, fatigue-free ferroelectric thin films (although they do have lower ferroelectric polarizations than PZT thin films). 15,16 Since layered perovskite thin films have an inversion symmetry along the c-axis, the highly a-oriented layered perovskite thin films can have ferroelectric polarizations that are significantly higher than those of the c-oriented layered perovskite thin films. 15 In this work, we fabricated highly a-oriented BWO thin films on Pt/Ta/glass substrates by pulsed laser deposition (PLD) by controlling the oxygen partial pressure.…”

Effect of carbon coating on the electrochemical properties of Bi2WO6 nanoparticles by PVP-assisted sonochemical method

“…The FT-IR spectra of P1, P2, and P3 are given in Fig. 5a [32]. The bands observed at 1381 cm -1 infer to the bending vibrations of N-O bands [33,34].…”