Papers by Keyword: BaBi₄Ti₄O₁₅

Abstract: Aurivillius phase ferroelectrics Ba(Bi_1−xLa_x)₄Ti₄O₁₅(x=0-0.05) (BBiL_xT) was synthesized by a modified high-temperature solid-phase route.The structure, the dielectric, the ferroelectric and the aging properties were investigated systematically. With the La³⁺ doping, the room temperature relative permittivity of the samples is increased, and dielectric loss is decreased. For the BBiL_xT phase, only a weak variation with respect to the F2mm space group can be suggested from single crystal X-ray diffraction. The microstructure confirms the samples have a well-proportioned grain size and a higher density. The substitution also results in a marked improvement in the remnant polarization. The doping of La³⁺ in BBiLxT ceramics increased the room temperature relative permittivity aging properties.

Abstract: MBi4Ti4O15 (M=Ba,Ca) thick films were prepared by screen printing and firing using Pt bottom electrodes and ZrO2 substrates. Screen-printable pastes were prepared by kneading the MBi4Ti4O15 powder in a three-roll mill with an organic vehicle. The microstructures and electric properties of the thick films were examined in comparison with bulk ceramics. The remanent polarization of 6.2 9C/cm2 and coercive field of 130kV/cm were obtained for the CaBi4Ti4O15 thick film fired at 1130OC. The Curie points of MBi4Ti4O15 (M=Ba,Ca) thick films from dielectric peaks were 450OC and 790 OC for M=Ba and M= Ca.

Abstract: BaBi4Ti4O15 ceramics was prepared by molten salt synthesis method (MSS) and conventional solid phase process (CS). The phase of reaction products and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the evident anisotropic flake structure of BaBi4Ti4O15 powder prepared by MSS was obtained at 850°C and the level of anisotropy of BaBi4Ti4O15 powder decreased with increasing temperature. After calcined at 950°C, sintering in the range of 1100~1170°C, the sintering temperature and the maximum permittivity of BaBi4Ti4O15 ceramics prepared by MSS at same frequency was lower than those prepared by CS. Additionally, the apparent degree of orientation was obtained and the lotgering factor (f) calculated according to the XRD results showed a value of 0.63.

Abstract: The preparation and the microstructure of BaBi4Ti4O15 (BBT) thin films were reported in the paper. BBT thin films were fabricated on silicon substrate using a modified Sol-Gel technique. A key issue of Sol-Gel processing is the chemical reaction and mechanism of precursor solution, which governs the crystallization and characteristics of the final oxide layer. Ethanolamine is an effective complexation reagent of Bi3+, which could moderate the acidity of precursor. When pH value is about 3.5, the stable and uniform BBT precursor solution could be obtained. The Bi-layered perovskite structure of BBT forms at 750°C. The morphology of the grains in BBT thin films is spheroidal and the grain size is about 120nm.