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Structural Variants of Perovskite Oxides
Published in Gibin George, Sivasankara Rao Ede, Zhiping Luo, Fundamentals of Perovskite Oxides, 2020
Gibin George, Sivasankara Rao Ede, Zhiping Luo
Aurivillius phases are perovskite-layered structures with the general formulae (Bi2O2)(An−1BnO3n+1). Compared with RP and DJ phases, the interlayers of A′-site ions are replaced by Bi2O3 layers; therefore, the perovskite layers are sandwiched between the [Bi2O2]2+ layers. In an Aurivillius phase, A-site ions are usually large with a coordination number of 12, and B-site ion is a small ion with octahedral coordination. In Aurivillius-structured perovskites, the adjacent pseudo perovskite slabs are displaced by a distance (ap + bp)/2 along the z-axis, and the structure of the Bi2O2 layer is similar to that of fluorite. The ideal structure of Aurivillius perovskites for n = 1 − 5 is shown in Figure 4.8. The cations that can occupy A site are Na, K, Ca, Sr, Ba, etc. and B-site are Fe, Cr, Ti, Ga, Nb, V, Mo, W, etc. (Kendall et al. 1996).
Magnetic Behavior of Multicomponent Bismuth Niobates and Bismuth Titanates, with Pyrochlore and Layered Perovskite-Type Structures
Published in Natalia V. Chezhina, Dmitry A. Korolev, Electronic Structure of Materials, 2019
Irina V. Piir, Mariya S. Koroleva, Dmitry A. Korolev, Natalia V. Chezhina
In the Bi2O3−TiO2 system a Bi4Ti3O12 mixed oxide with layered perovskite structure related to the phases of Aurivillius is formed when n(Bi)/n(Ti) > 1.13 The family of Aurivillius phases includes bismuth titanates with the general formula (Bi2O2)2+ (Am−1BmO3m+1)2−, where m is the number of perovskite–like layers between (Bi2O2)2+ layers, A and B metal atoms in the I, II, III, and IV, V, VI oxidation states, respectively. Atoms A and B can occupy both types of the sites, and many Aurivillius phases elemental compositions can be expected. Possible compositions of Aurivillius phases are given in Table 5.1. The crystal structure of all Aurivillius phases consists of an alternation of perovskite-like layers (Am−1BmO3m+1)2− and bismuth-oxygen layers Bi2O22+. A-ions with large radii and rather low degrees of oxidation (Bi, Pb, Ba, Sr, Ca, K, Na, lanthanides) are located in the dodecahedral surrounding of oxygen atoms, and B-ions with small radii are in the highest oxidation degree and octahedral oxygen coordination. The value of m may vary in the range 1–5.
Removal of rhodamine B from aqueous solution using SrCoxBi4Ti4-xO15 aurivillius phase ceramics
Published in Inorganic and Nano-Metal Chemistry, 2020
Morteza Ziyaadini, Majid Ghashang
The Aurivillius phases with a general formula of Bi2An-1BnO3n+3 are known for some interesting features due to their high Curie temperature and low dielectric constant which are beneficial characteristics to be used widely as catalysts, ferroelectric and piezoelectric materials, in electronic devices and non-volatile random access memories.[1–6] Among several Aurivillius-like ceramics, SrBi4Ti4O15 has appropriate ferroelectric polarization and Curie temperature.[2–5] The ferroelectric, piezoelectric and some other characteristics of SrBi4Ti4O15 were investigated. Mamatha and Sarah synthesize the SrBi4Ti4O15 Aurivillius structure via a sol-gel method and reported their impedance and electrical conductivity.[7] The upconversion photoluminescent (UC) properties of Er3+ doped SrBi4Ti4O15 were investigated by Peng et-al.[8] Simoes et-al. showed that SrBi4Ti4O15 thin films deposited on Pt/Ti/SiO2/Si substrates have a typical butterfly loop that confirms the ferroelectric properties of the film.[9] The Co3+-modified SrBi4Ti4O15 exhibits reasonable piezoelectric properties when compared to their pure ones.[10] SrBi4Ti4O15 is usually prepared using solid-state, sol-gel, pulsed laser deposition (PLD), conventional sintering technique, hydrothermal reaction, and molten-salt methods.[2–13] These procedures suffer from non-homogeneous produced products that are not pure and need more purification.