Studies on the thermal stability of BiFeO3 and the phase diagram of Bi-Fe-O system

Meera, A.V.; Ganesan, Rajesh; Gnanasekaran, T.

doi:10.1016/j.jallcom.2019.03.205

Cited by 9 publications

(3 citation statements)

References 27 publications

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“…For instance, a handful of studies highlight the effect of annealing temperature on the final phase composition in this sol–gel setting, 47 , 49 , 50 generally indicating that BiFeO 3 has a rather narrow stability window that avoids impurity phase formation between 500 and 650 °C; this narrow stability is consistent with the results from computational work. 51 , 52 Additionally, it has been shown that a Bi/Fe > 1 ratio is helpful to avoid bismuth loss, but bismuth in excess higher than 10% may lead more frequently to Bi-rich secondary phases. 53 Although methods for synthesizing phase-pure BiFeO 3 are known, 54 , 55 understanding of the fundamental mechanisms governing the interplay between synthesis conditions and impurity formation remains limited.…”

Section: Background and Introductionmentioning

confidence: 99%

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Cruse,

Baibakova,

Abdelsamie

et al. 2023

Chem. Mater.

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We used data-driven methods to understand the formation of impurity phases in BiFeO 3 thin-film synthesis through the sol−gel technique. Using a high-quality dataset of 331 synthesis procedures and outcomes extracted manually from 177 scientific articles, we trained decision tree models that reinforce important experimental heuristics for the avoidance of phase impurities but ultimately show limited predictive capability. We find that several important synthesis features, identified by our model, are often not reported in the literature. To test our ability to correctly impute missing synthesis parameters, we attempted to reproduce nine syntheses from the literature with varying degrees of "missingness". We demonstrate how a text-mined dataset can be made useful by informing new controlled experiments and forming a better understanding for impurity phase formation in this complex oxide system.

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Section: Background and Introductionmentioning

confidence: 99%

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Cruse,

Baibakova,

Abdelsamie

et al. 2023

Chem. Mater.

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“…The stability of this phase is considered in several aspects, comprising thermal and structural stability as well as the reproducibility of magnetic and ferroelectric properties. In the study by [10], on the basis of thermogravimetric/differential thermal analysis, differential scanning calorimetry (TG/DTA, DSC), long-term equilibrations, and oxygen potential measurements methods, the authors came to the conclusion that BiFeO 3 is metastable at low temperatures and becomes stable only around 670 • C. At lower temperatures, BiFeO 3 co-exists with Bi 2 Fe 4 O 9 and Bi 25 FeO 39 . The thermal stability of BiFeO 3 is closely related to its structural stability-in the temperature range from room temperature to 960 • C, the phase undergoes three structural transitions from rhombohedral R3c to 650 • C, through orthorhombic Pbnm in the range 650-830 • C, to another type of Pbnm structure in the range 830-925 • C, and cubic from 925 • C to the melting point of about 960 • C. The detailed analysis shows that these structural transitions are driven by the change of the character of the 6s 2 lone electron pair of Bi 3+ ion from dominant (localized) at low temperatures to suppressed (delocalized) at high temperatures [11].…”

Section: Introductionmentioning

confidence: 99%

Rietveld Study of the Changes of Phase Composition, Crystal Structure, and Morphology of BiFeO3 by Partial Substitution of Bismuth with Rare-Earth Ions

et al. 2021

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BiFeO3 is an interesting material due to its multiferroic properties. It attracts attention due to its potential applications in spintronics and in microelectronics for data storage, among others. Single-phase bulk material from BiFeO3 is difficult to synthesize. The kinetics of perovskite phase formation most often leads to the presence of impurity phases. It has been shown that low levels of replacement of Bi with rare earth ions lead to stabilization of the perovskite phase. In the present work, Rietveld refinement of the crystal structure based on powder X-ray diffraction patterns was applied to study the influence of partial substitution of Bi by rare-earth (RE) elements with different ionic radii on structural and morphological properties of the ferrite phase. Substitution by large RE ions was found to preserve the rhombohedral symmetry of BiFeO3, whereas substitution by smaller RE ions led to the coexistence of two polymorphic perovskite phases with rhombohedral R3c and orthorhombic Pnma symmetries. The unit cell parameters as well as the interatomic distances and angles, not only around the A cation but also around the iron ions, were influenced by the substitution. The mean crystallite and particle size decreased with the decrease of ionic radius of substituting RE ion.

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According to the phase diagram, [24,25] Bi 2 O 3 (99.99%) and Fe 2 O 3 (99.9%) powders were mixed at the molar ratio of 4:1. The powder mixture was put into an agate ball mill with isopropanol as the medium and stirred for 12 h. The powder was afterward dried in a drying oven at 70 °C and then pressed for 30 min with a press die under a pressure of 40 MPa.

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confidence: 99%

Effect of Cooling Rate on the Crystalline Morphology of Bi₂O₃‐Fe₂O₃ Pseudo‐Binary System

Zhuang

Pan

Liu

et al. 2023

Physica Status Solidi (a)

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Herein, the crystallographic morphology of the 80%Bi2O3‐20%Fe2O3 pseudo‐binary system under different cooling rates (100, 6.3, 0.12 K s−1) is investigated using an optical microscopy system. The interfacial morphology evolution and interfacial kinetics in two dimensions during crystal growth are systematically studied. At the low cooling rate (ΔT < 10 K), blade‐like crystals appear slowly in the melt. In turn, the emergence of numerous irregularly shaped grains in the melt at the high cooling rate (ΔT > 100 K) indicates a rapid solidification process. Tetragonal crystals appear typically during melt solidification accompanied with triangular crystals simultaneously (15 K < ΔT < 35 K). The X‐ray diffraction and EDS data reveal that both kinds of polygonal crystals are attributed to Bi25FeO40. In addition, the crystal growth kinetics are presented as the dependence of the growth rate on the subcooling, and thus the growth mechanism of crystals is discussed. According to the results, Bi25FeO40 crystals grow through a two‐dimensional nucleation mechanism.

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Studies on the thermal stability of BiFeO3 and the phase diagram of Bi-Fe-O system

Cited by 9 publications

References 27 publications

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Rietveld Study of the Changes of Phase Composition, Crystal Structure, and Morphology of BiFeO3 by Partial Substitution of Bismuth with Rare-Earth Ions

Effect of Cooling Rate on the Crystalline Morphology of Bi₂O₃‐Fe₂O₃ Pseudo‐Binary System

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Studies on the thermal stability of BiFeO3 and the phase diagram of Bi-Fe-O system

Cited by 9 publications

References 27 publications

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO3

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO3

Rietveld Study of the Changes of Phase Composition, Crystal Structure, and Morphology of BiFeO3 by Partial Substitution of Bismuth with Rare-Earth Ions

Effect of Cooling Rate on the Crystalline Morphology of Bi2O3‐Fe2O3 Pseudo‐Binary System

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Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Text Mining the Literature to Inform Experiments and Rationalize Impurity Phase Formation for BiFeO₃

Effect of Cooling Rate on the Crystalline Morphology of Bi₂O₃‐Fe₂O₃ Pseudo‐Binary System