BiFeO₃ synthesis by conventional solid-state reaction

Abstract

BiFeO3 is a multiferroic material with the perovskite structure which is promising for use in sensors and transducers. Single phase production of BiFeO3 remains a challenge, however. In this study, the optimal calcination temperature to obtain close to single phase powder was determined to be 750 °C. The sintering temperature of 775 °C was also found to obtain high density ceramics ( ≈ 95 % of theoretical density). It is shown that off-stoichiometry of bismuth oxide in precursors effects the content of secondary phase. Impedance spectroscopy indicates that the content of secondary phases has a large effect on the electrical conductivity BiFeO3 .

Exploring the BiFeO3-PbTiO3-SrTiO3 Ternary System to Obtain Good Piezoelectrical Properties at Low and High Temperatures

“…All binary and ternary ceramics produced in this work exhibit an average grain size of about 4-7 µm. An earlier study on BFO-PT ceramics reported a grain size of about 1 µm [1], while single-phase BFO sintered to a fully dense state could have a grain size of 10 µm [2]. The increase in the grain size in the ternary system with respect to the binary system might be due to a decrease in tetragonality upon the addition of ST.…”

“…For example, conventional ultrasonic echography measurements of the wall thickness of pipes and tanks offer advantages over other non-destructive testing methods, such as low cost, ease of operation, and the ability to conduct in operando measurements [1]. Piezoelectric sensors are already well established for this type of application but are limited to operating temperatures of up to 260 • C [2] due to most devices relying on the ubiquitous piezoelectric ceramic lead zirconate titanate or PZT. Therefore, considerable efforts are now aimed at developing materials that can satisfy the growing demand for piezoelectric elements with operating temperatures within the range of 350-600 • C.…”

“…The ceramics were prepared by a conventional powder sintering method. The objectives of this study were: (1) to obtain high-strength piezoceramics with a low electrical conductivity at room temperature and a suitable coercive field for complete polarization, (2) to study the softening effect of ST on BFO-PT ceramics and determine the position of the phase boundary, and (3) to study the temperature dependence of the piezoelectric and electrical properties for the most promising systems.…”

Molecular Orbital Calculation of Lead-Free Perovskite Compounds for Efficient Use of Alkaline and Alkaline Earth Metals

“…First, the covalency and ionicity of alkaline metals lithium (Li), Na, and K (designated as MA) were investigated based on For piezoelectric perovskites, alkaline and alkaline-earth metals are traditionally regarded as representative ionic species occupying the site of Pb or A [17]. Although there are more modern systems such as BNT [10][11][12][13] and BNT-based solid solutions [18], we focused on traditional systems, namely, BiFeO 3 [19] and GaFeO 3 [20], since our work was on the efficient use of ubiquitous alkaline and alkaline-earth metals. Both species of traditional systems are ionic; their formal ionic charges are 1+ and 2+, respectively.…”

Synthesis, Characterization, and Photocatalytic Activity of Ba-Doped BiFeO3 Thin Films

“…Among multiferroic materials, perovskite BiFeO 3 (BFO) is one of the few and best known room-temperature multiferroics, that has a distorted perovskite structure that belongs to rhombohedral R3c symmetry (with a = 3.958 and α = 89.30 • ), with a high ferroelectric Curie temperature (T C = 830 • C) and antiferromagnetic order (T N = 370 • C) [11][12][13]. The preparations of BiFeO 3 powder material were reported by different synthesis methods, as for example: solid-state reaction method [14], hydrothermal synthesis route [15], sol-gel process [16] combustion method [17], Pechini method [18], and microwave synthesis [19]. However, the preparation of BiFeO 3 is very difficult due to: (i) The kinetics of phase formation in the Bi 2 O 3 -Fe 2 O 3 system that leads to the formation of impurities along with the perovskite major phase [20] and thermal stability; (ii) valence fluctuation of iron (Fe 3+ /Fe 2+ transitions) which leads to the variation of oxygen stoichiometry and appearance of the oxygen vacancies as defects; (iii) Bi volatilization because bismuth oxide has a low melting point.…”