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Magnetic and Electrical Properties
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
One of the most studied examples of Type I multiferroics is BiFeO3, bismuth ferrite. The interest in this compound was sparked by the publication of a paper in Science in 2003, reporting the results from Ramamoorthy Ramesh’s group at the University of Maryland. The measurements showed that thin films of BiFeO3 had a large remanent polarisation. Bismuth ferrite has a Néel temperature of 643 K and a ferroelectric transition temperature of 1100 K, so it is multiferroic at room temperature. It adopts a perovskite structure with Bi−O and Fe−O layers. The spins on the Fe3+ ions are coupled antiferromagnetically. The ferroelectric effect is due to the alignment of the lone pairs of the Bi3+ ions, giving a cooperative offset arrangement.
Novel Applications of Multiferroic Heterostructures
Published in Alexander V. Vakhrushev, Omari V. Mukbaniani, Heru Susanto, Chemical Technology and Informatics in Chemistry with Applications, 2019
Ann Rose Abraham, Sabu Thomas, Nandakumar Kalarikkal
The ferromagnetic Ni cores are exchange coupled to the multiferroic BFO shell. The combined ferroelectric and antiferromagnetic functionalities of bismuth ferrite were utilized and an exchange bias effect was observed in the system. The scanning electron microscope (SEM) and transmission electron microscopy (TEM) images of Ni–BFO core–shell nanotubes are shown in Figure 6.4. The magnetic, ferroelectric properties and the magnetic reversal mechanism of the ferromagnetic–multiferroic core–shell nanostructures were studied. The rough core–shell interfaces are observed to reduce the exchange bias effect of the samples. Thus, ferromagnetic/ferroelectric two-phase, one-dimensional nanomaterials that allow electric field control of magnetization or magnetic field control of polarization is realized.
Novel Inorganic and Metal Nanoparticles Prepared by Inverse Microemulsion
Published in Victor M. Starov, Nanoscience, 2010
Perovskite BiFeO3 is a ferroelectric (Tc: 1103 K) as well as an antiferromagnetic (TN: 643 K) material [300]. Magnetoelectric materials, such as BiFeO3, have the potential for applications in magnetic as well as in ferroelectric devices. It exhibits weak magnetism at room temperature. The structure and properties of the bulk and single-crystal BiFeO3 have been extensively studied [301]. It has been shown to possess a rhombohedrally distorted perovskite structure at room temperature. A finite size effect study of bismuth ferrite has been carried out by different authors [302]. They showed that the particle size of bismuth ferrite is one of the controlling factors in its properties like magnetic ferroelectric properties. So far, bismuth ferrite powders have been prepared by the solid-state method and the solution chemistry method. In the solid-state method Bi2O3 and Fe2O3 are reacted and calcined at about 825°C followed by leaching of the unwanted phases with HNO3 [302]. In the case of the solution chemistry route, bismuth hydroxide and ferric hydroxide are precipitated simultaneously [303] by ammonia. The precipitate was then calcined at 650–800°C to get the phase pure BiFeO3. However, the particle size of the powder is in the micron range. Another approach of solution chemistry route of preparing bismuth ferrite nanopowder was from bismuth nitrate and iron nitrate, and tartaric acid was used as a chelating agent [304].
Au5+ ion implantation induced structural phase transitions probed through structural, microstructural and phonon properties in BiFeO3 ceramics, using synergistic ion beam energy
Published in Radiation Effects and Defects in Solids, 2018
Multiferroic materials having simultaneous presence of at least two or more of the ferromagnetic, ferroelectric and/or ferroelastic ordering have attracted a good attention in the last few years (1–7) due to their potential applications for magneto electric devices (8). Among all the multiferroic materials, Bismuth ferrite (BiFeO3/BFO) is a unique material having both anti-ferromagnetic and ferroelectric phase transition temperatures well above the room temperature. The BFO ceramics are very useful material for many potential applications such as photo-catalytic activity, microwave absorption and gas-sensing properties (9–11). BFO is a room temperature multiferroic with both ferroelectric Curie temperature (TC) ≈ 1103 K and magnetic Neel temperature (TN) ≈ 643 K (12–13) being above room temperature. In BFO, the ferroelectricity arises due to the stereo-chemical activity of 6S2 lone pair electrons of Bi3+, while the indirect magnetic exchange interaction between Fe3+ ions through O2− causes G-type anti-ferromagnetic ordering (14).
Elastic and attenuation behavior of the Bi1-x Re x FeO3 (x = 0 & 0.1; Re = La, Pr, Nd & Sm) multiferroic system
Published in Phase Transitions, 2021
Elle Sagar, K. Vijaya Kumar, P. Venugopal Reddy
The bismuth ferrite-based multiferroic materials with the compositional formula, Bi0.9Re0.1FeO3 (x = 0 & 0.1; Re = La, Pr, Nd and Sm) were prepared by the solid state reaction technique. In this method, highly pure (about 99.99%) Bi2O3, Fe2O3 and rare earth oxides were taken in the stoichiometry ratio and were ground for 12 h in an agate mortar. After grinding, the powders were calcined at 750°C for 3 h. Subsequently, the powders were leached with HNO3 to washout the impurity phases which might have been formed during the calcination process. After pelletizing the powders, the samples were sintered at 800°C for 3 h.
Investigation on photocatalytic degradation of crystal violet dye using bismuth ferrite nanoparticles
Published in Journal of Dispersion Science and Technology, 2021
Shahnaz Kossar, I. B. Shameem Banu, Noor Aman, R. Amiruddin
Bismuth ferrite materials were synthesized by a simple and versatile auto-combustion method.[19] Bismuth nitrate pentahydrate [Bi (NO3)3. 5H2O, ≥99.0%], iron (III) nitrate nonahydrate [Fe (NO3)3. 9H2O, ≥ 99.0%], gadolinium (III) nitrate heaxahydrate [Gd (NO3)3. 6H2O, ≥99.9%] and citric acid [C6H8O7, ≥ 99.0%] were used as precursor materials. For the preparation of Gd doped BiFeO3, the doping concentration of gadolinium (III) nitrate heaxahydrate was varied as 2 wt%, 5 wt%, and 10 wt%. At first 0.015 M of bismuth nitrate pentahydrate was dissolved in 20 ml of distilled water and 10 ml of diluted nitric acid and stirred continuously. For the preparation of Gd doped BiFeO3, the doping concentration of Gd was varied as 2 wt%, 5 wt%, and 10 wt%. A sufficient amount of gadolinium nitrate hexahydrate was added to the prepared solution. 0.015 M of ferric nitrate nonahydrate was poured dropwise to the mixed solution and stirred for 1 h at room temperature. 0.015 M of citric acid was added as a chelating agent and constantly stirred for 3 h. The obtained transparent solution is subjected to heat treatment of 90 °C until brownish fumes were observed. The obtained precipitates were grinded and calcined at 650 °C for 3 h. The structural studies of the prepared BFO samples were carried out by X-ray diffraction (XRD) technique (Bruker D8 Diffractometer with Cu Kα (λ = 1.5406 A˚). The surface morphological investigation was carried out by field emission scanning electron microscope (FESEM, FEI Quanta 200 F). The optical properties were performed by UV-Vis spectroscopy (Shimadzu UV-2600). The vibrational modes were performed by Fourier Transform Infrared spectroscopy (JASCO 6300). The dielectric analysis was carried out using a LCR meter (IM3536-Hioki). A 250 W high-pressure mercury lamp was used as a visible light source for the study of photocatalytic degradation of crystal violet (CV) dye. The prepared undoped BFO and Gd doped BFO (2 wt%, 5 wt% and 10 wt%) will be coded as Gd(0):BFO, Gd(2):BFO, Gd(5):BFO and Gd(10):BFO respectively.