Journal articles: 'BiFeO3'

1

William, R. V., A. Marikani, and K. Gangatharan. "Investigation of Multiferroic BiFeO3 Nanorods Using 2-MOE(C3H8O2)-Assisted Citrate Sol–Gel Method." International Journal of Nanoscience 18, no. 05 (July 24, 2019): 1850029. http://dx.doi.org/10.1142/s0219581x18500291.

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Bismuth ferrite (BiFeO[Formula: see text] nanorods have been prepared from 2-methoyethanol (2-MOE)-assisted sol–gel technique. Structure, dielectric, and magnetic properties of BiFeO3 nanorods are briefly discussed in this paper. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results suggest that the BiFeO3 peaks calcined at 500∘C exhibit a distorted rhombohedral perovskite structure with the absence of other secondary phases like Bi2Fe4O9. Meanwhile, the BiFeO3 showed excellent photoluminescence (PL) behavior due to the transmission of electrons from conduction band to the valence band. Ferroelectric hysteresis loop of BiFeO3 shows an increase of coercivity from 5.5–6[Formula: see text][Formula: see text]C/cm2 in a frequency range of 6–12[Formula: see text]kHz. The magnetization measurement resulted in a well-saturated ferromagnetic behavior, and in addition, the temperature-dependent magnetization was discussed for BiFeO3 nanorod using superconducting quantum interference device (SQUID) method. The zero-field-cooled (ZFC) and field-cooled (FC) curves reveal spin-glass effect owing to size effects, spin exchange, and anisotropy of material assembly.

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Salak, Andrei N., João Pedro V. Cardoso, Joaquim M. Vieira, Vladimir V. Shvartsman, Dmitry D. Khalyavin, Elena L. Fertman, Alexey V. Fedorchenko, et al. "Magnetic Behaviour of Perovskite Compositions Derived from BiFeO3." Magnetochemistry 7, no. 11 (November 16, 2021): 151. http://dx.doi.org/10.3390/magnetochemistry7110151.

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The phase content and sequence, the crystal structure, and the magnetic properties of perovskite solid solutions of the (1−y)BiFeO3–yBiZn0.5Ti0.5O3 series (0.05 ≤ y ≤ 0.90) synthesized under high pressure have been studied. Two perovskite phases, namely the rhombohedral R3c and the tetragonal P4mm, which correspond to the structural types of the end members, BiFeO3 and BiZn0.5Ti0.5O3, respectively, were revealed in the as-synthesized samples. The rhombohedral and the tetragonal phases were found to coexist in the compositional range of 0.30 ≤ y ≤ 0.90. Magnetic properties of the BiFe1−y[Zn0.5Ti0.5]yO3 ceramics with y < 0.30 were measured as a function of temperature. The obtained compositional variations of the normalized unit-cell volume and the Néel temperature of the BiFe1−y[Zn0.5Ti0.5]yO3 perovskites in the range of their rhombohedral phase were compared with the respective dependences for the BiFe1−yB3+yO3 perovskites (where B3+ = Ga, Co, Mn, Cr, and Sc). The role of the high-pressure synthesis in the formation of the antiferromagnetic states different from the modulated cycloidal one characteristic of the parent BiFeO3 is discussed.

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Dai, J. F., T. Xian, L. J. Di, and H. Yang. "Preparation ofBiFeO3-Graphene Nanocomposites and Their Enhanced Photocatalytic Activities." Journal of Nanomaterials 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/642897.

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BiFeO3nanoparticles were prepared via a polyacrylamide gel route. BiFeO3-graphene nanocomposites were fabricated by mixing BiFeO3nanoparticles and graphene into absolute ethanol solution followed by thermal drying. The TEM observation demonstrates that the BiFeO3nanoparticles are well anchored onto graphene sheets. The photocatalytic activities of the as-prepared samples were evaluated by the degradation of methyl orange (MO) under simulated sunlight irradiation. Compared to bare BiFeO3nanoparticles, BiFeO3-graphene nanocomposites exhibit enhanced photocatalytic activity. The outstanding photocatalytic performance is mainly ascribed to the efficient transfer of photogenerated electrons from BiFeO3to graphene, thus leading to an increased availability of h+for the photocatalytic reaction. In addition, hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and are found to be produced on the irradiated BiFeO3and BiFeO3-graphene nanocomposites; in particular, an enhanced yield is observed for the latter.

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Pema, Tenzin, Ankit Kumar, Babita Tripathi, Soumya Pandit, Sunil Chauhan, Satyendra Singh, Pritam Kumar Dikshit, et al. "Investigating the Performance of Lithium-Doped Bismuth Ferrite [BiFe1−xLixO3]-Graphene Nanocomposites as Cathode Catalyst for the Improved Power Output in Microbial Fuel Cells." Catalysts 13, no. 3 (March 20, 2023): 618. http://dx.doi.org/10.3390/catal13030618.

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In this study, multifunctional lithium-doped bismuth ferrite [BiFe1−xLixO3]-graphene nanocomposites (x = 0.00, 0.02, 0.04, 0.06) were synthesized by a sol-gel and ultrasonication assisted chemical reduction method. X-ray diffraction and FESEM electron microscopy techniques disclosed the nanocomposite phase and nanocrystalline nature of [BiFe1−xLixO3]-graphene nanocomposites. The FESEM images and the EDX elemental mapping revealed the characteristic integration of BiFe1−xLixO3 nanoparticles (with an average size of 95 nm) onto the 2D graphene layers. The Raman spectra of the [BiFe1−xLixO3]-graphene nanocomposites evidenced the BiFe1−xLixO3 and graphene nanostructures in the synthesized nanocomposites. The photocatalytic performances of the synthesized nanocomposites were assessed for ciprofloxacin (CIP) photooxidation under UV-visible light illumination. The photocatalytic efficiencies of [BiFe1−xLixO3]-graphene nanocomposites were measured to be 42%, 47%, 43%, and 10%, for x = 0.00, 0.02, 0.04, 0.06, respectively, within 120 min illumination, whereas the pure BiFeO3 nanoparticles were 21.0%. BiFe1−xLixO3 nanoparticles blended with graphene were explored as cathode material and tested in a microbial fuel cell (MFC). The linear sweep voltammetry (LSV) analysis showed that the high surface area of BiFeO3 was attributed to efficient oxygen reduction reaction (ORR) activity. The increasing loading rates of (0.5–2.5 mg/cm2) [BiFe1−xLixO3]-graphene composite on the cathode surface showed increasing power output, with 2.5 and 2 mg/cm2 achieving the maximum volumetric power density of 8.2 W/m3 and 8.1 W/m3, respectively. The electrochemical impedance spectroscopy (EIS) analysis showed that among the different loading rates used in this study, BiFeO3, with a loading rate of 2.5 mg/cm2, showed the lowest charge transfer resistance (Rct). The study results showed the potential of [BiFe1−xLixO3]-graphene composite as a cost-effective alternative for field-scale MFC applications.

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Wu, Mei Mei, Lin Feng He, Guo Hai Wei, and Yu Qing Li. "Crystal Structure and Multiferroic Behaviors of Solid Solution (1-y)BiFe_(1-x)Mn_xO₃-yBaTiO₃." Materials Science Forum 944 (January 2019): 526–30. http://dx.doi.org/10.4028/www.scientific.net/msf.944.526.

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It is expected that BiFeO3-based materials will have both ferroelectricity and ferromagnetism. (1-y)BiFe(1-x)MnxO3-yBaTiO3 system was prepared using solid state reaction method. The goal of this study is to uncover the impacts of Mn doping and BaTiO3 content on the crystal structure, magnetism and ferroelectric properties. By forming a solid solution with BaTiO3, stable perovskite BiFeO3 was achieved. The rhombohedrally distorted (1-y)BiFe(1-x)MnxO3-yBaTiO3 showed weak ferromagnetism due to the composition of BaTiO3 and the doping of Mn ion. 0.8BiFe0.9Mn0.1O3-0.2BaTiO3 and 0.7BiFe0.9Mn0.1O3-0.3BaTiO3 ceramics exhibited typical P-E hysteresis loops.

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Niu, Feng, Tong Gao, Laishun Qin, Zhi Chen, Qiaoli Huang, Ning Zhang, Sen Wang, Xingguo Sun, and Yuexiang Huang. "Polyvinyl Alcohol (PVA)-assisted Synthesis of BiFeO3 Nanoparticles for Photocatalytic Applications." Journal of New Materials for Electrochemical Systems 18, no. 2 (June 30, 2015): 069–73. http://dx.doi.org/10.14447/jnmes.v18i2.370.

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Bismuth ferrite (BiFeO3) is a promising material for visible light response photocatalytic applications. In the present work, BiFeO3 particles were synthesized by a polyvinyl alcohol (PVA)-assisted solid state reaction processing. The XRD pattern result indicated that the as-prepared particles are pure BiFeO3 crystalline phase. The microscopy observation demonstrated that the BiFeO3 particle size is from 100 to 200 nm, which is smaller than that of the BiFeO3 prepared without addition of PVA. The HRTEM showed that BiFeO3 particle is polycrystalline and contains many small crystal grains with different orientations. Furthermore, such nanosized and well-dispersed BiFeO3 particles exhibited a much higher photocatalytic activity than the prepared BiFeO3 without addition of PVA for the photodegradation of methyl orange contaminant under visible light irradiation.

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Di, Lijing, Hua Yang, Tao Xian, Xueqin Liu, and Xiujuan Chen. "Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation." Nanomaterials 9, no. 3 (March 9, 2019): 399. http://dx.doi.org/10.3390/nano9030399.

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Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.

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Sanga, Pascaline, Juanjuan Wang, Xin Li, Jia Chen, and Hongdeng Qiu. "Effective Removal of Sulfonamides Using Recyclable MXene-Decorated Bismuth Ferrite Nanocomposites Prepared via Hydrothermal Method." Molecules 28, no. 4 (February 5, 2023): 1541. http://dx.doi.org/10.3390/molecules28041541.

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Developing a simple and efficient method for removing organic micropollutants from aqueous systems is crucial. The present study describes the preparation and application, for the first time, of novel MXene-decorated bismuth ferrite nanocomposites (BiFeO3/MXene) for the removal of six sulfonamides including sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMZ), sulfamethazine (SMTZ), sulfamethoxazole (SMXZ) and sulfisoxazole (SXZ). The properties of BiFeO3/MXene are enhanced by the presence of BiFeO3 nanoparticles, which provide a large surface area to facilitate the removal of sulfonamides. More importantly, BiFeO3/MXene composites demonstrated remarkable sulfonamide adsorption capabilities compared to pristine MXene, which is due to the synergistic effect between BiFeO3 and MXene. The kinetics and isotherm models of sulfonamide adsorption on BiFeO3/MXene are consistent with a pseudo-second-order kinetics and Langmuir model. BiFeO3/MXene had appreciable reusability after five adsorption–desorption cycles. Furthermore, BiFeO3/MXene is stable and retains its original properties upon desorption. The present work provides an effective method for eliminating sulfonamides from water by exploiting the excellent texture properties of BiFeO3/MXene.

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9

Si, Yun-Hui, Yu Xia, Ya-Yun Li, Shao-Ke Shang, Xin-Bo Xiong, Xie-Rong Zeng, and Ji Zhou. "Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3." Modern Physics Letters B 32, no. 17 (June 18, 2018): 1850185. http://dx.doi.org/10.1142/s0217984918501853.

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A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

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10

Jiang, Yuanyuan, Rajesh Pathak, Tiansheng Zhang, Haibin Xu, Xiaoyi Li, Ronghua Jian, and Fan Wu. "Enhancement of Charge Transfer in TiO₂/BiOI Heterojunction Using BiFeO₃ as Interface Modifier for Photoelectrochemical Conversion." Journal of The Electrochemical Society 168, no. 11 (November 1, 2021): 116513. http://dx.doi.org/10.1149/1945-7111/ac393a.

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The solution-processed TiO2/BiFeO3/BiOI ternary heterojunction with cascade energy level alignments was developed for photoelectrochemical conversion, in which, BiOI was deposited on BiFeO3 sensitized TiO2 mesoporous film by spin-coating method. BiFeO3 as ferroelectric material was served here as a mediator for improvement of charge separation and transfer. The photocurrent generation in TiO2/BiFeO3/BiOI sample are very stable, even measured after 50 light on/off cycles with 2000 s. Moreover, compared with the TiO2/BiOI film, TiO2/BiFeO3/BiOI film showed about twice as high photocurrent density and photocatalytic activity. Kelvin probe force microscope showed that the surface potential of TiO2/BiFeO3/BiOI film was 0.456 V, which was obviously larger than 0.226 V in TiO2/BiOI sample. The increased surface potential should originate from the polarization electric-field E self by BiFeO3 interlayer, in which the direction of electric-field was directed toward the BiOI. The presence of E self consequently resulted in the better dissociation of photo-generated electrons and holes. Charge transport dynamics suggested that charge transfer rate increased from 6.813 s−1 of TiO2/BiOI heterojunction to 22.280 s−1 of TiO2/BiFeO3/BiOI heterojunction, and surface charge recombination rate reduced from 10.305 s−1 of the TiO2/BiOI to 7.707 s−1 of TiO2/BiFeO3/BiOI heterojunction, which results in the enhanced photoelectrochemical conversion in TiO2/BiFeO3/BiOI heterojunction.

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Bahboh, Abdalla, Abdul Halim Shaari, Hussein Baqiah, Soo Kien Chen, Mohd Mustafa Awang Kechik, Zainal Abdib Talib, and Mustafa Mousa Dihom. "Effect of Sol-Gel Synthesized BiFeO₃ Nanoparticle Addition in YBa₂Cu₃O_7–δ (Y123) Superconductor Synthesized by Standard Solid State Reaction Method." Solid State Phenomena 290 (April 2019): 245–51. http://dx.doi.org/10.4028/www.scientific.net/ssp.290.245.

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The effects of the multiforric BiFO3 nanoparticles addition on the structure and superconducting properties of YBa2Cu3O7–δ (Y123) with different concentrations were systematically investigated using X-ray diffraction (XRD), field emission scanning electron micrograph (FESEM), EDX and four point probe measurement. It was found that the added samples were predominant by Y-123 phase beside small amount of Y-211 and unreacted BiFeO3 secondary phases. Samples with less (wt.%) BFO added YBCO precursor powder preserved the orthorhombic structure similar to the pure YBCO, while samples with higher wt% addition show orthorhombic-to-tetragonal transition tendency. The samples became more porous and their grain size slightly decreased with addition of BiFeO3. The addition of nanoBiFeO3 disturbed the grain growth of Y123, thus resulting in the degradation of superconducting properties of the samples. The superconducting transition temperature (Tc onset) of samples decreased from 92 K for x=0.0 to 44 K for x=10.0 wt. %, which could be attributable to oxygen vacancy disorder.

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Pavlenko A. V., Stryukov D. V., Kudryavtsev Yu. A., Matyash Ya. Yu., and Malomyzheva N. V. "Preparation, structural features, elemental composition of and dielectric properties of a two-layer structure based on thin films of multiferroic BiFeO-=SUB=-3-=/SUB=- and ferroelectric (Sr, Ba)Nb-=SUB=-2-=/SUB=-O-=SUB=-6-=/SUB=-." Physics of the Solid State 64, no. 12 (2022): 1923. http://dx.doi.org/10.21883/pss.2022.12.54387.439.

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BiFeO heterostructures were manufactured using intermittent sputtering technology on the surface of a single crystal substrate MgO(001) BiFeO3/(Sr, Ba)Nb2O6. Studies of the structure, thickness profile of the composition, surface morphology and dielectric characteristics of materials have been carried out. It is established that despite the formation of two types of orientation domains (±18.4o) in the layer (Sr, Ba)Nb2O6, the upper layer of BiFeO3 is in the ratio of the total parallel orientation with the substrate MgO(001). It is shown that the composition of the films of bismuth ferrite and barium-strontium niobate does not change in film thickness, corresponds to the compositions of the sprayed ceramic targets, no signs of the presence of buffer layers were revealed. The results of the study of dielectric and ferroelectric characteristics of the heterostructure are presented. The reasons for the revealed patterns are discussed. Keywords: thin films, heterostructure, barium-strontium niobate, bismuth ferrite.

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Syed, Asad, Ashoka Siddaramanna, Abdallah M. Elgorban, D. A. Hakeem, and G. Nagaraju. "Hydrogen Peroxide-Assisted Hydrothermal Synthesis of BiFeO3 Microspheres and Their Dielectric Behavior." Magnetochemistry 6, no. 3 (September 9, 2020): 42. http://dx.doi.org/10.3390/magnetochemistry6030042.

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Despite considerable efforts undertaken in a rapidly developing area of multiferroic research, synthesis of phase pure BiFeO3 is still a matter of intensive research. In this work, we report the shape-controlled synthesis of pure BiFeO3 microspheres via a facile hydrothermal route. The prepared BiFeO3 powder has been characterized using powder X-ray Diffraction (XRD), Differential Thermal analysis (DTA), Scanning Electron microscopy (SEM), and impedance spectroscopy. Powder XRD analysis confirms the formation of pure rhombohedrally distorted perovskite with R3c space group. Scanning electron micrograph revealed that the prepared BiFeO3 microspheres are nearly spherical in shape with uniform size distribution. The BiFeO3 microspheres exhibit a dielectric constant value of ~110 at 1000 KHz, which is higher than the BiFeO3 prepared by conventional solid-state reaction and sol–gel method. Variation of dielectric constant with temperature at different frequencies shows that the BiFeO3 has a dielectric anomaly of ferroelectric to paraelectric type at 1093 K and this phenomenon is well supported by TGA results.

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Xu, Jia Huan, Hua Ke, De Chang Jia, Wen Wang, and Yu Zhou. "Preparation of BiFeO₃ Nanopowders Using Acetylacetone as Stabilizer." Key Engineering Materials 434-435 (March 2010): 314–17. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.314.

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The present investigation reports on the preparation of BiFeO3 nanopowders by a sol-gel method using acetylacetone as a stabilizer. Single-phase BiFeO3 nanopowders without any impurity or amorphous phases were obtained when the precursor was thermal treated at temperatures as low as 400 oC for 2 h. Acetylacetone (acac) plays an important role on lowering the formation temperature of pure phase BiFeO3 nanopowders. It is found that Bi/acac molar ratio of 1/30 was favorable for a stable sol and for the lowest crystallization temperature of pure BiFeO3 nanopowders. X-ray diffraction and Fourier transform infrared spectroscopy revealed that thermally induced crystallization process of BiFeO3 nanopowders from Bi-Fe polymeric precursor. When the thermal treated temperature was below 200 oC, only amorphous phase existed. With the temperature increasing up to 300 oC, crystallized phase, carbonate, were detected. After annealed at 400 oC, Bi-Fe precursor totally changed to rhombohedral BiFeO3 nanopowders. Scanning electron microscopy characterized morphologies of BiFeO3 nanopowders calcined at 400 oC and 500 oC. The ferroelectric transition of BiFeO3 nanopowders at 827 oC has been detected by differential thermal analysis.

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Hou, Jianfeng, and Haiwang Wang. "Synthesis and Characterization of Organic–Inorganic Complex." Journal of Nanoelectronics and Optoelectronics 16, no. 3 (March 1, 2021): 466–70. http://dx.doi.org/10.1166/jno.2021.2947.

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An new method is described for fabricating BiFeO3@PVDF composites using sultraviolet light to motivate the surface electronic of BFO conduct reduction system. The synthesis scheme consists of: (a) preparation of BiFeO3 nano particles using Hydrothermal synthesis method. (b) oxidation of the PVDF powders in the effect of the mixed gas (ozone and dioxygen) and sultraviolet light. (c) redox reaction of the oxidated PVDF and BiFeO3 nano particles in the effect of sultraviolet light. The synthesized BiFeO3@PVDF composites show that this method could increase the compatibility between PVDF and BiFeO3 nano particles. Moreover, a formation mechanism for the composite is proposed.

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Kang, Hyun Sik, Woo Seoung Kim, Yuwaraj K. Kshetri, Hak Soo Kim, and Hak Hee Kim. "Enhancement of Efficiency of a TiO2-BiFeO3 Dye-Synthesized Solar Cell through Magnetization." Materials 15, no. 18 (September 13, 2022): 6367. http://dx.doi.org/10.3390/ma15186367.

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Enhancement in the efficiency of a TiO2 dye-sensitized solar cell (DSSC) has been demonstrated by introducing ferromagnetic perovskite BiFeO3 and controlling the magnetic field, which induces two-dimensional material-like properties in the bulk of the TiO2-BiFeO3 DSSC (a 3-dimensional material). The effect of the concentration of BiFeO3 as well as the magnetization direction on the performance of the TiO2-BiFeO3 DSSC has been investigated. After magnetization, it was confirmed that the current density, efficiency, and open circuit voltage of the TiO2-BiFeO3 DSSC were increased. The observed phenomena have been explained in terms of the Hall effect which is responsible for the reduction of the degree of freedom of the electron movement resulting in the two-dimensional material-like properties in the bulk of the TiO2-BiFeO3 DSSC.

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Lu, Pengxian, Mankang Zhu, Dehe Xu, Wenjun Zou, Zhengxin Li, and Chunhua Wang. "Low-temperature sintering of PNW–PMN–PZT piezoelectric ceramics." Journal of Materials Research 22, no. 9 (September 2007): 2410–15. http://dx.doi.org/10.1557/jmr.2007.0322.

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For low-temperature firing of Pb0.94Sr0.06(Ni1/2W1/2)0.02(Mn1/3Nb2/3)0.07(Zr0.51Ti0.49)0.91O3 (PNW–PMN–PZT) system, BiFeO3 is selected as the sintering agent. In this study, the effects of BiFeO3 addition and sintering temperature on the microstructures and piezoelectric properties of the ceramics were investigated in detail. The ceramic with 10 mol% BiFeO3 sintered at 950 °C possesses optimal microstructure and piezoelectric properties. However, with the increase of sintering temperature the lower relative density, abnormal grain growth, and secondary phase accumulated at grain boundaries are observed, which deteriorates the piezoelectric properties. For the ceramics with different BiFeO3 addition sintered at 950 °C, the densification process and the grain growth are improved by suitable BiFeO3, while the morphotropic phase boundary (MPB) moving to the Ti-rich direction and the shrinkage of crystal cell occur. However, extra BiFeO3 inhabits the grain growth and introduces more cavities into the materials. Because of the microstructural changes that accompany the addition of BiFeO3 and the resulting decrease in sintering temperature, the maximum values of the piezoelectric properties are attained. By doping with 10 mol% BiFeO3, the sintering temperature of the PNW–PMN–PZT system can be lowered successfully from 1200 to 950 °C, while the excellent electric properties are kept.

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Li, Ya-Yun, Shao-Ke Shang, Yu Xia, Yun-Hui Si, Xin-Bo Xiong, Xie-Rong Zeng, and Ji Zhou. "Fabrication of dimension controlled BiFeO3 microcrystal." Modern Physics Letters B 33, no. 10 (April 10, 2019): 1950125. http://dx.doi.org/10.1142/s0217984919501252.

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In this research, the effect of different KOH concentrations on the bismuth ferrite (BiFeO3) phase formation and microcrystal size was discussed. Pure phase BiFeO3 microcrystals were successfully synthesized through controlling different KOH concentrations during the hydrothermal process. The diverse sizes of pristine BiFeO3 microcrystals were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Their photocatalytic activity was studied by photocatalytic degradation of methylene blue (MB) in aqueous solution under visible light irradiation. The results reveal that the composition and particle size of BiFeO3 microcrystals phase can be controlled with different mineralizer conditions. This work is able to provide a new perspective on the fabrication research of different dimension BiFeO3 microcrystals.

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Qi, Xi Wei, Xiao Yan Zhang, Xuan Wang, Hai Bin Sun, and Jian Quan Qi. "Preparation and Characterization of BiFeO₃Film via Sol-Gel Spin-Coating Process." Key Engineering Materials 492 (September 2011): 202–5. http://dx.doi.org/10.4028/www.scientific.net/kem.492.202.

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BiFeO3 thin films were spin-coated on conductive indium tin oxide (ITO)/glass substrates by a simple sol-gel possess annealed at 470-590°C. The crystal structure of as-prepared BiFeO3 thin films annealed at different temperature was determined to be rhombohedral of R3m space and free of secondary phases was also confirmed. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 thin film was about 320 nm. The double remanent polarization 2Pr of BiFeO3 thin film annealed at 500°C is 2.5 μC/cm2 without applied field at room temperature. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of BiFeO3 thin film was 6.13 nm.

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Mariam, Tamanna, and Shamima Choudhury. "Structural, Morphological and Magnetic Properties of Nd and Co co-doped BiFeO3 Ceramics at Room temperature." Journal of Bangladesh Academy of Sciences 41, no. 1 (August 23, 2017): 85–93. http://dx.doi.org/10.3329/jbas.v41i1.33506.

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Synthesis and characterization of BiFeO3 samples, co-doped with rare earth Nd and Co in place of Bi and Fe respectively were investigated at room temperature (RT). The formula of the four samples are Co-doped BiFe1xCoxO3 (x = 0.05-0.10) and Nd and Co co-substituted Bi0.95Nd0.05Fe0.95Co0.05O3 and Bi0.90Nd0.10Fe0.90Co0.10O3. These ceramic samples were synthesized by conventional solid state reaction method. The X-ray diffraction patterns clearly reveal that the secondary impurity phases were eliminated significantly due to the simultaneous substitution of Nd and Co in place of Bi and Fe respectively of BiFeO3 ceramics. The surface morphology of the synthesized samples was found to improve due to the simultaneous substitution of Nd and Co in place of Bi and Fe in BiFeO3. The average grain size of the first sample with 5% doping of Co in place of Fe was 1.5?m. In the second sample with 10% Co doping in place of Fe, the average grain size became 1.25 ?m. In presence of 5% Nd in place of Bi as well as with 5% doping of Co in place of Fe , grain size reduced to 0.75?m. The sample with 10% doping of Nd and Co in place of Bi and Fe respectively, average grain size decreased to 0.5?m. The EDX spectroscpoy ensured the presence of Bi, Nd, Fe, Co and O in these samples and their percentage of mass and atoms. Magnetic properties of the samples were also investigated at room temperature by measuring magnetization versus magnetic field (M-H) hysteresis loops. The wider loop clearly demonstrates the significant improvement of the magnetic behavior in 10% Nd and Co doped Bi0.90Nd0.10Fe0.90Co0.10O3 sample. The enhanced magnetic properties might be attributed to the substitution induced suppression of spiral spin structure of BiFeO3. The outcome of this investigation suggests the potentiality of the simultaneous doping of Nd and Co in BiFeO3 ceramics to improve their structural, morphological and magnetic characteristics.Journal of Bangladesh Academy of Sciences, Vol. 41, No. 1, 85-93, 2017

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Liao, Xiu Wei, Jun Zhu, Wen Bo Luo, and Lan Zhong Hao. "Structural and Electrical Properties of BiFeO₃ Fabricated on C-Sapphire Substrates Using a Double SrTiO₃/TiO₂ Buffer Layer." Materials Science Forum 687 (June 2011): 385–90. http://dx.doi.org/10.4028/www.scientific.net/msf.687.385.

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BiFeO3 (BFO) thin films were deposited by pulsed laser deposition (PLD) on c-plane sapphire substrates with a double SrTiO3/TiO2 oxide buffer layer grown by laser molecular beam epitaxy (laser-MBE). X-ray diffraction data showed the highly (111)-oriented perovskite phase in the BFO films with SrTiO3/TiO2 buffer layers, compared to the polycrystalline thin film grown directly on sapphire substrates. The epitaxial BiFeO3 thin films inherit its orientation from the underlying SrTiO3 buffer layer and have two in-plane orientations: (111)[1-10] BiFeO3 // (0001)[1-100] Al2O3 plus a twin variant related by a 180° in-plane rotation. The BiFeO3 thin films with the buffer layer show an out-of-plane remanent polarization of 81.5μC/cm2, which is comparable to the remanent polarization of BiFeO3 prepared on other single crystal substrates. Electrical measurements demonstrate that the BiFeO3 thin films with the buffer layer exhibit excellent fatigue endurance and a low leakage current density relative to the films without the buffer layer. These results indicate that the (111)-oriented BiFeO3 films with favorable electrical performance could be epitaxially grown on sapphire substrates using the double SrTiO3/TiO2 buffer layer.

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22

Matzen, S., S. Gable, N. Lequet, S. Yousfi, K. Rani, T. Maroutian, G. Agnus, H. Bouyanfif, and P. Lecoeur. "High piezoelectricity in epitaxial BiFeO₃ microcantilevers." Applied Physics Letters 121, no. 14 (October 3, 2022): 142901. http://dx.doi.org/10.1063/5.0105404.

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The large switchable ferroelectric polarization and lead-free composition of BiFeO3 make it a promising candidate as an active material in numerous applications, in particular, in micro-electro-mechanical systems (MEMS) when BiFeO3 is integrated in a thin film form on a silicon substrate. Here, 200-nm-thick Mn-doped BiFeO3 thin films have been epitaxially grown on a SrRuO3/SrTiO3/Si substrate and patterned into microcantilevers as prototype device structures for piezoelectric actuation. The devices demonstrate excellent ferroelectric response with a remanent polarization of 55 μC/cm2. The epitaxial BiFeO3 MEMS exhibit very high piezoelectric response with transverse piezoelectric coefficient d31 reaching 83 pm/V. The BiFeO3 cantilevers show larger electromechanical performance (the ratio of curvature/electric field) than that of state-of-art piezoelectric cantilevers, including well-known PZT (Pb(Zr,Ti)O3) and the hyper-active PMN–PT (Pb(Mg1/3Nb2/3)O3-PbTiO3). In addition, the piezoelectricity in BiFeO3 MEMS is found to depend on the ferroelectric polarization direction, which could originate from the flexoelectric effect and be exploited to further enhance the electromechanical performance of the devices. These results could potentially lead to a replacement of lead-based piezoelectrics by BiFeO3 in many microdevices.

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23

Xue, Xu, Guo Qiang Tan, Hui Jun Ren, and Meng Cheng. "Preparation of Nd and Co Co-Doped BiFeO₃ Thin Films Co-Doping Nd and Co by Sol-Gel Method." Key Engineering Materials 512-515 (June 2012): 1249–52. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.1249.

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BiFeO3 thin films co-doping Nd and Co were prepared on FTO/glass substrate by sol-gel method with Bi(NO3)3•5H2O, Fe•(NO3)3•9H2O, Nd(NO3)3•6H2O and Co(NO3)2•6H2O as raw materials, 2-methoxyethanol together with acetic anhydride as a solvent. XRD, FE-SEM, Agilent E4980A Precision LCR Meter and TF 2000 Ferroelectric Analyzer were used to characterize the structure, morphology, dielectric property and ferroelectric property of the BiFeO3 thin films. The results show that after Nd and Co co-doping, the BiFeO3 thin films still keep the perovskite structure. The crystal structure turns square or orthogonal from rhombus. The thickness of the BiFeO3 thin films is about 500nm and the grain size is 80nm to 30nm. BiFeO3 thin films co-doping Nd and Co have the larger dielectric constant and the lower dielectric loss compared with Nd doping. BiFeO3 thin films co-doping Nd10% and Co1% have the dielectric constant of over 170 and the dielectric loss of below 0.03. Both have the better frequency stability. Co-doping Nd and Co could decrease the coercive electric field of BiFeO3 thin films.

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24

Hohenberger, Stefan, Johanna K. Jochum, Margriet J. Van Bael, Kristiaan Temst, Christian Patzig, Thomas Höche, Marius Grundmann, and Michael Lorenz. "Enhanced Magnetoelectric Coupling in BaTiO3-BiFeO3 Multilayers—An Interface Effect." Materials 13, no. 1 (January 2, 2020): 197. http://dx.doi.org/10.3390/ma13010197.

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Combining various (multi-)ferroic materials into heterostructures is a promising route to enhance their inherent properties, such as the magnetoelectric coupling in BiFeO3 thin films. We have previously reported on the up-to-tenfold increase of the magnetoelectric voltage coefficient α ME in BaTiO3-BiFeO3 multilayers relative to BiFeO3 single layers. Unraveling the origin and mechanism of this enhanced effect is a prerequisite to designing new materials for the application of magnetoelectric devices. By careful variations in the multilayer design we now present an evaluation of the influences of the BaTiO3-BiFeO3 thickness ratio, oxygen pressure during deposition, and double layer thickness. Our findings suggest an interface driven effect at the core of the magnetoelectric coupling effect in our multilayers superimposed on the inherent magnetoelectric coupling of BiFeO3 thin films, which leads to a giant α ME coefficient of 480 Vc m − 1 Oe − 1 for a 16 × (BaTiO3-BiFeO3) superlattice with a 4.8 nm double layer periodicity.

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25

Yin, Shungao, Yanting Wu, Jiale Chen, Zhaoling Chen, Haoqing Hou, Qingyan Liu, Yuling Wang, and Wenbin Zhang. "Facile hydrothermal synthesis of BiFeO3 nanoplates for enhanced supercapacitor properties." Functional Materials Letters 11, no. 01 (February 2018): 1850013. http://dx.doi.org/10.1142/s1793604718500133.

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Perovskite BiFeO3 nanoplates were prepared via a facile hydrothermal method with NaOH as mineralizer. The obtained BiFeO3 nanoplates are about 30[Formula: see text]nm [Formula: see text] 90[Formula: see text]nm [Formula: see text]90[Formula: see text]nm in an average shape. This hydrothermal novel nanostructure with lots of defects largely enhances the specific capacitance compared with the electrochemically deposited BiFeO3 nanoparticles. The electrode of BiFeO3 nanoplates exhibits the highest specific capacitance of 254.6[Formula: see text]F g[Formula: see text] at a scan rate of 1[Formula: see text]mV s[Formula: see text] as well as good cyclic stability with 84% special capacitance retention after 1000 cycles. The prominent capacitive properties of hydrothermally obtained BiFeO3 suggest its promising application for supercapacitors.

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26

DING, HANG-CHEN, SI-QI SHI, WEI-HUA TANG, and CHUN-GANG DUAN. "FERROELECTRIC SWITCHING PATH IN MONODOMAIN RHOMBOHEDRAL BiFeO3 CRYSTAL: A FIRST-PRINCIPLES STUDY." Journal of Advanced Dielectrics 01, no. 02 (April 2011): 179–84. http://dx.doi.org/10.1142/s2010135x11000264.

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Based on density-functional calculations, we have studied possible ferroelectric switching path in monodomain single crystal of rhombohedral BiFeO3 , a prototypical multiferroic compound. By carefully studying the behaviors of FeO6 corner-sharing double-tetrahedrons, we find abrupt changes in total energy and oxygen atomic positions, and therefore polarizations, occur in the ferroelectric switching path of rhombohedral BiFeO3 . Detailed analyses suggest that such behavior might be caused by the frustrated magnetic ordering in the paraelectric phase of rhombohedral BiFeO3 , where three O atoms and the Bi atom are in the same plane perpendicular to the polarization direction. This is supported by the fact that the ferroelectric switching for paramagnetic BiFeO3 is smooth and has a much lower energy barrier than that of antiferromagnetic BiFeO3 .

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27

Jena, Soumyasree, Sanchari Bhattacharya, and Sanjoy Datta. "Evidence of half-metallic-2DHG at BiFeO₃ based heterointerfaces." Journal of Physics: Conference Series 2518, no. 1 (June 1, 2023): 012020. http://dx.doi.org/10.1088/1742-6596/2518/1/012020.

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Abstract The electronic properties of tetragonal BiFeO3 based hetero-structures, along with the tetragonal phase of SrTiO3 and PbTiO3 in (001) direction, is investigated with two types of interfaces. In the case of BiFeO3/SrTiO3(001) hetero-structure, the (FeO2)−/(SrO)0, and (BiO)+/(TiO2)0 interfaces are investigated respectively. For BiFeO3/PbTiO3(001) hetero-structure, the (FeO2)−/(PbO)0, and (BiO)+ / (TiO2)0 interfaces are studied. A tiny amount of half-metallicity has been found in the (FeO2)−/(SrO)0 interface while (BiO)+/(TiO2)0 interface behaves as metallic in the case of BiFeO3/SrTiO3(001) heterostructure. However, interestingly, (FeO2)−/(PbO)0 interface turns out to be a prominent half-metal with hole-type charge carriers, and (BiO)+/(TiO2)0 exhibits two-dimensional electron gas in the case of BiFeO3/PbTiO3(001).

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28

Wang, Zhen, Hai Yan Chen, Lin Qiang Gao, and Xin Zou. "Crystal Structure of BiFeO₃ Synthesized Using the Hydrothermal Processing." Key Engineering Materials 602-603 (March 2014): 947–50. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.947.

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BiFeO3 nanoparticles were successfully synthesized by a hydrothermal method by a mineralizer (KNO3). Structural characterization was performed by thermal analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (TEM).The results showed that the products were perovskite structure BiFeO3 powders. Optimal conditions for the synthesis of single-phase BiFeO3 ceramics were obtained.

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29

Ponraj, Caroline, D. Prabhakaran, G. Vinitha, and Joseph Daniel. "Photocatalytic Degradation of Direct Blue Dye by BiFeO₃ Nanoparticles under Visible Light Irradiation." Nano Hybrids and Composites 17 (August 2017): 194–201. http://dx.doi.org/10.4028/www.scientific.net/nhc.17.194.

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Citric acid assisted auto combustion method was used in the synthesis of BiFeO3 nanoparticles. The synthesized nanoparticles were characterised using X-ray powder diffraction, Scanning electron Microscope, BET surface area analysis, UV-Visible Diffuse Reflectance Spectrometer and Vibratory Sample Magnetometer. The photocatalytic behaviour of the BFO nanoparticles has been studied by the degradation of the direct blue dye. It is observed that BFO shows a good photocatalytic degradation of dye in the visible light irradiation. The effect of pH, catalyst quantity has been studied. The optimum condition is identified as pH 2 and 150mg of the photocatalyst in 10ppm of the dye solution. The magnetic property of BiFeO3at room temperature helps in the efficient removal of them from the treated dye solution. The ability of BiFeO3 nanoparticles to absorb the solar energy and using it for the treatment of water gives it an upper hand over other photo catalysts like Titanium Oxide (TiO2) and Zinc Oxide (ZnO).

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30

Xu, Fang Long, Peng Jun Zhao, Jia Qi Zhang, and Xin Qian Xiong. "Fluorine Doping Effects on the Electric Property of BiFeO₃ Thin Films." Applied Mechanics and Materials 624 (August 2014): 161–64. http://dx.doi.org/10.4028/www.scientific.net/amm.624.161.

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F doping BiFeO3-xFx (x=0, 0.02, 0.04, 0.06, 0.08) thin films were successfully fabricated on ITO/glass substrates by sol-gel method. X-ray diffraction analysis indicated that the un-doped BiFeO3 and F doping BiFeO3 thin films presented rhombohedral structure with the space group R3c. F-doping is found to significantly enhance the dielectric constant and decrease the leakage current density for x=0.08 compared with x=0. This study provides direct evidence that the multiferroic characteristics of BiFeO3 are sensitive to the anion doping, such as F, providing a convenient alternative to manipulate the electric polarization in multiferroic oxides.

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31

Zhu, Zhen Ye, Si Qi Wang, and Qian Wang. "Effects of Strain on Optical Properties of BiFeO₃: A First-Principles Study." Key Engineering Materials 703 (August 2016): 224–29. http://dx.doi.org/10.4028/www.scientific.net/kem.703.224.

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In order to investigate the effects of strain on optical properties of BiFeO3, electronic structure, dielectric properties and optical properties of BiFeO3 under different strain conditions were performed by first-principles calculations. Results show that the optical spectra of BiFeO3 is mainly determined by the contributions from transition from valence band O 2p to conduction band Fe 3d levels or even higher conduction band Bi 6s states in the low-energy region. Compared with equilibrium state, state density peaks shift to left side and state density peaks become broader and lower, and band gap becomes smaller under strain states. Furthermore, strain increases optical absorption coefficient peaks, energy loss coefficient peaks and reflectivity coefficient peaks, and extinction coefficient peaks, exhibiting that optical properites of BiFeO3 is improved under strain states. Our research provides theoretical guidance for future optical applications of BiFeO3, especially photovoltaic application.

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32

Reddy B, R., D. I. Halge, V. N. Narwade, J. W. Dadge, and K. A. Bogle. "Bipolar Resistive Switching Behaviour of Polycrystalline BiFeO₃ Thin Films Synthesized via Sol-gel Assisted Spin Coating Technique." Journal of Physics: Conference Series 2426, no. 1 (February 1, 2023): 012014. http://dx.doi.org/10.1088/1742-6596/2426/1/012014.

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Abstract Polycrystalline BiFeO3 thin films have been grown on glass substrates using a simple but efficient method commonly known as the spin coating technique. When used in a Cu / BiFeO3 / Cu configuration, the annealed BiFeO3 film (at 350 °C) exhibits bipolar resistive switching behaviour. The device shows stable resistive switching behaviour, where a stable hysteresis in the current–voltage curve was well developed by applying +/- 10 V at room temperature. The ratio of resistance in the high resistance state to the low resistance state of the device is ~ 104 with a good retention time of more than 106 min. The Poole–Frenkel emission at the Cu / BiFeO3 interface is proposed, and a redistribution of oxygen vacancies along the grain boundaries is found to play a key role in the resistance switching in the polycrystalline pure BiFeO3 films.

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33

Song, Wei, Yu-Zhang Fan, Yu Hua, and Wei-Feng Sun. "Magnetic and Dielectric Properties of Nano- and Micron-BiFeO3/LDPE Composites with Magnetization Treatments." Materials 13, no. 1 (December 26, 2019): 120. http://dx.doi.org/10.3390/ma13010120.

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By means of magnetization treatments at ambient temperature and elevated temperatures, the nano- and micron-bismuth ferrate/low density polyethylene (BiFeO3/LDPE) dielectric composites are developed to explore the material processing method to modify the crystalline morphology, magnetic and dielectric properties. The magnetic field treatment can induce the dipole in the LDPE macromolecular chain which leads to preferred orientation of polyethylene crystal grains to the direction of the magnetization field. The surface morphology of the materials measured by atomic force microscope (AFM) implies that the LDPE macromolecular chains in BiFeO3/LDPE composites have been orderly arranged and form thicker lamellae accumulated with a larger spacing after high temperature magnetization, resulting in the increased dimension and orientation of spherulites. The residual magnetization intensities of BiFeO3/LDPE composites have been significantly improved by magnetization treatments at ambient temperature. After this magnetization at ambient temperature, the MR of nano- and micron-BiFeO3/LDPE composites approach to 4.415 × 10−3 and 0.690 × 10−3 emu/g, respectively. The magnetic moments of BiFeO3 fillers are arranged parallel to the magnetic field direction, leading to appreciable enhancement of the magnetic interactions between BiFeO3 fillers, which will inhibit the polarization of the electric dipole moments at the interface between BiFeO3 fillers and the LDPE matrix. Therefore, magnetization treatment results in the lower dielectric constant and higher dielectric loss of BiFeO3/LDPE composites. It is proven that the magnetic and dielectric properties of polymer dielectric composites can be effectively modified by the magnetization treatment in the melt blending process of preparing composites, which is expected to provide a technical strategy for developing magnetic polymer dielectrics.

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34

Hang, Qi Ming, Xin Hua Zhu, Zhen Jie Tang, Ye Song, and Zhi Guo Liu. "Self-Assembled Perovskite Epitaxial Multiferroic BiFeO₃ Nanoislands." Advanced Materials Research 197-198 (February 2011): 1325–31. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.1325.

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Perovskite epitaxial multiferroic BiFeO3 nanoislands were grown on SrTiO3 (100) and Nb-doped SrTiO3 (100) single crystal substrates by chemical self-assembled method. Their phase structure and morphology were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy, respectively. The results showed that epitaxial multiferroic BiFeO3 nanoislands were obtained via post-annealing process in the temperature range of 650 - 800°C, and their lateral sizes were in the range of 50 - 160 nm and height of 6 -12 nm. With increasing the post-annealing temperature, the morphology of BiFeO3 nanoisland in the (100) growth plane evolved from tri-angled to squared, and then to plated shapes. By using piezo-force microscopy, ferroelectric characteristics of a single epitaxial BiFeO3 nanoisland (with lateral size of ~ 50 nm and height of 12 nm) grown on Nb-doped SrTiO3 (100) single crystal substrate, was characterized. The results demonstrated that fractal ferroelectric domains existed in the single BiFeO3 nanoisland, and self-biased polarization was also observed within this multiferroic nanoisland. This phenomenon can be ascribed to the interfacial stress caused by the lattice misfit between the BiFeO3 nanoisland and the SrTiO3 single crystal substrate.

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35

Priya, A. Sathiya, D. Geetha, J. M. Siqueiros, and Ștefan Ţălu. "Tunable Optical and Multiferroic Properties of Zirconium and Dysprosium Substituted Bismuth Ferrite Thin Films." Molecules 27, no. 21 (November 4, 2022): 7565. http://dx.doi.org/10.3390/molecules27217565.

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This work presents optical and multiferroic properties of bismuth ferrite thin films that are affected by zirconium and dysprosium substitution. Non-centrosymmetric BiFeO3,Bi0.95Zr0.05FeO3, and Bi0.95Dy0.05FeO3 thin films were coated on Pt/TiO2/SiO2/Si substrates using the spin coating method. The crystal structure, optical properties, microstructural, ferromagnetic, and ferroelectric properties of doped bismuth ferrite thin films were systematically investigated. From the XRD patterns, all the prepared thin films matched well with the rhombohedral structure with R3c space group with no observed impurity phases. The average crystallite size of the bismuth ferrite thin films were between 35 and 47 nm, and the size depended on the type of dopant. The determined energy band gap values of BiFeO3, Bi0.95Dy0.05FeO3, and Bi0.95Zr0.05FeO3 thin films were 2.32 eV, 2.3 eV, and 2 eV, respectively. Doping of Dy and Zr at the Bi site led to reduced surface roughness. The prepared thin films exhibited enhanced ferromagnetic and ferroelectric properties. The remnant magnetization of Zr-doped BiFeO3 was greater than that of the BiFeO3 and Dy-doped BiFeO3 thin films. From the obtained results, it was concluded that Zr-doped BiFeO3 thin films are suitable for solar cell fabrication.

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Xu, Hongxiang, Junhua Xu, Junlin Wei, and Yamei Zhang. "Fast Response Isopropanol Sensing Properties with Sintered BiFeO3 Nanocrystals." Materials 13, no. 17 (August 30, 2020): 3829. http://dx.doi.org/10.3390/ma13173829.

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BiFeO3 nanocrystals were applied as the sensing material to isopropanol. The isopropanol sensor based on BiFeO3 nanocrystals shows excellent gas-sensing properties at the optimum working temperature of 240 °C. The sensitivity of as-prepared sensor to 100 ppm isopropanol is 31 and its response and recovery time is as fast as 6 and 17 s. The logarithmic curves of the sensitivity and concentration of BiFeO3 sensors are a very good linear in the low detection range of 2–100 ppm. In addition, the gas sensing mechanism is also discussed. The results suggest that the BiFeO3 nanomaterial can be potentially applied in isopropanol gas detection.

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37

Yang, Lin Lin, Yong Gang Wang, Yu Jiang Wang, and Xiao Feng Wang. "Hydrothermal Synthesis and Characterization of BiFeO₃ Polyhedral Crystallites." Applied Mechanics and Materials 174-177 (May 2012): 508–11. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.508.

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BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.

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38

Liu, Xiaofen, Xiujuan Wang, Zirui Zhang, and Jin Cao. "Magnetic-Electric Behaviors and Physical Properties of The Thin Films on ITO-Glass Substrate." Journal of Physics: Conference Series 2083, no. 2 (November 1, 2021): 022070. http://dx.doi.org/10.1088/1742-6596/2083/2/022070.

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Abstract Polycrystalline BiFeO3 thin films on ITO glass substrates were prepared by radio frequency magnetron sputtering using a Bi1.1FeO3 target. The samples which were annealed with different annealing conditions are pure without impurities. We measured the magnetic properties and ferroelectricity of the BiFeO3 films. The measurement results show that the magnetic and electrical properties of the BiFeO3 films are significantly different under different annealing conditions.

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39

Yu, Xiao Hua, Hong Xing Gu, Bo Lin Wu, Jian Wang, Gang Qin Shao, Shi Xi Ouyang, and Xi Bao Li. "Preparation and Characteristics of BiFeO₃ Ceramics Doped by MnO₂ and Co₂O₃." Key Engineering Materials 434-435 (March 2010): 331–34. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.331.

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BiFeO3-based single-phase multiferroics have been widely studied in both ceramics and films. However, the macroscopic magnetic properties of BiFeO3 ceramics were now most very weak. In this work, MnO2 and Co2O3 were used as B-site substitutes in BiFeO3 ceramics in order to the enhancement of magnetic properties. The change of magnetization was analyzed based on the phase composition and the microstructure of ceramics.

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40

Zhao, Yajuan, Zhigang Yin, Xingxing Li, Maoyuan Zheng, Yong Cheng, Jinliang Wu, and Xingwang Zhang. "Domain matching epitaxy stabilized metastable, tetragonal BiFeO₃ on symmetry-mismatched c-plane ZnO." Japanese Journal of Applied Physics 61, no. 2 (January 20, 2022): 025501. http://dx.doi.org/10.35848/1347-4065/ac45a6.

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Abstract We report the stabilization of metastable tetragonal BiFeO3 epilayer on ZnO(0001) surface. X-ray reciprocal space map characterizations show that the BiFeO3 film is of true tetragonal symmetry, but not the commonly observed monoclinic structure. The critical thickness of the tetragonal BiFeO3 is higher than 140 nm, much larger than that reported previously. Despite the considerable lattice mismatch and symmetry mismatch, tetragonal BiFeO3 can be formed on ZnO(0001) though domain matching epitaxy which is featured by anisotropic growth. We show that by taking into account the elastic energy during the initial semi-coherent growth, the tetragonal phase is lower than the thermally stable rhombohedral phase in total energy by 70 meV per formula unit. Moreover, local piezoelectric characterizations reveal a coercive field of 360 kV cm−1 and a piezoelectric constant of 48 pm V−1. The integration of tetragonal BiFeO3 with robust ferroelectricity on the platform of ZnO has potentials for all-oxide electronics applications.

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Qi, Xi Wei, Xiao Yan Zhang, Xuan Wang, Hai Bin Sun, and Jian Quan Qi. "Preparation and Properties of Dy Doped La and Sc Solution of BiFeO₃ Film." Key Engineering Materials 537 (January 2013): 109–13. http://dx.doi.org/10.4028/www.scientific.net/kem.537.109.

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A series of Dy doped La and Sc solution of BiFeO3 thin films have been prepared by using spin-coating process on conductive indium tin oxide (ITO)/glass substrates, which a simple sol-gel possess is applied and annealed at 500°C. With the increase of content of Dy, the strongest peak (110) of La and Sc solution BiFeO3 film tends to further broaden. There is no second phase existence within the present Dy doping level. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 film was about 370 nm. For Dy doping level is 0.05, the maximum double remanent polarization 2Pr of as-prepared BiFeO3 thin film is15.44 μC/cm2. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of as-prepared BiFeO3 thin film is 2.11 nm. The dielectric constant of as-prepared films tends to firstly increase and then decrease with the increase of Dy content

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42

Yang, Xin, Gang Xu, Zhao Hui Ren, Gao Rong Han, and Ge Shen. "Effect of Poly Sodium-p-Styrenesulfonate on the Phase Formation and Morphology of the Hydrothermally Synthesized Bismuth Ferrite Powders." Materials Science Forum 745-746 (February 2013): 393–97. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.393.

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Rhombohedral bismuth ferrite (BiFeO3) powders were hydrothermally synthesized by using C6H8BiNO7 and Fe (NO3)·5H2O as precursors, KOH as a mineralizer and poly sodium-p-styrenesulfonate (PSS) as an additive. The phase formation and morphology of the as-prepared powders were characterized by X-ray diffraction,raman spectroscopy, and field-emission scanning electron microscopy. In order to investigate the effects of PSS, a series of experiments were performed by changing the introduced amount of PSS and the hydrothermal reaction time. The results showed that the introduction of the PSS leads to the synthesized bismuth ferrite changes from the mixture of Bi2Fe4O9 and BiFeO3 to pure rhombohedral BiFeO3. Corresponding to the phase composition evolution, the particle morphology alters from nanosheets to microparticles. The magnetic properties of single-crystalline BiFeO3 powders were also characterized. Based on the experimental results, the phase formation mechanism of the rhombohedral BiFeO3 hydrothermally synthesized assisted with PSS was discussed.

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43

Huang, Yao Ting, Xiu Li Fu, Xiao Hong Zhao, and Wei Hua Tang. "A Review of the Influential Factors on the Ferroelectric Domain Structure in BiFeO₃ Thin Films." Key Engineering Materials 544 (March 2013): 219–25. http://dx.doi.org/10.4028/www.scientific.net/kem.544.219.

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BiFeO3 is a very promising multiferroic materials, which can present ferroelectric and antiferromagnetic properties at room temperature (Tn=643 K, Tc= 1103 K). Ferroelectric domains in BiFeO3 thin films have attracted much attention due to their potential applications in memory devices. The aim of this paper is to review the main factors which can influence the ferroelectric domain structure in BiFeO3 thin films, including substrate, doping and film thickness.

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Silawongsawat, C., S. Chandarak, Thanapong Sareein, Athipong Ngamjarurojana, S. Maensiri, Pitak Laoratanakul, Supon Ananta, and Rattikorn Yimnirun. "Effect of Calcination Conditions on Phase Formation and Characterization of BiFeO₃Powders Synthesized by a Solid-State Reaction." Advanced Materials Research 55-57 (August 2008): 237–40. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.237.

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A perovskite-type phase of Bismuth Ferrite, BiFeO3, powder was synthesized by a solid-state reaction via a rapid vibro-milling technique. The effect of calcination condition on the phase formation, and characterization of BiFeO3 powder was investigated. The formation of the BiFeO3 phase investigated as a function of calcination conditions by TG–DTA and XRD. Morphology, particle size and chemical composition have been determined via a combination of SEM and EDX techniques and vibrating sample magnetometer (VSM) were used to characterize the structures and magnetic properties of prepared samples. The rapid vibro-milling is employed for the first time in this work as a significant time-saving method to obtain single-phase BiFeO3 powders.

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Tang, Pei Song, Hai Feng Chen, Feng Cao, Guo Xiang Pan, Min Hong Xu, Kun Yan Wang, and Yan Hua Tong. "Visible-Light Driven BiFeO3 Nanosized Photocatalysts Prepared by a Sol-Gel Process." Applied Mechanics and Materials 110-116 (October 2011): 1912–17. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1912.

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The single perovskite BiFeO3 nanoparticles were prepared by a sol-gel process. The BiFeO3 nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) method. It was found that the prepared BiFeO3 nanoparticles show the large specific surface area of 136 m2/g, and narrow band gap of 2.12 eV. Consequently, BiFeO3 nanoparticles show high visible-light photocatalytic activity for decomposition of methylene blue in comparison with the commercial Degussa P25. It is concluded that the large specific surface area and the narrow band gap contribute to the high visible-light photocatalytic activity through enhanced adsorption capability and visible-light absorption.

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46

Song, Ya Yu, Guo Qiang Tan, Hong Yan Miao, Ao Xia, Hai Yang Bo, and Yan Liu. "Synthesis and Characterization of BiFeO₃ on OH-Functionalized Organic SAMs by Metalorganic." Advanced Materials Research 105-106 (April 2010): 289–92. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.289.

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Polycrystalline BiFeO3 (BFO) thin films were grown via metal organic deposition method on OH-functionalized organic self-assembled monolayers (SAMs) on glass. The stable BiFeO3 precursor solutions were obtained by using iron nitrate and bismuth nitrate as raw materials, acetic acid and glycol as solvent and citric acid as chelating agent. Firstly, the preparation and functionalization of octadecyltrichlorosilane (OTS) self-assembled monolayers on the hydroxylated glass substrates was investigated. Water contact angle measurement and atomic force microscopy (AFM) confirmed the presence of a uniform, complete monolayer. After BiFeO3 was prepared on glass substrates, the film- forming and heat treatment processing of BiFeO3 films were studied. The BFO film was characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrograph (EDS). XRD pattern indicated that the grains of sample began to grow at 450 °C, and which was made up of BiFeO3 and some impure phase. With the increase of temperature, impure phase were disappeared and the intensity of diffraction peaks strengthened. Pure BiFeO3 phase were obtained at 500 °C ~ 600 °C. When the heat treatment temperature increased above 650 °C, the impure phase appeared. SEM showed that the BFO thin film possessed a dense microstructure on OH-functionalized SAMs.

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Li, Jin, Lei Wang, Liang Bian, Peng Jun Zhao, and Jin Bao Xu. "Structural Evolution and Electric Properties of Low Content Zr-Doped BiFeO₃ Thin Films." Advanced Materials Research 785-786 (September 2013): 817–20. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.817.

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The pure and Zr-doped BiFeO3 thin films were fabricated on Pt/TiO2/SiO2/Si substrates by sol-gel method. The microstructural characterization revealed a phase structural transition from rhombohedral structure to tetragonal structure in Zr-doped BiFeO3 thin films. Compared with pureBiFeO3 thin film, the Zr-doped BiFeO3 thin films showed better dielectric and leakage current characteristics. The mechanism associated with the enhancement of the electrical properties of the thin films is also discussed.

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48

Chandarak, S., Thanapong Sareein, Athipong Ngamjarurojana, S. Maensiri, Pitak Laoratanakul, Supon Ananta, and Rattikorn Yimnirun. "Effect of Calcination Conditions on Phase Formation and Characterization of BiFeO₃-BaTiO₃ Powders Synthesized by a Solid-State Reaction." Advanced Materials Research 55-57 (August 2008): 241–44. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.241.

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A perovskite-type phase of solid solution of BiFeO3-BaTiO3 powders were synthesized by a solid-state reaction via a rapid vibro-milling technique. The effect of calcination condition on the phase formation, and characterization of BiFeO3-BaTiO3 powders were investigated. The formation of the BiFeO3-BaTiO3 phase investigated as a function of calcination conditions by TG–DTA and XRD. Morphology, particle size and chemical composition have been determined via a combination of SEM and EDX techniques and vibrating sample magnetometer (VSM) was used to characterize the structures and magnetic properties of prepared samples. The rapid vibro-milling is employed for the first time in this work as a significant time-saving method to obtain single-phase BiFeO3-BaTiO3 powders.

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Wanchai, Katnanipa. "Photocatalytic Degradation of Phenol by Impure BiFeO₃ under Visible Light Irradiation." Key Engineering Materials 659 (August 2015): 274–78. http://dx.doi.org/10.4028/www.scientific.net/kem.659.274.

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Impure BiFeO3 as a visible light photocatalyst for phenol degradation was synthezied via solid state method. The calcined temperatures of catalysts were studied. The characteristics of the catalysts were determined by XRD, SEM/EDS and BET. The catalysts were mainly composed of rhombohedral distorted perovskite-type BiFeO3 phase with impurity phases (B2Fe4O9, Bi25FeO40 and Bi2O3). Photocatalytic activity of phenol (5 mg/l) was studied in the impure BiFeO3 illuminated with 200 w fluorescence lamps. The catalyst amount and initial pH value of phenol solution on the photocatalytic effiency have been also investigated. In the present experiments, the catalyst calcined at 800°C shows the highest activity. The optimum loading of impure BiFeO3 and pH value were obtained to be 0.5 g/l and 6, respectively.

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50

Zhang, Yaming, Bingbing Li, and Yanmin Jia. "High Humidity Response of Sol–Gel-Synthesized BiFeO3 Ferroelectric Film." Materials 15, no. 8 (April 17, 2022): 2932. http://dx.doi.org/10.3390/ma15082932.

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In this work, a BiFeO3 film is prepared via a facile sol–gel method, and the effects of the relative humidity (RH) on the BiFeO3 film in terms of capacitance, impedance and current–voltage (I–V) are explored. The capacitance of the BiFeO3 film increased from 25 to 1410 pF with the increase of RH from 30% to 90%. In particular, the impedance varied by more than two orders of magnitude as RH varied between 30% and 90% at 10 Hz, indicating a good hysteresis and response time. The mechanism underlying humidity sensitivity was analyzed by complex impedance spectroscopy. The adsorption of water molecules played key roles at low and high humidity, extending the potential application of ferroelectric BiFeO3 films in humidity-sensitive devices.

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Journal articles on the topic 'BiFeO3'

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