Bismuth Phase Research Articles

Impact of Neodymium substitution on electrical properties in mixed phase of Bismuth containing pyrochlore (Bi2Sn2O7 and Bi2O3–SnO2)

Impact of Neodymium substitution on electrical properties in mixed phase of Bismuth containing pyrochlore (Bi2Sn2O7 and Bi2O3–SnO2)

Bismuth doping for enhanced physical and electrochemical properties of CuO–ZnO thin films for complete degradation of Rifampicin and other antibiotics alongside organic dyes

In the current Study, undoped and bismuth doped CuO + ZnO coupled oxide thin films were meticulously deposited on glass substrates utilizing the spray pyrolysis technique. The effect of bismuth doping level in the structural, morphological, optical, electrical and electrochemical properties of these thin films were systematically investigated. X-ray diffraction patterns unequivocally confirmed the polycrystalline nature of the films, showcasing a combination of monoclinic CuO and hexagonal wurtzite ZnO phases. Furthermore, at a doping level of 8 %, the presence of the bismuth phase was observed, indicating its incorporation into the CuO–ZnO matrix. As the bismuth doping level increased, we observed a noticeable improvement in crystallinity and grain size. The distinctive characteristics of the developed thin films underscored a discernible enhancement in physical and electrochemical properties with the increase of bismuth doping level. Subsequently, The 8 % bismuth-doped CuO–ZnO thin films exhibit remarkable efficiency in degrading pharmaceutical compounds. Specifically, within a mere 2-h timeframe, these films demonstrate an exceptional degradation efficiency of 99 % towards Rifampicin, a widely used antibiotic. Moreover, their efficacy extends to other pharmaceutical pollutants, showcasing a significant degradation of 77 % for Ampicillin, an antibiotic commonly used to treat bacterial infections, and an even more substantial degradation of 90 % for Rhodamine B, a prominent dye compound. This underscores the promising potential of 8 % bismuth-doped CuO–ZnO thin films in addressing environmental and health-related challenges associated with pharmaceutical contaminants.

Exploring the ambient metastability of yttrium substituted Bi2O3 electrolyte materials

The phase stability of (Bi1-xYx)2O3 (0.1 ≤ x ≤ 0.275) solid state electrolytes synthesized using the sol-gel method was investigated over prolonged periods under ambient conditions. The cubic polymorph was found to be metastable under ambient conditions, particularly for 0.1 ≤ x ≤ 0.15 where significant cubic-to-tetragonal transformation occurred. Spontaneous minor formation of both the rhombohedral polymorph and a bismuth subcarbonate phase was evident across the doping range but with varied reproducibility. Aging was significantly more prevalent for samples that had only been calcined (at 450 °C) as compared to those that were subsequently annealed (at 750 °C). The more highly substituted annealed materials (0.25 ≤ x ≤ 0.275) were initially phase pure cubic and far more stable, yet some rhombohedral and bismuth subcarbonate phase formation was also seen. Although the initial source of carbon which leads to the formation of the subcarbonate phase is not known at this stage, several suggestions are made. Pelletisation with additional sintering, as well as annealing powder samples under an inert atmosphere, was also shown to enhance the long-term phase stability characteristics of the cubic phase. This is the first longer term (over 2 years) ambient phase aging study of substituted bismuth oxides.

Visible light-induced photocatalytic degradation of methylene blue dye using pure phase bismuth ferrite nanoparticles

The degradation of organic dyes in wastewater has become a significant environmental issue, requiring the development of degradation technologies that are both effective and environmentally friendly. The present study employed the sol-gel approach to synthesize nanoparticles of phase pure bismuth ferrite (BiFeO3). The nanoparticles were assessed for their ability to efficiently degrade methylene blue (MB) dye, especially under visible light irradiation. The X-ray diffractogram (XRD) confirmed the formation of BiFeO3 nanoparticles, with an average crystallite size of 48 nm. The material's band gap, with a value of 1.84 eV, demonstrates its capacity to effectively absorb light, including wavelengths within the visible spectrum. Scanning electron microscopy (SEM) was used to identify porous aggregated particles. Both Raman and Fourier transform infrared spectroscopy (FTIR) confirm the successful synthesis of pure BiFeO3 in the desired phase. The BiFeO3 photocatalyst exhibited a significant surface area and isotherms of type IV, a characteristic typically observed in mesoporous materials, as determined by the Brunauer-Emmett-Teller (BET) analysis. The efficacy of BiFeO3 nanoparticles in facilitating the decomposition of MB in a water-based solution was evaluated by visible light photocatalysis. An efficiency degradation of 98.49 % was recorded for MB within 2 h.

Microstructural Characterization of Sn57Bi1Ag Solder Alloy Joints

Sn57Bi1Ag alloy system meets the basic solderability requirements while reliability of solder is less known. The presence of intermetallics that form at the solder-joint interface and in the bulk solder is the primary reason to cause joint failure on simple loading. Furthermore, dissolution of soldered surface (copper, gold, silver, nickel, etc.) into the solder during reflow alters the composition of the interface leading to the formation of intermetallic phases. The present paper addresses the characterization of low temperature Sn57Bi1Ag solder alloy, its joint interface metallurgy and integrity. Generally, formation of intermetallic phases (Cu3Sn, Cu6Sn5, Ag3Sn, AuSn2, Ni3Sn4, etc.) at the solder-pad interface is in the range of 0.3 to 1.0µm. On thermal ageing at 75°C (0.55Tm), the intermetallic phases grow further up to 2.3µm, particularly CuSn and AuSn phases. In addition, to distributed eutectic tin (Sn) and bismuth (Bi) phases, fine eutectic tin and bismuth phases and primary tin (β-Sn) are also observed. Coarsening of Bi and Sn phases is noticed on thermal ageing (75°C and 100°C). The rate of coarsening increases with the supply of thermal energy promoting Sn/Bi atomic diffusion and movement of eutectic boundaries (grain boundaries). However, the Sn-Bi interface is stable without any significant changes in eutectic structures and its morphologies. The mechanical drop test of the Sn57Bi1Ag solder joint passed 120 drops, characteristic life corresponds to the number of drops for a failure of 63.2%. Evaluated as per JESD22-B111 specification to a maximum peak acceleration of 1500G and half-sine shock pulse duration of 0.5 milliseconds, soldered the alloy to copper OSP surface. The solder joint also passed 1200cycles evaluated at -40 to +125°C. Electrical connectivity of the solder joints soldered to ENIG plated test boards is recorded continuously. Crystallographic orientation of Sn and Bi second phases is observed using electron back scattered diffraction (EBSD) of thermal aged solder joints and are also presented in this paper.

Diffusion behavior of bismuth in eco-friendly Bi–S based free cutting steel at high temperature

Deformation cracks during continuous casting and hot rolling are easy to occur in the Bi–S based free cutting steel, and the cracks are related to the diffusion of bismuth. The diffusion behavior of bismuth in the steel and the effect of the microstructure and alloying elements were studied by the diffusion annealing experiment combined with SEM, EDS and TEM analysis. The results show that the bismuth tends to diffuse along the grain boundaries (GBs) and the interfaces between the MnS phase and steel matrix, and then enrich to form the bismuth phases. The bismuth phases with lower melting point would be in liquid form at high temperature and resulted in the cracks along the GBs and interfaces. The bismuth diffusion is more likely to occur toward the parallel rolling direction than the vertical rolling direction in the steel because of the pearlite and MnS phases with the long strip shape and banded distribution. The addition of boron and titanium has the effect of inhibiting the diffusion of bismuth in the steel, which is mainly attributed to the faster diffusion rate of boron and the priority to occupy the defect sites of the GBs and the interfaces between the MnS phase and steel matrix.

Occurrence Behaviors of As/Sb/Bi in Copper Anode Slime and Their Separation by Compound Leaching Followed by Stepwise Precipitation.

Copper anode slime is the main raw material for the extraction of rare and precious metals. However, the recovery of rare and precious metals still faces great challenges due to the variety of impurities and the complex occurrence phase. In view of this, this research focuses on the occurrence mineral phases of arsenic, antimony, and bismuth in copper anode slime, and the process consisting of chloride leaching and selective precipitation of arsenic and bismuth is proposed. The results show that in copper anode slime, As mainly exists in the form of arsenate, while Sb and Bi exist in the form of oxides. The arsenate and oxides of Sb and Bi can be effectively leached by using the compound leaching process in the chloride system. The leaching efficiencies of As, Sb, Bi, and Cu can reach 92.72, 99.98, 89.13, and 90.31%, respectively, using a H2SO4 concentration of 4 mol/L and a NaCl concentration of 120 g/L with a liquid-solid ratio of 10:1 at 70 °C for 2 h. After compound leaching, more than 98% of Sb and Bi can be separated by stepwise selective precipitation in the form of Sb4O5Cl2 and BiOCl by controlling the H+ concentration at 0.8 g/L and 0.2 g/L, respectively. After separation of Sb and Bi, the As-containing solution can be further treated by mature arsenic solidification technology. The copper-containing solution for removing arsenic, antimony, and bismuth can be returned to the electrolysis process for copper recovery. The proposed process realizes the effectively and environmentally friendly separation of As, Sb, Bi, and Cu from copper anode slime.

Shubnikov-de Haas (SdH) Oscillation in Self-Flux Grown Rhombohedral Single-Crystalline Bismuth

The historic de Haas-van Alphen effect observed in the late 1950s in CSIR-NPL by J.S. Dhillon and D. Shoenberg in pure bismuth and zinc metal is revisited in this article through a single-crystalline phase of bismuth crystal, which is observed in terms of resistivity as predicted by Shubnikov-de Haas (SdH) oscillations. The single crystal of bismuth is grown through solid-state reaction under an optimized heat treatment whose purity and structural phase are confirmed through XRD, SEM, and EDAX. The transport properties of single crystal show the presence of SdH oscillations from a temperature range of 2 to 10 K. The occurrence of oscillations in the transverse magnetic field confirms the presence of the Fermi surface. Landau level (LL) fan diagram reveals the presence of topological surface states and the Berry’s phase confirmation from temperature-dependent SdH oscillations, concluding the presence of a noble topological phase of bismuth exhibiting SdH oscillations.

Boosted photocatalytic performance of OVs-rich BiVO4 hollow microsphere self-assembled with the assistance of SDBS

In this study, monoclinic phase bismuth vanadate (BiOV4) photocatalyst with unique hollow microsphere morphology was successfully prepared by a hydrothermal method in the existence of sodium dodecyl benzene sulfonate (SDBS). The prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron (SEM) and X-ray photoelectron spectrometer (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). Experimental results show that SDBS definitely changes the microstructure of BiVO4, which is allocated to the template role of SDBS in the preparation process. Moreover, the hydrothermal treatment time is also of crucial importance in affecting the structure and morphology of the photocatalysts, and the optimal hydrothermal treatment time for the formation of hollow microsphere is 24 h. Furthermore, the feasible growth mechanism for hollow microsphere was elaborated. Enriched oxygen vacancies (OVs) are introduced into BiOV4 prepared with SDBS, largely elevating the separation efficiency of photo-generated charges. Under visible light irradiation, the photocatalytic activities of BiOV4 for destruction of rhodamine (RhB) were evaluated. The photocatalytic degradation rate constant of RhB on the 3SBVO is 2.23 times of that on the blank BiOV4 as the mass ratio of SDBS/BiOV4 is 3 %. Photocatalytic degradation mechanism of BiVO4 toward detoxification of organic pollutants was presented.

Bi to β-Bi2O3 thin films transformation by thermal oxidation in air at low temperature

Bismuth oxidation by thermal treatment has been studied by several groups, however, low temperature (well below melting) oxidation is rarely reported in the literature. In this work, we focused on the straightforward phase transition from bismuth to the β-Bi2O3 phase, by gradually heating the bismuth film. This is proved that by carrying out the oxidation process at the low temperature 175 °C (as compared to the melting temperature 271 °C) it is possible to turn pristine bismuth into β-Bi2O3. In order to achieve this transformation, the thermal treatment was span for up to 10 h, finding that at 6 h the initially opaque bismuth film becomes optically translucid, meaning that the bismuth oxide beta phase is reaching downwards to the substrate. For 8 and 10 h of thermal treatment the bismuth film is clearly fully oxidized. The bismuth to β-Bi2O3 transformation was characterized by using Raman micro-spectroscopy, UV–Vis Spectroscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Our results demonstrated a feasible, simple and reliable method for the synthesis of β-Bi2O3, at well below melting temperature.

Effect of sintering temperature on the structural properties for CaBi4Ti4O15 compound

Polycrystalline CaBi4Ti4O15 (CBT) ceramics were successfully prepared by traditional ceramic technique. The X-ray diffraction spectrum of produced powder was studied at different temperatures (650 C, 850 C, and 1050C. The sintering temperature is very effective factor to obtained high crystallinity with very pure for CBT compound. The product structures analyzed using X-ray diffraction, it confirms, high purity polycrystalline phase formation revealed the existence of bismuth layered perovskite phase Aurivillius orthorhombic crystal structure at 1050ᶹ C. The produced samples' A field emission scanning electron microscope was used to analyze the morphologies (FESEM). It shows crystallites particles in the range about 149-349 nm for the product sintered at1050ᶹ C, it shows a dense microstructure with the presence of large orthorhombic distortion. The dielectric constant and dielectric loss were measured at room temperature as a function of frequency. The dielectric constant of CBT increases in sintering temperature. Moreover, the samples sintered at 1050 ᶹC exhibits good dielectric properties and lower value of tan .

The Crystalline Structure of Thin Bismuth Layers Grown on Silicon (111) Substrates.

Bismuth films with thicknesses between 6 and ∼30 nm were grown on Si (111) substrate by molecular beam epitaxy (MBE). Two main phases of bismuth — -Bi and -Bi — were identified from high-resolution X-ray diffraction (XRD) measurements. The crystal structure dependencies on the layer thicknesses of these films were analyzed. -Bi layers were epitaxial and homogenous in lateral regions that are greater than 200 nm despite the layer thickness. Further, an increase in in-plane 2 values showed the biaxial compressive strain. For comparison, -Bi layers are misoriented in six in-plane directions and have -Bi inserts in thicker layers. That leads to smaller (about 60 nm) lateral crystallites which are compressively strained in all three directions. Raman measurement confirmed the XRD results. The blue-sift of Raman signals compared with bulk Bi crystals occurs due to the phonon confinement effect, which is larger in the thinnest -Bi layers due to higher compression.

Effects of Fluorination and Molybdenum Codoping on Monoclinic BiVO4 Photocatalyst by HSE Calculations.

Monoclinic phase bismuth vanadate (BiVO4) is one of the most promising photoelectrochemical materials used in water-splitting photoelectrochemical cells. It could be even better if its band gap and charge transport characteristics were optimized. Although codoping of BiVO4 has proven to be an effective strategy, its effects are remarkably poorly understood. Using the Heyd–Scuseria–Ernzerhof (HSE) hybrid functional, we estimate the formation energy, electronic properties, and photocatalytic activities of F and Mo codoped BiVO4. We find that Mo atoms prefer to replace V atoms, whereas F atoms prefer to replace O atoms (FOMoV-doped BiVO4) under oxygen-poor conditions according to calculated formation energies. BiVO4 doped with FOMoV is found to be shallow-level doped, occurring with some continuum states above the conduction band edge, which is advantageous for photochemical catalysis. Moreover, FOMoV-doped BiVO4 shows absorption stronger than that of pure BiVO4 in the visible spectrum. Based on the band-edge calculation, BiVO4 doped with FOMoV still retains a high oxidizing capacity. It has been shown that FOMoV-doped BiVO4 exhibits a very high photocatalytic activity under visible light.

Microwave-Assisted Solvothermal Route for One-Step Synthesis of Pure Phase Bismuth Ferrite Microflowers with Improved Magnetic and Dielectric Properties.

The prototypical plum-free, one-phase multiferric ferrite BiFeO3 (BFO) is solid, parallel, with a high ferroelectric Curie temperature and Neel temperature and antiferromagnetic and ferroelectric propagation. This work aims to synthesize pure-phase BFO in the quickest possible way. We followed the microwave-assisted solvothermal (MWAST) method to achieve pure-phase BFO in the shortest duration of 3 min. The experiment involves simple optimizations with KOH concentration and microwave power levels. The surface morphology along with magnetic properties of BFO synthesized via the MWAST method are altered with varying KOH concentrations and microwave (MW) power levels. Our X-ray diffraction findings reveal that the pure-phase BFO is formed at 800 W MW power, and the structural characterizations like transmission electron microscopy, field emission scanning electron microscopy with energy-dispersive X-ray analysis have displayed the formation of uniformly distributed spherical microflowers of pure-phase BFO exhibiting a single-crystalline nature. Besides, the magnetic measurements affirmed a reliable weak ferromagnetic behavior (magnetization ∼1.25 emu/g) in BFO synthesized at 800 W MW power. In addition, good dielectric behavior with low dielectric loss was accompanied by frequency-dependent dielectric studies indicating an excellent frequency response of the material, and also the room-temperature ferroelectric properties were studied using a ferroelectric analyzer. The polarization of pure-phase BFO increases with the applied electric field and exhibits unsaturated polarization–electric field loops due to leakage current. Moreover, the Fourier transform infrared spectrum of the synthesized material has indicated the pure-phase BFO, and the Raman data have elucidated the vibrational modes of BFO. Further, the analysis of X-ray photoelectron spectroscopy data has confirmed the presence of fewer Fe2+ ions and oxygen vacancies in the pure-phase BFO. Therefore, the collective characterizations and detailed analysis of BFO material have revealed the uniqueness of the MWAST method in producing the pure-phase BFO in 3 min with improved magnetic and dielectric properties, and hence the BFO synthesized via the MWAST method can be a potential candidate for multiferroic applications.

Numão gold deposit in the Iberian Variscan belt, Northern Portugal: Ore features and mineralization controls. A gold deposit in a W-Sn metallogenic province

The Numão gold deposit in the northern part of the Iberian Variscan belt is close to the regional first-order Vilariça-Manteigas fault system. The second and third-order structures controlled the gold mineralized bodies. These bodies consist of disseminated sulfides, arsenopyrite-quartz veins, and sulfides-scheelite-quartz veins. The scheelite occurrence predates the gold mineral assemblage and is lithologically controlled by host rocks with calc-silicate minerals. The ore mineral assemblage comprises scheelite, arsenopyrite, chalcopyrite, bismuth, and Au-Ag mineral phases, with minor pyrite, pyrrhotite, sphalerite, and galena. The hypogene gold minerals at Numão deposit are hosted by arsenopyrite, chalcopyrite, and silicate matrix in minor amounts. Chemically, gold fineness ranges from 663 to 841. The thermal evolution of the mineralization was estimated based on arsenopyrite (381° to 502 °C) and chlorite geothermometers (264° to 341 °C). The multi-element and principal component analysis information was used to better identify geochemical patterns and trends in hydrothermal alteration. The gold-metal association (Au-As-W-Bi) was found to be similar to other gold deposits in the European Variscan belt.

Structural and superconducting properties of low-temperature ultrathin PbBi<sub>3</sub> films

Bismuth (Bi), as a stable heaviest element in the periodic table of elements, has strong spin-orbit coupling, which has attracted a lot of attention as the parent material of various known topological insulators. Previous calculations predicted that Bi(111) with a thickness less than eight bilayers and the ultrathin black-phosphorus-like Bi(110) films are single-element two-dimensional (2D) topological insulators. However, it is generally believed that these crystalline bismuth phases are not superconducting or their transition temperature should be lower than 0.5 mK. Lead (Pb) is a good superconducting elementary material, and there is a relatively small difference in radius between the Bi atom and Pb atom. According to the Hume-Rothery rule, it is expected that Pb/Bi alloys in an arbitrary ratio should be superconducting. One may thus expect to form crystalline Bi based superconductors by Pb substitution, which might host intriguing topological superconductivity. While our previous work has demonstrated a low-temperature stable Pb<sub>1–<i>x</i></sub>Bi<sub><i>x</i></sub> (<i>x</i>~0.1) alloy phase in which Pb in the Pb(111) structure is partially replaced by Bi, the Bi crystalline structure-based phases of the superconducting alloys still lack in-depth research. Here, we report a new low-temperature phase of Pb-Bi alloy thin film, namely PbBi<sub>3</sub>, on the Si(111)-(7 × 7) substrate, by co-depositing Pb and Bi at a low temperature of about 100 K followed by an annealing treatment of 200 K for 2 h. Using low-temperature scanning tunneling microscopy and spectroscopy (STM/STS), we characterize <i>in situ</i> the surface structure and superconducting properties of the Pb-Bi alloy film with a nominal thickness of about 4.8 nm. Two spatially separated phases with quasi-tetragonal structure are observed in the surface of the Pb-Bi alloy film, which can be identified as the pure Bi(110) phase and the PbBi<sub>3</sub> phase, respectively, based on their distinct atomic structures, step heights and STS spectra. The PbBi<sub>3</sub> film has a base structure similar to Bi(110), where about 25% of the Bi atoms are replaced by Pb, and the surface shows a <inline-formula><tex-math id="M2">\begin{document}$\sqrt 2 \times \sqrt 2 R{45^ \circ }$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M2.png"/></alternatives></inline-formula> reconstructed structure. The superconducting behavior of the PbBi<sub>3</sub> phase is characterized using variable-temperature STS spectra. We obtain that the superconducting transition temperature of PbBi<sub>3</sub> is about 6.13 K, and the <inline-formula><tex-math id="M3">\begin{document}$2\varDelta (0)/{k_{\text{B}}}{T_{\text{c}}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M3.png"/></alternatives></inline-formula> ratio is about 4.62 using the fitting parameter of <inline-formula><tex-math id="M4">\begin{document}$\varDelta (0) = 1.22{\text{ meV}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220050_M4.png"/></alternatives></inline-formula> at 0 K. By measuring the magnetic field dependent superconducting coherence length, the critical field is estimated at larger than 0.92 T. We further investigate the superconducting proximity effect in the normal metal-superconductor (N-S) heterojunction consisting of the non-superconducting Bi(110) domain and the superconducting PbBi<sub>3</sub> domain. The N-S heterojunctions with both in-plane configuration and step-like configuration are measured, which suggest that the atomic connection and the area of the quasi-2D Josephson junctions and the external magnetic field can affect the lateral superconducting penetration length. We also observe the zero-bias conductance peaks (ZBCPs) in the superconducting gap of the PbBi<sub>3</sub> surface in some cases at zero magnetic field. By measuring d<i>I</i>/d<i>V</i> spectra at various temperatures and by adopting a superconducting Nb tip, we identify that the ZBCP originates from the superconductor-insulator-superconductor (S-I-S) junction formed between a superconducting tip and the sample. Nevertheless, the Bi(110)-based PbBi<sub>3</sub> phase may provide a possible platform to explore the intriguing topological superconducting behaviors at the vortexes under magnetic fields, or in the vicinity of the potentially topological superconducting Bi(110) islands by considering the proximity effect.

Multiferroic based microwave devices

Recently, there has been significant interest on the fundamental science and technological applications of complex oxides and multiferroics. Low-power multiferroic have potential to fabricate and characterize frequency tunable, compatible with MMIC Technology, small light-weight for hand-held operation, cost-effective, high-frequency (>10GHz), devices for next generation communication devices and military applications. Multiferroic materials consists of both magnetic and ferroelectric phase and they offer the possibility of magneto-electric (ME) coupling. The purpose of this research is to show strong magnetic field dependent frequency tuning of multiferroics (Nickel doped BFO – BiFe1-xNixO3) based devices over a broad frequency band. We have shown here the magnetic field control of ferromagnetic resonance (FMR) field/frequency from C to Ku band frequencies. Nanoparticles of BiFe1-xNixO3 (x=0.025 & 0.05) were prepared by auto combustion method. The XRD study confirms the formation of pure phase Bismuth Ferrite Nanoparticles. Ferromagnetism of un-doped BFO was enhanced by Ni substitution. Microwave characterization was done in co-planar waveguide (CPW) geometry both in field sweep and frequency sweep mode. BiFe1-xNixO3 nanoparticles were deposited using electrophoretic deposition method (EPD) on top of CPW to do the FMR experiments. The operating frequency of the device was tuned by application of magnetic field (H) over a wide range (5 to 20 GHz) with a field up to 8 kOe.

Creation and research of new bioindifferent photocatalysts that use the energy of solar radiation to purify wastewater from pollutants

This work is devoted to the study of new bioindifferent photocatalysts that use the energy of solar radiation to purify water from organic pollutants. Photocatalytic materials were obtained by a previously developed low-temperature pyrolytic synthesis. Varying the bismuth content in the percursor mixture within 15-30 %, allows controlling the phase formation of the bismuth and strontium silicate phases. The samples obtained at 25 % bismuth in the precursor mixture (in terms of Bi2O3 %, wt.) show the highest photocatalytic activity with Bi12SiO2, Bi4Si3O12 formed in the catalyst composition. Photocatalytic activity of coatings with the predominance of bismuth silicates is inferior to coatings with the predominance of strontium bismuthates, but their greater hydrolytic stability is observed.

A facile strategy for the preparation of bismuth ferrite nanoparticles: Influence of calcination temperature on structural, dielectric, and morphological characteristics

Herein, Sol-Gel method was employed to synthesize single phase Bismuth Iron Oxide (BFO) nanoparticles. The effect of calcinating temperature (400–700 °C) on crystallinity of nano-samples has been studied. The improvement in crystallinity is evident from growth of crystallites with an average size between 12 and 15 nm. Further, the microstructural analysis performed with Scanning Electron Microscopy (SEM) which reveals an average size of grains i.e. (17–32 nm), consistent to XRD data. In addition, the dielectric constant of prepared nanoparticles was determined which demonstrate a substantial effect of annealing temperature. The minimum value of dielectric constant was achieved at higher frequency. Moreover, the temperature and frequency dependent tangent loss, dielectric constant and bulk modulus have been studied. Based on these excellent results, we suggest that our prepared BFO nanoparticles possess potential applications in advanced magneto and ferroelectric devices.

Structural and Optical Properties of BiFeO<sub>3</sub> via Polymer-Assisted Hydrothermal Synthesis under Different Weight of Chitosan

In this work, single phase Bismuth Ferrite, BiFeO3 was successfully synthesized by using hydrothermal method assisted with different weight (0.24 g, 0.36 g and 0.48 g) of Chitosan. Potassium hydroxide (KOH) were used as a mineralizer during the synthesis process for the precipitation. The samples were characterized for different properties such as structural and optical properties, and were then compared with previous works. The X-ray diffraction data for all the samples showed that the samples had a single phase belonging to R3c space group with perovskite rhombohedral structure at diffraction angle 32.0° to 32.5° even though the slight presence of secondary phase at diffraction angle 28° was detected. Scanning electron microscope revealed a decrement in particle size as the weight of Chitosan increased indicating effective used of Chitosan in controlling the agglomeration of the particles. All samples BiFeO3 assisted with and without Chitosan showed significant enhancement in energy gap where the obtained results showed a small energy gap values ranging from ~1.22 eV to ~1.88 eV determined from UV-vis absorbance characterization. Therefore, by the addition of Chitosan, the properties of BiFeO3 such as structural and optical have changed as well as preventing from the particle to agglomerate.