Papers by Keyword: Cobalt Ferrite

Abstract: Effect of the synthesis temperature on strontium-modified cobalt ferrite nanoparticles using co-precipitation method has been conducted. Molarity composition of strontium is 10%, chosen to substitute in the cobalt ferrite nanoparticles. Synthesis temperature treatment (75 °C, 85 °C, and 95 °C) is tuned the crystalline structures and magnetic properties of the cobalt ferrite nanoparticles. XRD result showed that the pattern of characteristics appropriates ICDD 22-1086, which describes that all peaks are pristine cobalt ferrite. Furthermore, crystallite size decreases with increasing synthesis temperature, i.e., 25.32 nm, 23.55 nm, and 22.65 nm at the temperatures of 75 °C, 85 °C, and 95 °C, respectively. FTIR obtained shows an absorption band at around 590 cm^-1 (tetrahedral site) and 387 cm^-1 (octahedral site), which is absorption from the original cobalt ferrite. VSM test also revealed changing magnetic properties with synthesis temperature treatment. In addition, squareness ratio showed that the magnitudes were greater than 0.5, which indicates single-domain magnetic. Hence, the adjustment of the synthesis temperature at 95 °C has the highest potential to advance applications such as photocatalytic and/or antibacterial due to its smallest crystallite size.

Abstract: Inherent magnetic features of engineered nanoparticles are quite important parameters for biomedical application. In this study, trying to process Bengawan Solo iron sand into a material that has potential for cobalt ferrite (CFO-NPs) and silver-cobalt ferrite (AgCFO-NPs) were synthesized by aqueous extract of tumeric. To modify the physical properties, annealing treatment was carried out at non-annealing temperatures and 500°C. The characterized by various instrument, and utilized for biomedical application with antibacterial activity. These are characterized XRD with showing results particle size was calculated by the Scherrer formula, which is around 19 nm to 25 nm. The results of FTIR peak adsorption at 400 and 600 cm^-1 it shows the characteristics of spinel ferrite and the presence of vibrations at tetrahedral and octahedral sites. The coerciveness field (Hc) while those subjected to annealing temperature treatment increased from 46 Oe to 136 Oe. Nanoparticles cobalt ferrite (CFO-NPs) and silver-cobalt ferrite (AgCFO-NPs) can be used as antibacterial application. The AgCFO-NPs material has an antibacterial function as seen in the antibacterial test. AgCFO-NPs showed a good response being able to inhibit the growth of Staphylococcus aureus and Eschericia coli bacteria. By the obtained result it can be claimed that material nanoparticles will be useful model for biomedical applications if they are explored at advance level.

Abstract: The current work concerns preparing cobalt manganese ferrite (Co_0.2Mn_0.8Fe₂O₄) and decorating it with polyaniline (PAni) for supercapacitor applications. The X-ray diffraction findings (XRD) manifested a broad peak of PAni and a cubic structure of cobalt manganese ferrite with crystal sizes between 21 nm. The pictures were taken with a field emission scanning electron microscope (FE-SEM), which evidenced that the PAni has nanofibers (NF_s) structures, grain size 33 – 55 nm, according to the method of preparation, where the hydrothermal method was used. The magnetic measurements (VSM) that were conducted at room temperature showed that the samples had definite magnetic properties. Additionally, it was noted that the saturation magnetization value of PAni/Co_0.2Mn_0.8Fe₂O₄ nanocomposite and Co_0.2Mn_0.8Fe₂O₄ nanoparticles are maximum saturation magnetization values of (4.7) and (9) emu g⁻¹ respectively. Studying properties of electrochemical which were tested in 1 M of H₂SO₄ by using the CV cyclic voltammetry analysis, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), found the highest capacitance is 596 F/g.

Abstract: The synthesis of zinc-substituted cobalt ferrite (Co_0.9Zn_0.1Fe₂O₄) using the sol gel method has been successfully carried out. The thermogravimetric analysis and differential thermal analyzer curve shows that at 400°C the Co_0.9Zn_0,1Fe₂O₄ sample has formed the final phase of nanoparticles. Therefore, the modification of physical properties was carried out by annealing treatment at temperature of 450°C, 550°C, 650°C, and 750°C. The X-rays diffraction show that all samples are in a single phase with a face center cubic space group Fd-3m structure according to the ICDD 221086. The crystal size increased with the annealing temperature 33.69 nm to 45.88 nm. The Co_0.9Zn_0.1Fe₂O₄ showed as excellent antibacterial properties on Staphylococcus aureus and Escherichia coli. The most superior antibacterial activity to Staphylococcus aureus was Co_0.9Zn_0,1Fe₂O₄ sample which was annealed at 650°C with a clear zone diameter of 39.81 mm. Meanwhile, the Escherichia coli bacteria which had the most superior antibacterial activity were Co_0.9Zn_0,1Fe₂O₄ samples which were annealed at 450°C with a clear zone measuring 21.04 mm.

Abstract: The effect of annealing temperature on the structural and magnetic properties of a rare earth (La³⁺) doped cobalt ferrite with fine sediment from the Bengawan Solo River as the source of Fe³⁺ has been studied. Co-presipitation method is use for preparation nanoparticles whole this experiment. In order to modified the physical properties, the annealing treatment of 2000C, 3000C, and 4000C are performed. The obtained nanoparticles are characterized their structural properties by using X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Then, magnetic properties evaluated by using Vibrating Sample Magnetometer (VSM). XRD results have shown that there is an increase in crystallite size with an increase in the given annealing temperature from 24.56 nm to 27.83 nm. The increase in crystallite size can be attributed to the increase in the internal energy of the crystal structure which promotes atomic diffusion. Meanwhile, there is a decrease in the value of the lattice parameter with an increase in the given annealing temperature. The decrease in lattice parameters with increasing crystallite size is generally due to the lattice parameters reaching a minimum energy with increasing crystallite size. The formation of La³⁺-O^2- for the incorporation of rare earth ions into the lattice requires high energy. The FTIR results show an absorption that appears at the peak around ~580 cm^-1. This indicates that the La³⁺ cation has successfully replaced the original structure of cobalt ferrite. The VSM results show that there is an increase in the value of Hc with an increase in the annealing temperature given from 100 Oe to 160 Oe. This is supported by the increase of anisotropy constant and increasing temperature annealing.

Abstract: In material science, doping method is employed to produce nanoferrites with desired characteristics. Recently, cobalt doped iron oxide nanomaterials have gained importance in industry for multiple electronic/electrical applications. Large number of methods have been adopted for the synthesis of nanoparticles (NPs), but high manufacturing cost, uniform sized, and anisotropic behaviors limit the commercial applications. In the presented work, cobalt doped (Co-Fe nanomaterials) are developed by a cost-effective sol-gel approach. The doped cobalt ferrites NPs (1%, 2%, and 3% doping of cobalt) were prepared and characterized by XRD, SEM & TEM, FTIR, and VSM techniques. XRD and microscopic (SEM & TEM) analysis revealed synthesis of hexagonal structured cobalt ferrite sized from ~16nm to ~8nm, with the increasing doping pattern of Cobalt from 1% to 3%. FTIR analysis showed the formation of well-structured oxides, which is in strong agreement with XRD and microscopy techniques. Moreover, VSM analysis revealed that cobalt ferrite nanoparticles possess ferromagnetic properties with Ms, Mr and Hc values of 0.038emu/g, 0.005emu/g and 405.19Oe respectively. In addition, squareness (Mr/Ms = 0.16) indicates the presence of single domain spherical particles.

Abstract: Thin film of cobalt ferrite has been deposited on glass substrate by a chemical spray pyrolysis technique using methanol solutions at 400^◦C substrate temperature. The uniformly deposited thin film were annealed at 500 ^◦C and studied their structural, infrared and optical properties using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectroscopy (UV-Vis), respectively. The X-ray diffraction patterns revealed single phase cubic spinel structure with space group Fd-3m. The fundamental absorption bands related to octahedral and tetrahedral sites were confirmed by Fourier-transform infrared spectroscopy (FTIR) spectrum.The formation of cubic spinel crystal structure of the CoFe₂O₄ thin filmwere confirmed from exhibited strong absorption peaks around 530.21 and 451.48 cm⁻¹ by FT-IR spectra.The optical properties of the deposited thin film were studied by an absorbance spectrum found at 315 nm. The value of energy bandgap (2.4 eV) wasinvestigated by Tauc plot.The obtained results indicate the fabricated thin film is promising material for various applications.

Abstract: Pyrolysis of buckwheat straw with or without catalysts was investigated using the TGA-FTIR method to determine the influence of nickel and cobalt ferrites on the distribution of pyrolysis products. According to the obtained results, the overall shape of the thermogravimetric and derivative thermogravimetric curves is unchanged in the presence of nickel and cobalt ferrites but different weight losses were observed. All catalysts contribute to the formation of solid residue from BWS pyrolysis. The presence of cobalt ferrites exhibited the highest bio-oil yields, whereas the highest non-condensable gas yield and the lowest bio-oil yield was obtained with the addition of NiFe₂O₄ (1) catalyst. According to the obtained results, the ability of nickel and cobalt ferrites to catalyze deoxygenation reactions depends on the crystallite size. The nickel or cobalt ferrites with smaller crystallite size (15-22 nm) show a higher ability to catalyzed dehydration reaction than catalysts with larger crystallite size (45-54 nm).

Abstract: This study aimed to show the enhanced effect of nanoparticles cobalt ferrite CoFe₂O₄ with chlorhexidine on Enterococcus faecium isolated from failure root canal treatment cases. Sol-gel technique was used to prepare the spinel cobalt ferrite CoFe₂O₄ at 200 °C then sintering at 400 °C & 600 °C, whereas the antimicrobial susceptibility test of nanoparticles was carried out according to the Kirby-Bauer technique compared with chlorhexidine. Fifteen isolates of Enterococcus faecium obtained by inserting sterile paper points in root canals, from patients who consulted the Teaching Hospital of Dentistry College at the University of Mosul, Iraq. For the first time, results showed that the nanoparticle cobalt ferrite CoFe₂O₄ at 400 °C and 600 °C, when mixed with chlorhexidine, give the mean inhibition zone 8.5334 mm and 8.0667mm respectively, while the pure chlorhexidine was providing a mean inhibition zone of 3.1667 mm, and also the nanoparticles cobalt ferrite in both cases of sintering without mixing, there was no antimicrobial effect. Statistical analysis using Duncan showed significant differences among groups (p < 0.05).

Abstract: Magnetic property studies and the crystallite structures evolution of spinel ferrite CoFe₂O₄ particles are reported in this paper. The ferrite was prepared through mechanical milling of all alloy precursors and sintered at various temperatures of 800, 900, 1000, and 1100 °C to promote the crystalline structure. X-ray diffraction (XRD) and Williamson-Hall plot were used to calculate the mean crystallite size and microstrain. Changes in the microstructure and crystallite sizes were occurring due to sintering treatments. It is found that the remanence (M_r) and saturation magnetization (M_s) increase with increasing sintering temperature, but a decrease occurred only at the temperature of 1100 °C. The optimum magnetic properties were obtained in a sample sintered at 1000 °C with a value of M_r = 36.00 emu/g and M_s = 74.05 emu/g.