Papers by Keyword: Fe₃O₄

Abstract: We report double scaling electrical transport in (Fe₃O₄)_1-x/(BaTiO₃)ₓ nanoparticle-composite sinters (NPCSs), where charge conduction arises from the coexistence of variable range hopping and percolation. Understanding the interplay between these mechanisms is essential for designing composite materials in which microstructural connectivity and carrier localization can be tuned for targeted electronic properties. The NPCSs were synthesized via low-temperature hydrogen reduction and sintering of α-Fe₂O₃ and BaTiO₃ nanoparticles (average diameter ~100 nm) at 500 °C for 3 h in an Ar (90%)/H₂(10%) atmosphere, yielding x values from 0.0 to 0.7. X-ray diffraction and scanning electron microscopy confirmed phase purity, the coexistence of Fe₃O₄ and BaTiO₃, and systematic grain-size evolution with BaTiO₃ content. Electrical resistivity increased with x and followed 3D Mott’s variable range hopping behavior, with ln ρ vs. T ⁻¹ᐟ⁴ (ρ: electrical resistivity; T: temperature) remaining linear and slopes increasing with x, consistent with shorter hopping lengths and enhanced carrier localization. Percolation analysis in the 150–300 K range yielded a conductivity critical exponent of ~3, significantly higher than the ~2 predicted for simple 3D percolation, indicating that geometric connectivity alone cannot explain the transport. These results provide compelling evidence that charge conduction in these composites is governed by a double scaling mechanism, in which variable range hopping and percolation coexist and jointly control electronic transport through the combined influence of microstructure and composition.

Abstract: Water pollution due to inadequate waste treatment causes damage to the ecosystem to various diseases in humans such as itching, and other skin diseases. One of the efforts to treat wastewater is photocatalyst. TiO₂ is one of the materials that can be used as wastewater treatment because it has good photocatalyst properties. However, TiO₂ has a wide band gap so that this material is only optimal at UV wavelengths. This can be overcome by adding Fe₃O₄ to TiO₂ which can help narrow the band gap and good magnetic properties so as to increase its photocatalyst activity. AC has advantages such as having a large cross-sectional area and being able to absorb waste well. AC/TiO₂/Fe₃O₄ nanocomposite was synthesized by hydrothermal method, then deposited on cork ball by spray coating and heating technique. SEM analysis showed that AC/TiO₂/Fe₃O₄ nanocomposites had an average size ranging from 124-225 nm and were successfully deposited on the surface of cork balls. In addition, the increase in porosity is related to the smaller diameter size with a large surface area. AC/TiO₂/Fe₃O₄ nanocomposites are dominated by the elements C, O, Ti, and Fe confirmed from EDX analysis. The smallest area is in sample 3 worth 1.39 m² /g and adsorbs the highest worth 116.33 nm so as to increase the effectiveness of the photocatalyst. Based on UV-Vis results, the absorption area of TiO₂ and Fe₃O₄ at a wavelength of 325 nm and in the AC/TiO₂/Fe3O₄ nanocomposite shows absorption between 295-330 nm. Fe₃O₄ has a relatively small band gap increase. The band gap energy of nanocomposite samples 1-5 decreased from 3.5 eV to 3.0 eV. O-H stretching vibrations in hydroxyl and carboxyl functional groups were confirmed with the addition of Fe₃O₄ mass. The most optimal river water photodegradation test results were shown in sample 3 with DO levels increased by 98.38%, phosphate levels decreased by 97.9% and water color decreased by 100%. After photodegradation for 150 minutes, the pH test results are still in accordance with the river discharge water quality standards. Overall, this material is very useful for the treatment of organic pollutants and wastewater.

Abstract: Nanocomposites, comprising reduced graphene oxide (rGO) and iron oxide nanoparticles (Fe₃O₄) have emerged as promising materials for various applications due to their exceptional properties. However, a critical research gap exists in understanding the electrostatic potential distribution within these complex molecular structures. This study aims to address this gap by employing advanced computational techniques to visualize the electrostatic potential within rGO/ Fe₃O₄ nanocomposites at the molecular level. The primary objective of this study is to map the spatial distribution of the electrostatic potential within rGO/Fe₃O₄ nanocomposites. This will provide molecular-level insights into the electrostatic environment and its influence on electronic structure, reactivity, and intermolecular interactions. By correlating the electrostatic potential with material properties, such as reactivity and stability, we aim to enable the rational design of improved nanocomposites. The novelty of this research lies in its interdisciplinary approach, bridging materials science, chemistry, and physics. The outcomes are expected to have significant implications for optimizing the performance of rGO/Fe₃O₄ nanocomposites in applications ranging from energy storage to catalysis and beyond. This study contributes to our fundamental understanding of nanocomposite behavior and paves the way for enhanced materials design.

Abstract: The potential application for magnetic hyperthermia of green synthesized Fe₃O₄ nanoparticles using Moringa Oleifera (MO) extract was investigated. We modified the amount of MO extract solution by 10 and 20 mL to determine its effect on microstructure, magnetic properties, and heating efficiency of Fe₃O₄. The X-ray diffraction (XRD) measurements revealed that the samples had an inverse spinel cubic structure with an average crystallite size of 14.7-19.9 nm. The magnetic characteristics of nanoparticles show saturation magnetization are 55 emu/g for 10 mL and 38 emu/g for 20 mL MO extract solution variation. The temperature rise profile formed by nanoparticles had the maximum specific absorption rate (SAR) value of 2.54 W/g at a frequency of 20 kHz and an alternating field amplitude of 100 Oe for 10 mL MO extract solution variation and minimum value of 0.4 W/g at a frequency of 10 kHz and an alternating field amplitude of 100 Oe for 20 mL MO extract solution variation. According to the results, green synthesized Fe₃O₄ nanoparticles using MO have the promising in future to be a magnetic hyperthermia agent.

Abstract: Plant-mediated synthesis of nanoparticles has already gained recognition as an efficient, environmentally friendly method due to its non-toxicity, low cost, and simple process. In this study, we have successfully fabricated Fe₃O₄/mesoporous silica nanoparticles (MSN) via green synthesis utilizing Moringa oleifera (MO) extract. X-ray diffraction analysis (XRD), Fourier transforms infrared (FTIR), and ultraviolet-visible spectroscopy (UV-Vis) were used to investigate the microstructural and optical characteristics of the green synthesized Fe₃O₄/MSN. Fe₃O₄ and Fe₃O₄/MSN exhibit crystalline sharp peaks in their XRD patterns, whereas MSN has an amorphous structure. The crystallite size of Fe₃O₄ nanoparticles decreased after adding the MSN. FTIR spectra verified the existence of the C-C aromatics ring, Fe-O vibration mode of Fe₃O₄, and Si-O-Si stretching vibration, indicating that the green synthesized Fe₃O₄/MSN had been successfully obtained. After adding MSN, the UV-Vis absorbance spectra of Fe₃O₄ changed toward a lower wavelength, indicating that the electronic structure had changed, as revealed by the band gap energy decrease from 2.76 to 2.68 eV. Furthermore, these results proved that the surface modification using MSN on Fe₃O₄ via green route using MO extract could control their microstructural and optical properties, indicating the green synthesized Fe₃O₄/MSN had potential for future applications.

Abstract: The performance of a commercial GMR with a double-chip configuration has been investigated for detecting nanotag. Fe₃O₄ magnetic nanoparticles (MNPs) as tags were synthesized by co-precipitation method based on green synthesis using Moringa oleifera (MO) extract. Fe₃O₄ showed a soft ferromagnetic material and a magnetic saturation of 55.0 emu/g. MNPs-ethanol solution are dropped onto the surface of each chip of the sensing element. As a comparison, the performance of a single-chip configuration is also investigated. Obtained bias magnetic field used as a magnetic field sensing double-chip sensor is 3.8 Oe smaller than the single-chip sensor, which is 4.3 Oe, confirmed by the shift in the value of the first derivative order. Configuration of double-chip sensor in detecting Fe₃O₄ has a smaller LoD of 2.4 mg/mL compared to the single-chip configuration of 3.8 mg/mL. Therefore, Green-synthesized Fe₃O₄ as biocompatible magnetic tags in combination with commercial GMR sensors using double-chip configuration is promising for magnetic-based biosensor applications in driving more responsive detection and enabling portability by using a smaller energy source.

Abstract: The magnetite (Fe₃O₄) nanoparticles have been green-synthesized using Moringa Oleifera extract (MO) with variations of 5, 10, 15, and 20 ml. The X-ray diffraction results confirmed that the microstructure of Fe₃O₄ nanoparticles is a cubic inverse spinel structure with an average particle size of 5.0-8.9 nm and lattice parameters in the range of 8.14-8.22 Å. The results of UV-VIS data presented that the absorption edges of Fe₃O₄ MO 5 ml were 193.4 nm and the band gap energy of Fe₃O₄-MO is in the range of 2.62-3.31 eV. Dielectric properties were measured using impedance spectroscopy in the frequency range of 10-900 kHz. The results of measurement were in the form of real dielectric (ε'), imaginary dielectric (ε''), and tangent loss (tan δ). The dielectric constant decreased with increasing frequency due to interfacial polarization. In addition, MO affected the dielectric properties of Fe₃O₄ nanoparticles. The dielectrics of green-synthesized Fe₃O₄ with various MO of 5, 10, 15, and 20 ml at a frequency of 10 kHz are 248.5, 276.9, 289.0, and 308.1, respectively. The results measurement of the dielectric properties showed the optimality of the green synthesized sample with MO concentrations of 10 and 15 ml with values ​​of 276.9 and 289.0 at a frequency of 10 kHz. So, green synthesis Fe₃O₄ magnetite nanoparticles are used for Surface Plasmon Resonance (SPR) and Electromagnetic Interference (EMI) Shielding because these two applications are dependent on frequency and dielectric constant.

Abstract: Magnetic nanoparticles (Fe₃O₄) have considerable attention in various biomedical applications such as biosensors, drug delivery systems in the body, magnetic resonance imaging (MRI), and hyperthermia therapy. Hyperthermia therapy uses heat controlled by applied AC (Alternating Current) magnetic to kill cancer cells. This research aims to determine the effect of changes in temperature caused by the AC magnetic field on the varied magnetic nanoparticle solution. The Synthesize of Fe₃O₄ used the coprecipitation method to produce Fe₃O₄ nanoparticles. Mass of Fe₃O₄ nanoparticles varied of 95 mg and 125 mg. Nanoparticles physical properties were characterized using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and vibrating sample magnetometer (VSM). XRD profiles indicated that magnetic (Fe₃O₄) nanoparticles were successfully synthesized with a crystal size of 7.76 nm. SEM characterization of Fe₃O₄ nanoparticles was carried out at a magnification of 150.000 times and the average diameter of Fe₃O₄ powder nanoparticles was 20 nm. The temperature change measurement was performed using an AC magnetic field of 2.8 mT and frequency of 343 Hz, and time recorded changes temperature in 660 seconds. The temperature changes for solution concentrations of 95 mg and 125 mg were 7.7°C and 9.8°C, respectively. the concentration of solutions affects the value of the Specific Absorption Rate (SAR). The SAR values of each concentration of Fe₃O₄ solution were 0,0069 W/g and 0.0096 W/g. It proves that Fe₃O₃ prepared by coprecipitation method has potential for hyperthermia therapy application.

Abstract: In this work, a diagnostic application was performed by utilizing magnetic nanoparticles for the bio-sensing. A novel Fe₃O₄ nanostructure was synthesized in this paper using a simple hydrothermal method, the Fe₃O₄ nanoparticles are successfully controlled to provide a more dynamic site for catalytic reaction. FTIR-analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD) was used to examine the morphology of the synthesized nanoparticles. The findings showed that a unique Fe₃O₄ nanostructure was obtained nanoparticles confined in nanosphere. The relative catalytic kinetics of Fe₃O₄ nanostructure has followed Michaelis–Menten behaviours, according to an analysis of peroxidase-like activity. An effective approach for colorimetric sensing of glucose was formulated on the bases of efficient peroxidase-mimicking activity of Fe₃O₄ nanoparticles. The synthesized Fe₃O₄ nanoparticles are very hopeful for the application of bio-sensors.

Abstract: The functional magnetite nanoparticles are one of the most important functional materials for nucleic acid separation. Cell lysis and magnetic separation are two essential steps involve in optimizing nucleic acid extraction using the magnetic beads method. Many coating materials, coupling agents, chemical cell lysis, and several methods have been proposed to produce the specific desired properties for nucleic acid extraction. The important properties, such as biocompatibility, stability, linking ability, hydrophobicity, and biodegradable, were considered. The appropriate coating material of magnetite core and coupling agent are necessary to give biomolecules a possibility to link with each other through chemical conjugation. In this review, progress in functional magnetite nanoparticles to optimize the high binding performance in nucleic acid extraction is discussed.