Vibrating Sample Magnetometer Research Articles

Magnetic yolk-shell structured periodic mesoporous organosilica supported palladium as a powerful and highly recoverable nanocatalyst for the reduction of nitrobenzenes

A novel palladium-loaded yolk-shell structured nanomaterial with magnetite core and phenylene-based periodic mesoporous organosilica (PMO) shell (Fe3O4@YS-Ph-PMO/Pd) nanocatalyst was synthesized for the reduction of nitrobenzenes. The Fe3O4@YS-Ph-PMO/Pd was prepared through cetyltrimethylammonium bromide (CTAB) directed condensation of 1,4-bis(triethoxysilyl)benzene (BTEB) around Fe3O4@silica nanoparticles followed by treatment with palladium acetate. This nanocatalyst was characterized by using Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), low-angle and wide-angle powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) analyses. These analyses showed a magnetic nanomaterial with high chemical and thermal stability for the designed composite. The Fe3O4@YS-Ph-PMO/Pd nanocomposite was employed as a powerful and highly recoverable catalyst in the green reduction of nitroarenes in H2O at room temperature. A variety of nitroarene derivatives were applied as substrate in the presence of 0.9 mol% of Fe3O4@YS-Ph-PMO/Pd catalyst. All nitroarenes were selectively converted to their corresponding amines with high to excellent yields (92–96%) within short reaction times (10–18 min). This catalyst was recovered and reused at least 11 times without significant decrease in efficiency and stability.

Sono-assisted Adsorption of Methyl Violet 2B Using a Magnetic Kaolin/TiO2/γ-Fe2O3 Nano Composite

In this study, the efficacy of sono-assisted adsorption for the removal of methyl violet 2B (MV-2B) was investigated. A magnetic adsorbent was synthesized using kaolin and TiO2, designated as KTF. Various analyses including scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Zeta potential and vibrating sample magnetometer (VSM) were conducted to characterize the structure of KTF. The BET surface area and pore volume of KTF were determined to be 65.279 m2/g and 0.072 cm3/g, respectively. VSM analysis confirmed the superparamagnetic property of KTF. The effect of contact time, initial MV-2B concentration, KTF amount, temperature, ionic strength and initial pH of the solution on the sono-assisted adsorption of MV-2B was investigated. Sono-assisted removal of MV-2B was achieved at a rate of 85.6% under optimal conditions: original pH, KTF amount of 0.2 g/100 mL, initial MV-2B concentration of 20 mg/L, contact time of 15 min, and temperature of 22 °C. Conversely, lower removal efficiencies were observed with conventional adsorption methods employing shaking (37%) and stirring (60.5%). The kinetics of sono-assisted MV-2B removal followed a pseudo-second order model, while the Freundlich isotherm model exhibited a superior fit (R2 = 0.985) in describing the equilibrium behavior compared to Langmuir and Temkin models.

Hydrothermal synthesis of carbon dots incorporated in magnetite iron oxide nanoparticles for potential targeted brain cancer therapy: In-Vitro study

Surface modification of magnetite (Fe3O4) nanoparticles (NPs) using carbon dots (CDs) is a promising approach in biomedical applications due to excellent biocompatibility. Herein, the CDs were incorporated in the Fe3O4 NPs to observe the performance of CDs-Fe3O4 NPs for targeted brain cancer therapy. Scanning electron microscopy (SEM) images revealed the morphology of Fe3O4 NPs is rough and agglomerated. X-ray diffraction (XRD) diffraction pattern exhibits that the CDs are successfully incorporated in Fe3O4 NPs. Furthermore, magnetic properties evaluated using vibrating sample magnetometer (VSM) exhibited significant magnetization (51.362 emu/g) attributed to the greater occupancy of Fe+2 ions in the crystal lattice. XRD pattern confirmed the formation of NPs. Furthermore, functional groups of the NPs were validated through Fourier-transform infrared spectroscopy (FT-IR). The measurement of zeta potential affirmed the stability of the as-prepared Fe3O4 NPs, CDs, and CDs-Fe3O4 NPs, indicating a value of −7.64 mV, −0.5754 mV and −3.881 mV, respectively. Fe3O4 NPs exhibited a surface area of 58.6 m2/g as determined by Brunauer-Emmett-Teller (BET) analysis. The anticancer activity of the synthesized CDs-Fe3O4 NPs demonstrated inhibition against MG-U87 cells. Therefore, the synthesized CDs-Fe3O4 NPs hold potential for application in brain cancer therapy. In addition, CDs-Fe3O4 NPs exhibited exceptional biocompatibility and low cytotoxicity against osteoblast cells, establishing them as a safe biomaterial for biomedical applications.

Design and development of a first order reversal curve measurement enabled variable temperature vibrating sample magnetometer

In this paper we present the design, construction and calibration of a sensitive vibrating sample magnetometer (VSM) and temperature variable setup with a capability to measure magnetization of magnetic materials from 100 K to 400 K with First Order Reversal Curve (FORC) measurement facility. It uses a bipolar power supply to energize an electromagnet capable of attaining ±1 Tesla field, subwoofer speaker for vibrating the sample and the induced voltage in four coil setup is measured by a lock-in amplifier. All hardware is controlled by a customized LabView program. The cryostat is designed such that the temperature can be varied continuously from 100 K to 400 K using liquid nitrogen up to room temperature and forced nitrogen gas/air for high temperatures study. We report here the VSM sensitivity of up to 10−2 emu/gm and can measure much weaker signals. The FORC protocol in this system is implemented via a dedicated virtual instrument in LabView capable of magnetic field reversal and termination at appropriate point to study domain nucleation field. The detailed analysis of the data is done using the open-source resources. We present the FORC measurement for Co0.5Zn0.5Fe2O4, a ferrimagnet. To establish the sensitivity of the instrument we present the results of magnetization measurement with temperature and phase transition study of La0.4Ca0.6MnO3 and La0.75Sr0.25MnO3.

Design and development of a first order reversal curve measurement enabled variable temperature vibrating sample magnetometer

In this paper we present the design, construction and calibration of a sensitive vibrating sample magnetometer (VSM) and temperature variable setup with a capability to measure magnetization of magnetic materials from 100 K to 400 K with First Order Reversal Curve (FORC) measurement facility. It uses a bipolar power supply to energize an electromagnet capable of attaining ±1 Tesla field, subwoofer speaker for vibrating the sample and the induced voltage in four coil setup is measured by a lock-in amplifier. All hardware is controlled by a customized LabView program. The cryostat is designed such that the temperature can be varied continuously from 100 K to 400 K using liquid nitrogen up to room temperature and forced nitrogen gas/air for high temperatures study. We report here the VSM sensitivity of up to 10−2 emu/gm and can measure much weaker signals. The FORC protocol in this system is implemented via a dedicated virtual instrument in LabView capable of magnetic field reversal and termination at appropriate point to study domain nucleation field. The detailed analysis of the data is done using the open-source resources. We present the FORC measurement for Co0.5Zn0.5Fe2O4, a ferrimagnet. To establish the sensitivity of the instrument we present the results of magnetization measurement with temperature and phase transition study of La0.4Ca0.6MnO3 and La0.75Sr0.25MnO3.

Magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 spinel ferrites and their correlation with crystallite size

This study investigates the magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 (y = 0.0, 0.02, 0.04, 0.06, and 0.08) spinel ferrites (SFs) and their correlation with crystallite size. The synthesis was achieved using a sol-gel auto-combustion (SGAC) route and performed different characterizations, including X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray (EDX), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), and vibrating sample magnetometer (VSM) analysis. The cubic spinel phase was verified via XRD in pure NCF and Ho3+ doped NCF samples. The lattice constant (a) was improved from 8.344 Å to 8.378 Å. The substitution of Ho3+ ions led to a decrease in porosity from 42.22 % to 39.54 %. The introduction of Ho3+ ions also reduced the crystallite size (D) from 37.05 nm to 27.72 nm. The specific surface area (S) was increased from 27.44 g/cm2 to 36.14 g/cm2 with the doping of Ho3+. The average particle size (DS) was decreased from 54 nm to 35 nm. The EDX and ICP-AES analyses confirmed the good agreement with the theoretical composition. The VSM measurements provided insights into their magnetic properties. Furthermore, the doping of Ho3+ ions enhanced coercivity (HC), while reducing saturation magnetization (MS) from 64.35 emu/g to 16.22 emu/g. The decrease in crystalline anisotropy (K) observed at higher concentrations of Ho3+ may result from the increase in coercivity, potentially attributable to the smaller crystallite size of the single-domain SFs particles. The single-phase matrix and their magnetic behaviour showed that the Ho3+ doped Ni–Cu SFs samples are suitable for high-frequency applications.

Impact of incremental zinc-oxide incorporation on optical, magnetic, mechanical and photon transmission properties of K2O, SrF2, PbO containing borate-glasses

This study examines the radiation shielding properties of borate glass systems, with a focus on the simultaneous enhancement of optical, mechanical, and magnetic characteristics. The glass composition is represented by formula (55-x)B2O3+25PbO+10SrF2+10K2O + xZnO (where x: 0.0–10.0 mol%). By manipulating the ZnO concentration, we aimed to investigate its role as a radiation attenuator and its effects on the glass's optical, mechanical, and magnetic properties. Using traditional melt-quenching techniques, we produced the glass samples and examined their density, molar volume, linear attenuation coefficients (GLAC), mean free paths (GMFP), half-value layers (GHVL), and optical and magnetic properties. Our findings demonstrate that higher ZnO concentrations lead to a significant increase in density and a corresponding decrease in molar volume, thereby enhancing the glasses' ability to shield against gamma radiation. The radiation attenuation analysis revealed that increasing ZnO content substantially improves GLAC values across the energy range of 356–1333 keV. Additionally, ZnO incorporation decreases the optical bandgap, shifting the UV absorption edge to shorter wavelengths and enhancing UV dielectric capacity. Magnetic properties were assessed using vibrating sample magnetometer (VSM) measurements, showing a strong correlation between ZnO content and the effective atomic number (Zeff). It can be concluded that ZnO not only contributes to radiation shielding but also modifies the electronic structure of the glass, impacting its optical absorption properties.

FeCo@hydrochar nanocomposites as efficient peroxymonosulfate activator for organic pollutant degradation.

Sulfate radical-based advanced oxidation processes (SR-AOPs) are renowned for their exceptional capacity to degrade refractory organic pollutants due to their wide applicability, cost-effectiveness, and swift mineralization and oxidation rates. The primary sources of radicals in AOPs are persulfate (PS) and peroxymonosulfate (PMS) ions, sparking significant interest in their mechanistic and catalytic aspects. To develop a novel nanocatalyst for SR-AOPs, particularly for PMS activation, we synthesized carbon-coated FeCo nanoparticles (NPs) using solvothermal methods based on the polyol approach. Various synthesis conditions were investigated, and the NPs were thoroughly characterized regarding their structure, morphology, magnetic properties, and catalytic efficiency. The FeCo phase was primarily obtained at [OH-] / [Metal] = 26 and [Fe] / [Co] = 2 ratios. Moreover, as the [Fe]/[Co] ratio increased, the degree of xylose carbonization to form a carbon coating (hydrochar) on the NPs also increased. The NPs exhibited a spherical morphology with agglomerates of varying sizes. Vibrating-sample magnetometer analysis (VSM) indicated that a higher proportion of iron resulted in NPs with higher saturation magnetization (up to 167.8 emu g-1), attributed to a larger proportion of FeCo bcc phase in the nanocomposite. The best catalytic conditions for degrading 100ppm Rhodamine B (RhB) included 0.05g L-1 of NPs, 2mM PMS, pH 7.0, and a 20-min reaction at 25°C. Notably, singlet oxygen was the predominant specie formed in the experiments in the SR-AOP, followed by sulfate and hydroxyl radicals. The catalyst could be reused for up to five cycles, retaining over 98% RhB degradation, albeit with increased metal leaching. Even in the first use, dissolved Fe and Co concentrations were 0.8 ± 0.3 and 4.0 ± 0.5mg L-1, respectively. The FeCo catalyst proved to be effective in dye degradation and offers the potential for further refinement to minimize Co2+ leaching.

Graphene-based Sm-doped Co-ferrite for environmental applications

A graphene-based Sm-doped Co-ferrite CoSmFe-G nanosample was created using the citrate auto-combustion method. It acts as an antibacterial agent and heavy metal remover. The sample’s physical properties were analyzed using various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (FE-SEM), zeta potential, and vibrating sample magnetometer (VSM) measurements. The XRD results confirmed the presence of a single-phase cubic spinel structure. The experimental results indicated that doping with graphene and samarium significantly altered the magnetic properties of CoSmFe-G nanoparticles, reducing the saturation magnetization (MS) values to 35.759 emu/g. The sample showed antibacterial properties against both gram-positive and gram-negative bacteria, with inhibition zones measuring 12–14.5 mm in diameter. Additionally, the sample exhibited efficient (Pb2+) adsorption, with a maximum removal capacity of 99.8% and a multilayer adsorption mechanism indicated by the pseudo-second-order isotherm and Freundlich model matching. The study explores the binding interactions for lead removal and highlights the potential of using graphene-based Sm-doped Co-ferrite (CoSmFe-G) nano samples as a bio-adsorbent and antibacterial agent. This could lead to practical and efficient solutions for water disinfection.

Harnessing chemical functionality of xylan hemicellulose towards carbohydrate polymer-based pH/magnetic dual-responsive nanocomposite hydrogel for drug delivery

This study reports a pH/magnetic dual-responsive hemicellulose-based nanocomposite hydrogel with nearly 100 % carbohydrate polymer-based and biodegradable polymer compositions for drug delivery. We synthesized pure Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) using a co-precipitation method, then engineering xylan hemicellulose (XH), acrylic acid, poly(ethylene glycol) diacrylate, and Fe3O4 to synthesize the pH/magnetic dual-responsive hydrogel (Fe3O4@XH-Gel), through graft polymerization on XH with in-situ doping Fe3O4 MNPs initiated by the ammonium persulfate/tetramethylethylenediamine redox system. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectrometer (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), swelling gravimetric analysis, vibrating sample magnetometer (VSM) were employed to analyze the hydrogel's chemical structures, morphologies, pH-responsive behaviors, and magnetic responsiveness characteristics, mechanical and rheological properties, as well as cytotoxicity and biodegradability. The results indicate that the Fe3O4@XH-Gel exhibited excellent dual responsiveness to pH and magnetism. Furthermore, an emphasis was placed on the in-depth analysis of the pH response mechanism. Finally, we utilized this cutting-edge hydrogel to investigate the controlled-release behavior of two model drugs, Acetylsalicylic acid and Theophylline. The hydrogel demonstrated exceptional controlled release attributes, positioning it as a potential carrier for targeted drug delivery, particularly to the gastrointestinal conditions.

Physical properties of Pr3+ substituted zinc spinel (ZnPrxFe2−xO4) nanoferrites synthesized via sol–gel auto-combustion route

Spinel ferrites, a group of metal oxides, have garnered significant attention in the recent decade due to their high demand for numerous applications, including data storage and microwave device applications. In this context, we studied the effect of different doping concentrations of large Pr ions on the physicochemical properties of spinel lattice, such as dielectric and magnetic properties. In this research, we successfully fabricated a series of praseodymium ion-doped zinc spinel ferrites ZnPrxFe2-xO4 nanoparticles 0.00≤x≤0.20 via a simple and economical sol–gel auto-combustion approach. XRD (X-ray Diffraction Analysis) and FTIR investigations validate the presence of a cubical phase, with the crystallite size varying between 11 nm to 19 nm depending on the amount of Pr present. The Scherrer method, Williamson-Hall analysis (WH), and size-strain plot method (SSP) were investigated the correlation of crystalize size. The SSP approach has a better correlation coefficient than the WH method. Transmission electron microscopy TEM shows that the prepared material possessed the cubic and spherical symmetry. The significant variation in electrical parameters was discussed at an applied frequency ranging from 1 MHz to 3 GHz. The dielectric constant is approximately constant in low-frequency regions then relaxation peaks were observed at nearly 1.4 GHz and 2.2 GHz. The dielectric constant and complex dielectric constant of these samples dropped as the praseodymium content increased. Investigations regarding the magnetic properties were carried out using a vibrating sample magnetometer (VSM) at −23 k Oe to +23 k Oe. Low coercivity and relaxation peaks at high frequencies suggest that this material may be suitable for core materials, microwave technologies and recording media.

Magnetically recoverable CuFe2O4 nanocatalyst: Dual catalytic action in sonogashira and Chan-Lam coupling reactions

Magnetically retrievable CuFe2O4 nanocatalyst has been synthesized for Sonogashira (C-C) and Chan-Lam (C-N) coupling reactions by a facile co-precipitation method. Synthesized nanocatalyst was characterized by powder x-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analysis. The catalytic action of the catalyst was evaluated for both Pd-free C-C coupling and base-free C-N coupling reactions where an excellent product yield up to 96 % and 95 % respectively was obtained. The uniqueness of the catalyst was its effective performance under ambient reaction conditions in green solvents such as EtOH and EtOH:H2O (1:1) with a broad substrate scope. The catalyst can be easily retrieved from the reaction mixture with the aid of an external magnet and reused at least five times without significant loss in catalytic activity. The structural stability of the recovered catalyst was confirmed by XRD, FTIR, SEM and ICP-OES (Inductively coupled plasma - optical emission spectrometry) analysis. Thus, the synthesized catalyst works excellently well for dual applications and establishes the sustainable application of the catalyst.

Co3+ Doped CdFe2O4 Nanoparticles: Structural, Optical, Magnetic, and Electrical Properties

Through the citrate-gel auto-combustion technique, we synthesized Co-doped cadmium nano ferrites (NFs) with the formula CoxCd1−xFe2O4 (where 0 ≤ x ≤ 1.0 with increments of 0.2). The synthesized materials underwent comprehensive analysis utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy. Magnetic and electrical properties were evaluated using a vibrating sample magnetometer and LCR meter, respectively. XRD analysis confirmed the spinel phase structure and FD3M space group. SEM analysis revealed agglomerations of nanoparticles and grain boundaries. Elemental analysis of the synthesized nanomaterials was provided by energy dispersive spectroscopy. FTIR spectroscopy identified two main broad bands corresponding to the tetrahedral (A) and octahedral (B) sites, confirming the spinel structure. Magnetic properties such as magnetic saturation, coercivity, and remanent magnetization were characterized using VSM. Additionally, the LCR meter assessed frequency and temperature-dependent dielectric parameters, including AC conductivity (σAC), dielectric permittivity, dielectric loss (tan δ), and impedance spectra. An increase in AC conductivity (σAC) was observed with increasing temperature and frequency.

Magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 spinel ferrites and their correlation with crystallite size

This study investigates the magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 (y = 0.0, 0.02, 0.04, 0.06, and 0.08) spinel ferrites (SFs) and their correlation with crystallite size. The synthesis was achieved using a sol-gel auto-combustion (SGAC) route and performed different characterizations, including X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray (EDX), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), and vibrating sample magnetometer (VSM) analysis. The cubic spinel phase was verified via XRD in pure NCF and Ho3+ doped NCF samples. The lattice constant (a) was improved from 8.344 Å to 8.378 Å. The substitution of Ho3+ ions led to a decrease in porosity from 42.22% to 39.54%. The introduction of Ho3+ ions also reduced the crystallite size (D) from 37.05 nm to 27.72 nm. The specific surface area (S) was increased from 27.44 g/cm2 to 36.14 g/cm2 with the doping of Ho3+. The average particle size (DS) was decreased from 54 nm to 35 nm. The EDX and ICP-AES analyses confirmed the good agreement with the theoretical composition. The VSM measurements provided insights into their magnetic properties. Furthermore, the doping of Ho3+ ions enhanced coercivity (HC), while reducing saturation magnetization (MS) from 64.35 emu/g to 16.22 emu/g. The decrease in crystalline anisotropy (K) observed at higher concentrations of Ho3+ may result from the increase in coercivity, potentially attributable to the smaller crystallite size of the single-domain SFs particles. The single-phase matrix and their magnetic behaviour showed that the Ho3+ doped Ni-Cu SFs samples are suitable for high-frequency applications.

Magnetic covalent organic framework with ionic tags as an efficient catalyst in the preparation of 2,3-disubstituted thiazolidine-4-ones and N‑amino-2-pyridones

The functionalization of magnetic nanoparticles with covalent organic frameworks (COFs) will endow them inspiring characteristics. Herein, a new magnetic covalent organic framework (MCOF) decorated with trifluoroacetate as ionic sections (Fe3O4@COF-TFA) was designed and constructed. To confirm the successful synthesis of this hybrid material, several techniques including Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy(EDS), elemental mapping, transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM) and X-ray diffraction analysis (XRD) were applied. TGA/DTG analyses show that Fe3O4@COF-TFA has an excellent thermal stability up to 450 ℃. The FE-SEM analysis revealed that catalyst has the island-like morphology and according to TEM analysis, it has spherical geometry with nanometer scale particle size. Also, surface area of Fe3O4@COF and Fe3O4@COF-TFA are 74 and 12 m2.g−1, respectively. Fe3O4@COF-TFA was applied as a recoverable heterogeneous catalyst for construction of 2,3-disubstituted thiazolidine-4-ones and N‑amino-2-pyridones via a multi-component synthetic strategy. It is worth mentioning that synthesized derivatives have a good yield and short reaction times.

Synthesis and Characterization of Perovskite Manganate Based on La0.7Ca0.3MnO3 with Ni and Ti doping as Microwave Absorber Material

Research has been carried out on the effect of Ni and Ti doping on the microwave absorption properties of the perovskite manganate material La0.7Ca0.3Mn1-xNix/2Tix/2O3 (LCMNTO) with variations x = 0; 0.03; 0.05; and 0.1, which were synthesized by the sol-gel method. The effect of Ni and Ti doping on the structure, grain size, magnetic properties, and microwave absorption properties were investigated in detail by various analytical methods. XRD (x-ray diffraction) characterization showed that the material La0.7Ca0.3Mn1-xNix/2Tix/2O3 has a single phase with an orthorhombic crystal system. The SEM (scanning electron microscope) results showed a tendency to decrease in grain size when the composition of Ni and Ti dopants began to increase. VSM (vibrating sample magnetometer) characterization shows that La0.7Ca0.3Mn1-xNix/2Tix/2O3 is a soft magnet with magnetic properties that decrease with increasing Ni and Ti dopant composition. The characterization of VNA (vector network analyzer) in the 8-12 GHz shows that the highest ability to absorb microwaves is 98% at 8.24 GHz, and there is an addition of absorption areas point and widening of the absorption bandwidth. Thus, the material La0.7Ca0.3Mn1-xNix/2Tix/2O3 has the potential to become a microwave absorber material.

Tuning of structural, magnetic, and optical properties of ZnO nanoparticles by Co and Cu doping

Undoped, Cu, and Co-doped ZnO nanoparticles were synthesized by a simple co-precipitation method. We studied the structural, chemical, magnetic, and optical properties of synthesized nanoparticles by using X-ray Diffraction, Fourier Transform Infrared, Scanning Electron Microscopy, Vibrating-Sample Magnetometer, and UV–VIS spectroscopy. The X-ray Diffraction analysis discovers the crystalline hexagonal wurtzite structure and confirms the incorporation of Cu2+ and Co2+ in the ZnO lattice. The SEM photographs show that the nanoparticles are agglomerated, and the grain size of pure ZnO is decreased upon doping, showing inhibition of grain growth through doping. From VSM the coercivity and saturation magnetization of Co-doped (0.0189 emu/g and 84.044Oe) is higher as compared to pure and Cu-doped ZnO. The energy gap of doped and un-doped nanoparticles determined from the absorption spectrum indicates that it increases by doping of Copper and cobalt.

Effects of cooling rate upon annealing on the microstructure and properties of the FeCo49V2Nb0.2 alloy

In this paper, the influence of heat treatment on the magnetic properties of permendur the FeCo49V2Nb0.2 alloy used as the rotor core of a generator is investigated. The as-cast alloy is forged, hot and cold rolled to a thickness of 0.2 mm. The alloy samples were annealed in an argon gas furnace at different cooling rates. The results of measuring properties using the vibrating sample magnetometer method and measuring hardness show that the cooling rate has a significant impact on the properties of the FeCo49V2Nb0.2 alloy. Combining X-ray diffraction analysis and microstructure analysis allows us to explain the changes in properties obtained. From the results obtained, a conclusion can be drawn about the appropriate cooling rate for this alloy to achieve the best magnetic properties.

Optimization of the coating process in the PEGylated chitosan-based doped cobalt ferrite nanoparticles for hyperthermia applications using the Taguchi method

In this study, the parameters of coating process in the PEGylated chitosan-based doped cobalt ferrite nanoparticles for hyperthermia applications was optimized using the Taguchi method. The effect of chitosan and polyethylene glycol as well as the glutaraldehyde (crosslinker) contents on the structural, microstructural, and magnetic properties and the colloidal stability of the nanoparticles were investigated. Ultimately, to optimize the properties of the nanoparticles, the Taguchi method (L16 orthogonal array) was employed. The incorporation of the Ca2+ and Gd3+ into the spinel structure with an average crystallite size of 21 nm was successfully verified by X-ray diffraction (XRD) and the Rietveld refinement analysis. Moreover, thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy (FT-IR) demonstrated the effective functionalization of the chitosan and polyethylene glycol coatings. Vibrating sample magnetometer (VSM) measurements revealed that saturation magnetization (Ms) was achieved in the range of 54.91–60.42 emu/g. Also, microstructural observations indicated that the coating layer can affect the particle size distribution and morphology. The Taguchi method identified that the glutaraldehyde content is the most expressive parameter influencing the nanoparticles’ properties, with the optimum properties achieved at chitosan, polyethylene glycol, and glutaraldehyde of 0.4 g, 0.08 g, and 1.2 ml, respectively. The antibacterial analysis confirmed the promising potential of the coated nanoparticles for biomedical applications. Furthermore, the magnetic heating efficiency of the synthesized nanoparticles was investigated in various concentrations of magnetic fluid, demonstrating their suitability for magnetic hyperthermia application.

Magnetic carboxymethyl gond katira-grafted-poly(3-aminobenzoic acid) as an antibacterial biosorbent for purification of acetamiprid-contaminated water

The elimination of pesticides from polluted water is critical due to their harmful environmental and biological impacts. Recently, there has been interest in utilizing natural polymer-based adsorbents as an eco-friendly approach to eliminate or reduce the levels of water pollutants. In this work, we synthesized an antimicrobial and magnetic bionanocomposite consisting of carboxymethyl gond katira-grafted- poly(3-aminobenzoic acid) with iron oxide and zinc oxide NPs (CMT-g-P3ABA/ZnO/Fe3O4) through an in situ polymerization reaction and examined for its ability to adsorb the pesticide acetamiprid (AP). The bionanocomposite was characterized using several analytical techniques, including spectroscopy; XRD presented the crystalline structure of ZnO/Fe3O4 in the CMT-g-P3ABA amorphous matrix. The ZnO/Fe3O4 partially aggregated formation and exhibited polyhedral crystal shapes was depicted by electron microscopy images, vibrating sample magnetometer (45.06 emu/g), porosimetry (5.52 m2/g), and thermal (Chair yield of approximately 43.83 %) and elemental analyses. Under various conditions, including solution pH (4–9), adsorbent dosage (0.005–0.025 g), time of contact (10–30 min), and pesticide preliminary concentration (200–400 mg/L) in 10 mL of the solution. Based on this research, Adsorption data were perfectly fitted by the Freundlich isotherm model with RAP2= 0.99038, while the pseudo-second-order (PSO) model well-explained adsorption kinetics with RAP2= 0.99847. AP adsorption to the CMT-g-P3ABA/ZnO/Fe3O4 bionanocomposite was successful due to hydrophobic interactions, hydrogen bonding, and π-π stacking. Furthermore, adsorption-desorption experiments demonstrated that the bionanocomposite could be regenerated after three reuse cycles without considerable loss of pesticide removal performance. The bionanocomposite also exhibited promising antimicrobial activity in contradiction to test bacteria.