Vibrating Sample Magnetometry Research Articles

How magnetism-based fractional spinels contribute to the bioavailability of geogenic chromium in serpentine soils of Taiwan

Serpentine soils are highly rich in geogenic chromium (Cr), typically associated with spinel minerals. The high resistance of these minerals to weathering has raised concerns regarding their contribution to Cr bioavailability in serpentine soils. This study collected soil horizon samples from two pedons (Entisol and Ultisol) in eastern Taiwan and applied a two-step magnetic separation method to divide the bulk soils into strongly magnetic (SM), weakly magnetic (WM), and nonmagnetic (NM) fractions. The basic characteristics of the bulk soils were examined. To characterize the mineralogy and geochemistry of the fractions and determine their quantitative contribution of bioavailable Cr in serpentine soils, we analyzed their mineral composition, magnetic properties, and elemental composition and valence by using various spectrometric techniques, such as X-ray diffraction, electron probe microanalysis, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, as well as vibrating sample magnetometry. The results indicated the main Cr-bearing minerals were magnetite and chromite in the SM and WM fractions, with minor occurrences in layer silicates, such as serpentine and chlorite, in the NM fraction. The total Cr content decreased in the following order: SM > WM > NM. The SM fraction had the lowest weight proportion, and this proportion was lower for the Ultisol than the Entisol. This observation indicated that the weathering of Cr spinels is associated with the substantial cation substitution of Al, Ca, Mn, and Ni for Fe and Cr in broken mineral grains and increases in the Fe(III) and Cr(VI) concentrations in magnetite. The SM fraction, mainly consists of magnetite and chromite, exhibited the highest concentration of bioavailable Cr extracted by 0.1 M HCl. However, the Cr-bearing layer silicates represented the largest potential pool of bioavailable Cr in the bulk soils because the weight proportion of the NM fraction was higher than those of the other fractions and increased during pedogenesis.

Effect of 10 MeV electron irradiation on structural and magnetic properties of Ti- and Al- substituted strontium hexaferrite SrFe11.3Ti0.4Al0.3O19

The irradiation stability of Ti- and Al-substituted SrFe11.3Ti0.4Al0.3O19 strontium hexaferrite to 10 MeV electron irradiation with the fluences of 1014 and 2·1017 cm−2 was investigated using various characterization techniques such as scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectrum microanalysis, atomic force microscopy, Raman spectroscopy, vibrating sample magnetometry and magnetic force microscopy. Notable changes in lattice vibrations, magnetic domain microstructure and magnetization behavior were obtained after the electron irradiation with the fluence of 2·1017 cm−2. Phonon hardening observed by Raman spectroscopy confirms the increasing disorder in crystalline structure and the presence of spin-phonon coupling in the samples after electron irradiation with the fluence 2·1017 cm−2. It was found that the strongest spin-phonon interactions correspond to A1g vibration modes at trigonal bipyramidal 2b, 2a octahedral, 4f1 tetrahedral sites and E1g mode at 4f2 octahedral site in electron-irradiated SrFe11.3Ti0.4Al0.3O19 hexaferrite, while the most radiation-resistant phonon mode is A1g vibration of the Fe–O bonds at the 4f2 octahedral site. No significant change was observed in magnetic saturation magnitude after electron irradiation. The increase in coercivity and significant decrease of magnitude of the dM/dH derivative of magnetization curves with increasing radiation fluence is attributed to the increase in uniaxial magnetic-crystalline anisotropy. It is found that the fractal dimension of hierarchical magnetic domain structure in SrFe11.3Ti0.4Al0.3O19 continuously decreases with increasing fluence of 10 MeV electron irradiation, which can be caused by the distortion in uniaxial magnetocrystalline anisotropy and irradiation-induced defects.

Ferromagnetism in High Entropy Cantor alloy triggered and tuned by severe plastic deformation

The process of severe plastic deformation (SPD) introduces unique conditions to materials, leading to the emergence of novel properties. This research specifically investigates the observation of deformation-induced ferromagnetism resulting from SPD processing. High-pressure torsion (HPT) is utilized to process both single-phase and nanocomposite high entropy alloys (HEAs). Vibrating sample magnetometry (VSM) confirms that HPT processing triggers the development of ferromagnetic properties. The distribution and alignment of magnetic domains post-SPD treatment are further examined using differential phase contrast scanning transmission electron microscopy (DPC STEM). Atom probe tomography (APT) analysis suggests that this phenomenon stems from the localized enrichment of ferromagnetic elements, particularly Ni, induced by deformation. This observation underscores the ‘cocktail effect’ in HEAs, whereby interactions between different elements has led to this unique magnetic behavior. Additionally, deliberate mechanical mixing of the CoCrFeMnNi alloy with a HfNbTaTiZr HEA, comprising non-ferromagnetic constituents, introduces a large rotational strain that alters the ferromagnetic properties. This mixing facilitates a transition from a random orientation of magnetic domains, as seen in the HPT-processed single CoCrFeMnNi alloy, to a coordinated alignment within the nanocomposite HEA.

Cr–Sc co-substituted nickel-cobalt nanospinel ferrites: An investigation of their structural, magnetic properties and hyperfine interactions

The chromium and scandium co-substituted nickel-cobalt nanospinel ferrites (NSFs) having general formula of Co0.5Ni0.5ScxCrxFe2-2xO4 (CoNiScCr) (x ≤ 0.10) have been fabricated through the sol-gel route and citric acid as fuel and characterized by X-ray diffractometry (XRD), 57Fe Mössbauer spectroscopy, vibrating sample magnetometry (VSM), and finally by scanning and transmission electron microscopy techniques (SEM and TEM, respectively). The crystallite size (Dmax) values of the products were estimated to lay between 31 and 46 nm, which was calculated by the Scherrer formula. It was observed that the doping ions’ concentration did not have a linear impact on the expansion of the lattice constant. SEM and TEM present the cubic shape of CoNiScCr NSFs. All ratios demonstrate highly agglomerated cubic particles with diverse sizes. Both XRD and EDX (Energy Dispersive X-ray Spectroscopy) analyses confirmed the absence of any impurity/phases. Through an analysis of hysteresis loops at 300 (RT = room temperature) and 20 K, along with a probe of temperature-induced alteration in magnetization M, the magnetic properties of CoNiScCr (x ≤ 0.10) NSFs have been thoroughly investigated. Notably, all products exhibited complementary soft and hard magnetic behaviors at RT and 20 K, respectively. At 20 K, the observation of squareness ratio values surpassing 0.5 exhibits a single-domain behavior at this specific temperature. Magnetic parameters, in general, exhibit fluctuations with increasing doping content. Across the entire range of materials studied, a notable trend emerges as the temperature decreases, the magnetization in the zero field cooling curves shows a non-linear decrease, eventually stabilizing in the field cooling branches. The findings suggest that the inclusion of Sc3+/Cr3+ dopants can be utilized to manipulate and achieve desired magnetic properties in Co–Ni ferrites. The spectra of Mössbauer analysis, which was utilized to establish the distribution of cations, presented four magnetic sextets for all samples. Doped ions are substituted with Fe3+ ions at the B site.

Magnetic Nanoparticles with On-Site Azide and Alkyne Functionalized Polymer Coating in a Single Step through a Solvothermal Process.

Background/Objectives: Magnetic Fe3O4 nanoparticles (MNPs) are becoming more important every day. We prepared MNPs in a simple one-step reaction by following the solvothermal method, assisted by azide and alkyne functionalized polyethylene glycol (PEG400) polymers, as well as by PEG6000 and the polyol β-cyclodextrin (βCD), which played a crucial role as electrostatic stabilizers, providing polymeric/polyol coatings around the magnetic cores. Methods: The composition, morphology, and magnetic properties of the nanospheres were analyzed using Transmission Electron and Atomic Force Microscopies (TEM, AFM), Nuclear Magnetic Resonance (NMR), X-ray Diffraction Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), Matrix-Assisted Laser Desorption/Ionization (MALDI) and Vibrating Sample Magnetometry (VSM). Results: The obtained nanoparticles (@Fe3O4-PEGs and @Fe3O4-βCD) showed diameters between 90 and 250 nm, depending on the polymer used and the Fe3O4·6H2O precursor concentration, typically, 0.13 M at 200 °C and 24 h of reaction. MNPs exhibited superparamagnetism with high saturation mass magnetization at room temperature, reaching values of 59.9 emu/g (@Fe3O4-PEG6000), and no ferromagnetism. Likewise, they showed temperature elevation after applying an alternating magnetic field (AMF), obtaining Specific Absorption Rate (SAR) values of up to 51.87 ± 2.23 W/g for @Fe3O4-PEG6000. Additionally, the formed systems are susceptible to click chemistry, as was demonstrated in the case of the cannabidiol-propargyl derivative (CBD-Pro), which was synthesized and covalently attached to the azide functionalized surface of @Fe3O4-PEG400-N3. Prepared MNPs are highly dispersible in water, PBS, and citrate buffer, remaining in suspension for over 2 weeks, and non-toxic in the T84 human colon cancer cell line, Conclusions: indicating that they are ideal candidates for biomedical applications.

Инновационные магнитные наноматериалы для улучшения хранения энергии

Background: Finding effective energy storage technologies is crucial for transitioning to sustainable energy systems. Magnetic nanoparticles have emerged as options due to their distinctive magnetic characteristics, which can considerably improve the performance of energy storage systems. Objective: This research aims to investigate innovative magnetic nanoparticles and assess to increase the efficiency and capacity of energy storage systems. The emphasis is on developing materials with optimal magnetic characteristics and incorporating them into current energy storage methods. Methods: Co-precipitation and thermal breakdown were used to create a range of new magnetic nanomaterials. Vibrational sample magnetometry, X-ray diffraction, and cyclic voltammetry were used to determine these materials' magnetic characteristics, structural integrity, and electrochemical performance. Subsequent integration into supercapacitors and lithium-ion batteries was carried out to evaluate energy storage capacity. Results: The synthesized magnetic nanoparticles showed improved magnetic saturation and charge-discharge characteristics compared to standard materials. When used in supercapacitors, they increased capacitance by 20% and improved cycle stability by 25%. Similarly, these nanomaterials improved the energy density of lithium-ion batteries by 15% and increased their longevity by 30%. Conclusion: The unique magnetic nanoparticles created in this work significantly improve the performance of energy storage devices. The increased capacitance, energy density, and operational stability indicate that these materials for future energy storage applications. Further study is required to optimize these materials for commercial application and investigate their scalability and environmental effects.

Peculiarities of Hematite Reduction Using Waste Activated Sludge (WAS) Carbonization Products

In the present study, XRD, SEM/EDS, Raman, EMR/EPR spectroscopy, and vibrating sample magnetometry (VSM) were used to analyze the reduction of hematite by the carbonization products of waste activated sludge (WAS) at 500–1000 °C. The reduction process includes the following steps: α-Fe2O3 → Fe2O3 + Fe3O4 (Ttr~500 °C) → Fe3O4 (Ttr~600–700 °C) → FeO → Feamorph. (Ttr~1000 °C). The prevalence of certain phase compositions at different hematite reduction temperatures makes it possible to predict the areas viable for the application of reduced oxides: adsorbents (after Ttr~500 °C) → soft ferromagnetic materials (after Ttr~600–700 °C) → electrically engineered amorphous iron (after Ttr~1000 °C).

Martensitic transformations and magnetic properties of Ni50−xMn37Sn13Fex(x = 0.5, 1, 1.5) melt-spun ribbons

AbstractThe present study investigates the influence of iron (Fe) doping on the martensitic transformation and magnetic properties of Ni50−xMn37Sn13Fex(x = 0.5, 1, 1.5) magnetic shape memory alloys in ribbon form. The ribbons were prepared using arc-melting followed by melt-spinning processes and were characterized using X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and vibrating sample magnetometry. Our findings demonstrate that the addition of Fe shifts the martensitic transformation to lower temperatures and increases the Curie point of the austenitic phase, $$T_{c}^{\text A}$$ T c A , leading to an enhanced magnetism in the austenitic phase. Moreover, a significant increase in the magnetization jump $$(\Delta M)$$ ( Δ M ) is observed, from $$ 3.3\;{\text{emu\ g}}^{-1} $$ 3.3 emu\ g - 1 for $$x=1$$ x = 1 to $$17 \, {\text{emu\ g}}^{-1} $$ 17 emu\ g - 1 for $$x=1.5$$ x = 1.5 under a $$50 \, \text {Oe}$$ 50 Oe applied magnetic field. The structural transformations are also found to be sensitive to the external applied magnetic field. The isothermal magnetization curves exhibit the exchange bias effect, which confirms the coexistence of antiferromagnetic and ferromagnetic coupling in the samples. Furthermore, the exchange bias effect increases with the Fe content.

Sr doping effects on La(1-x)SrxMnO3-BaTiO3 nanocomposites: A comprehensive analysis of structural, optical, magnetic, and dielectric properties

Sol-gel synthesized La(1-x)SrxMnO3–BaTiO3 nanocomposites with varying strontium content were investigated to explore the influence of Sr doping on their properties. X-ray diffraction confirmed the perovskite phase purity. Sr doping resulted in a tunable bandgap, widening from 2.33 eV to 2.57 eV as Sr content increased, as revealed by Diffuse Reflectance Spectroscopy. Vibrating Sample Magnetometry measurements exhibited a Sr-dependent decrease in saturation magnetization (22 emu/g for x = 0.2 to 14 emu/g for x = 0.5). Dielectric analysis demonstrated an enhanced dielectric constant and the emergence of new relaxation behaviors with Sr doping. These findings unveil the tailorable optical, magnetic, and dielectric properties of LSMO-BTO nanocomposites due to Sr doping, suggesting their potential for diverse technological applications.

Optimizing BHF/PVDF Composites via Compression Molding for High-Frequency Applications and Electromagnetic Shielding

Electromagnetic interference (EMI) poses significant challenges to the reliable operation of communication systems, medical devices, and electronic equipment, often resulting in signal degradation, data loss, and equipment failure. To mitigate these issues, this study investigates the development of barium hexaferrite (BHF)/polyvinylidene fluoride (PVDF) composites, synthesized via compression molding, to optimize their electrical and magnetic properties for high-frequency EMI shielding applications. Through comprehensive characterization, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and vector network analysis (VNA), we demonstrate that increasing the BHF content within the composites enhances their complex permittivity, impedance matching, and attenuation coefficients, making them highly effective for EMI shielding. Notably, the composite containing 20 wt.% PVDF achieved a reflection loss (RL) of -42 dB at a thickness of 2 mm, indicating superior shielding effectiveness. These results underscore the potential of BHF/PVDF composites as a viable solution for advanced EMI suppression in high-frequency electronic and military applications, combining economic feasibility with robust performance.

Effects of a Novel Magnetic Nanomaterial on Oral Biofilms

Dental caries is one of the most common oral chronic infectious diseases, and novel antibacterial materials must be developed to control plaque and inhibit formation of dental caries. Combining magnetic nanomaterials with antibacterial agents to decrease the formation of bacterial biofilm has been a hot topic in the biomedical field. The present study developed a novel magnetic nanomaterial chemically combined with dimethylaminododecyl methacrylate (DMADDM) and initially investigated its inhibiting effects on biofilms by using traditional caries-related bacteria and saliva flora models. The novel magnetic nanomaterials successfully loaded DMADDM according to thermogravimetric analysis, Fourier transform infrared spectroscopy, x-ray diffraction, vibrating sample magnetometry, scanning electron microscopy, and transmission electron microscopy results. Further, the novel nanoparticle Fe3O4@SiO2@DMADDM with concentration of 8 mg/mL could effectively reduce Streptococcus mutans biofilm and decrease the production of lactic acid. The 16S rDNA sequencing revealed that Fe3O4@SiO2@DMADDM could depress the proportion of caries-related bacteria in saliva-derived biofilm, such as Streptococcus, Veillonella, and Neisseria. Therefore, Fe3O4@SiO2@DMADDM is a novel effective antibacterial magnetic nanomaterial and has clinical potential in plaque control and dental caries prevention.

Cr-doped CdS and ZnS nano/microstructures with ferromagnetic properties

Transition-metal-doped cadmium sulfide (CdS) and zinc sulfide (ZnS) dilute magnetic semiconductors have attracted widespread research interests due to their potential spin electron applications. Most theoretical and experimental analyses have focused on studying their optical properties. In response to the widespread application of dilute magnetic semiconductor nanomaterials in electronic components, semiconductor chips, integrated circuits and other fields, dilute magnetic semiconductors with room-temperature ferromagnetic chromium (Cr)-doped cadmium sulfide and zinc sulfide nanostructures were synthesized using the solvothermal method. According to X-ray diffraction analysis, the products of chromium-doped cadmium sulfide and zinc sulfide were clearly determined to be a hexagonal phase. Scanning electron microscopy images showed that the morphologies of cadmium sulfide and zinc sulfide with different contents of chromium were mainly composed of nanorods and a micro-floral shape. Energy-dispersive X-ray spectroscopy measurements indicated that the synthesized products were composed of chromium, cadmium (Cd), zinc (Zn) and sulfur (S). Vibrating-sample magnetometry showed that undoped cadmium sulfide exhibited weak ferromagnetism at room temperature, and undoped zinc sulfide exhibited diamagnetism, while chromium-doped cadmium sulfide and zinc sulfide had strong ferromagnetism. The saturation magnetization M s of chromium-doped cadmium sulfide (chromium = 4.21%) was about 9.524 × 10−3 emu/g; the coercivity H c was about 98.327 Oe. The saturation magnetization M s of chromium-doped zinc sulfide (chromium = 7.67%) was about 8.502 × 10−3 emu/g; the coercivity H c was about 96.237 Oe. The ferromagnetism of chromium-doped cadmium sulfide and zinc sulfide was attributed to the double-exchange mechanism.

Coating of Carbon Black (CB) and Graphene Oxides (GOs) with Magnetite (Fe3O4)

Composites containing iron oxides are obtained by the co-precipitation of iron(II) and iron(III) compounds in the presence of different substrates in an alkaline environment. Newly synthesized graphene oxide (GO), reduced graphene oxide (rCO) and carbon black (CB) are used as substrates. Methods of obtaining GO–amorphous iron compound, rGO–Fe3O4, and CB–Fe3O4 composites are developed. It is determined that rGO–Fe3O4 and CB–Fe3O4 magnetic composites can be obtained at 70–75°C, while in the presence of GO, a non-magnetic composite containing an amorphous iron compound is formed under the same conditions. This composite, when heated in vacuum at 170–175°C, undergoes exfoliation, in result of which a powder composite rGO–amorphous iron compound is formed, the volume of which is 2.7 times greater than that of initial powder. Partial reduction of the formed composite takes place at 550°C and rGO–Fe3O4 is obtained. Formation of the magnetite phase is determined by XRD (X-Ray Diffraction) analysis. The structural-morphological study of the synthesized composites is carried out by the SEM (Scanning Electron Microscopy) method. Their magnetic characteristics are studied using VSM (Vibrating Sample Magnetometry) method.

Synthesis of NiFe₂O₄ Magnetic Using Artocarpus altilis Leave Extract for Photocatalytic Degradation of Methylene Blue Dye and Antibacterial Applications

The green synthesis method is an economical and eco-friendly approach to synthesizing materials. This study effectively synthesized magnetic NiFe2O4 by Artocarpus altilis extract leave for the photocatalytic degradation of Methylene blue dye and exhibited antibacterial properties. The phytochemical compounds found in plants act as agents for reducing and stabilizing NiFe2O4. The synthesized NiFe2O4 was examined using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), and vibrating sample magnetometry (VSM). The variables in degradation include solution pH, dye concentration, catalyst dose, and irradiation time. The synthesized NiFe2O4 has a 12.4 nm crystallite size, a saturation magnetization (Ms) of 44.56 emu/g, and a band gap of 1.68 eV. The degradation efficiency of methylene blue dye was 98.2% under the following conditions: a solution pH of 10, a concentration of 10 mg/L, a dose of 0.1 g/L, and an irradiation time of 90 min. The degradation mechanism of Methylene blue dye may be accurately described by pseudo-first-order kinetics, with a kapp value of 0.0443 min-1. NiFe2O4 has high stability; after five degradation cycles, the degradation efficiency decreased by 4.45%. Additionally, NiFe2O4 demonstrates significant antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria.

Ni-Fe2O3@SiO2-Pr-DBU: A novel efficient magnetically retrievable catalyst for one-pot synthesis of dihydropyrano [3,2-c] chromene

In the present work, Ni-Fe2O3@SiO2-Pr-DBU was synthesized as a novel magnetically separable nano-catalyst and characterized by various techniques like Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Vibrating-sample magnetometry (VSM), Transmission electron microscopy (TEM) and Elemental analysis by energy dispersive X-ray (EDX). The catalytic efficiency of NiFe2O3@SiO2-Pr-DBU was explored in the synthesis of dihydropyrano[3,2-c] chromenes through a one-pot multicomponent reaction of 4-hydroxycoumarin, malononitrile, and aryl aldehydes in aqueous solution at ambient temperature condition. An external magnet easily removed the nano-sized magnetic core catalyst from the synthesized reaction mixture. It was recycled for five successive runs while maintaining its potential and adhering to our green synthesis approach. We used dihydropyrano chromene, a highly biologically active commercial compound, to prepare some novel derivatives.

Magnetic properties and microstructural of ion-implanted Gadolia doped Ceria-Barium monoferrite thin film deposited on Kapton for electromagnetic wave absorber application

Gadolia-doped Ceria-Barium Monoferrite (GDC-BaFe2O4) thin films have been deposited on Kapton sheets using the DC sputtering method as electromagnetic (EM) wave-absorbing materials. The present study has examined the structural, magnetic, and microwave absorption properties of GDC-BaFe2O4. The primary approaches used in this investigation included changing the surface form and applying EM wave-absorbing materials as surface coatings. X-ray diffraction research showed that the GDC-BaFe2O4 thin films have an orthorhombic crystal structure. The bonding investigation revealed the existence of Fe-O, Ce-O, and Ba-O-Ba functional groups at 426.87, 517.42 and 1014.84 cm−1, respectively. Vibrating-sample magnetometry confirmed that saturation magnetization decreased with increasing sputtering time and revealed the ferromagnetic behavior of the GDC-BaFe2O4 thin film. Ce, Gd, Ba, Fe, and O were evenly and similarly distributed over the Kapton surface of the GDC-BaFe2O4 thin films, according to energy-dispersive X-ray spectroscopy and scanning electron microscopy. Based on the atomic force microscopy test, the root-mean-square roughness (Rq) increased during the ion implantation procedure. With a 7.5-minute sputtering period, the microwave absorption ability reached a maximum reflection loss value of −39.6 dB (99.98 %) at 10 GHz. As a result of these findings, GDC-BaFe2O4 appears to be a promising candidate for EM wave absorption.

Tailoring structural and magnetic properties: Cd²⁺ and Cu²⁺ co-doped Ni-Zn ferrite nanoparticles via sol-gel auto-combustion

In this research work, we have incorporated paramagnetic Cu2+ and diamagnetic Cd2+ cations in spinel ferrites. By adjusting the concentrations of Cu2+ and Cd2+, it is possible to achieve a balance between enhanced electrical conductivity, desired magnetic properties, and suitable structural characteristics for applications in high-frequency devices, magnetic sensors, and electromagnetic interference (EMI) suppression through a synergistic effect. The sol-gel auto-combustion method was employed to synthesize Cd²⁺ and Cu²⁺ co-doped Ni0.5Zn0.5-x-yCuxCdyFe2O4 (x = y = 0.0, 0.05, 0.1, 0.15, 0.2) ferrite nanoparticles. Structural, morphological-compositional, functional, and magnetic properties of the nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The XRD results confirmed the single-phase spinel structures with lattice constants increasing with higher dopant concentrations. The average crystallite sizes were found in the range of 38.14 - 42.68 nm and lattice constants in the range of 8.389 - 8.423 Å. Morphological analysis revealed agglomeration, consistent with the stoichiometric proportions during synthesis. There is a decreasing trend in nanograin sizes in the range of 40 to 73 nm with the concentration. FT-IR spectra verified the spinel structures through characteristic absorption bands around 600 cm⁻¹ and 400 cm⁻¹. Magnetic measurements indicated a decrease in saturation magnetization with increasing dopant levels indicating their potential use in electromagnetic wave absorption and magnetic memory devices.

Silica/APTPOSS anchored on MnFe2O4 as an efficient nanomagnetic composite for the preparation of spiro-pyrano [2, 3-c] chromene derivatives

The synthesis of Octakis [3- (3-amino propyl triethoxysilane) propyl] octa-silsesquioxane (APTPOSS), a derivative of polyhedral oligomeric silsesquioxane, was utilized to produce an efficient nanocomposite. MNPs@Silica/APTPOSS was characterized through scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction, and Thermogravimetric analysis. These magnetic nanoparticles, a combination of organic-inorganic hybrid polyhedral oligomeric silsesquioxane, were utilized as a proficient heterogeneous catalyst in the one-pot synthesis of spirooxindoles derivatives. Furthermore, they could be swiftly isolated and reused six times while maintaining their catalytic efficiency.

Removal of Pb(II) pollution by algae-Fe-Ni magnetic nanocomposite

A magnetic nanocomposite material was synthesized by combining Chaetomorpha Algae with a Fe–Ni alloy. The dry algae, Fe, and Ni were mechanically alloyed using a ball milling technique in an argon atmosphere. The resulting Algae-Fe-Ni Magnetic Nanocomposite (AFNMN) was characterized using various analytical techniques, including particle size distribution (PSD) analysis, Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), vibrating sample magnetometry (VSM), atomic absorption spectroscopy (AAS), and Fourier transform infrared (FTIR) spectroscopy. Multiple isotherm models were employed to study the adsorption of Pb(II) ions onto the AFNMN material. Density functional theory (DFT) was applied to predict the most stable amino acids for the removal of Pb(II) pollutants from a set of 14 amino acids. To optimize the Pb(II) uptake performance, three key experimental parameters were fine-tuned: pH, temperature, and reactor vessel geometry. Four different optimization methods were utilized, including response surface methodology (RSM), fuzzy logic, adaptive network-based fuzzy inference system (ANFIS), and artificial neural network genetic algorithms (ANN-GA). Additionally, a heat transfer simulation was conducted to determine the optimal vessel positions for achieving the desired temperature variations within the reactor during the adsorption process.

Origami-based multifunctional sensing platform for sustainable detection of hazardous magnetic materials

Anthropogenic magnetite (AM) nanoparticles have been identified in the human brain and circulatory system, potentially linked to neurodegenerative and cardiovascular diseases. Specifically, AM and other magnetic nanocontaminants from industrial emissions and brake wear are hazardous components of particulate matter. Such contamination enriches urban soils with magnetite and other magnetic nanocontaminants, which can be absorbed by plants like rice and consequently enter the human body indirectly. Developing accurate and robust AM-sensing platforms is crucial, especially in areas where magnetic contamination threatens ecosystems and human health. Innovative materials, such as magnetoactive smart materials, are essential for creating sensors with specific, wireless, and adjustable magnetic properties for efficient detection and monitoring of soil contamination. This study presents an origami-based multifunctional sensing platform for sustainable detection of magnetic environmental contamination. Utilizing paper as its substrate for low-cost AM sensing, the device incorporates two wax/NdFeB magnets, four hydrophilic channels, and a hydrophilic analysis area, enclosed by hydrophobic wax. Through comprehensive analysis techniques including energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, infrared spectroscopy, and photographic color changes, the device exhibited a detection limit below 156 μg. The platform's versatility, affordability, sustainability, and capacity for multi-analysis indicate promising prospects for developing economically equitable, user-friendly, mechanically robust, and flexible magnetic contamination sensing devices. These devices eliminate the need for complex machinery while delivering rapid, accurate, and precise results tailored to diverse environmental needs, thus promoting sustainable and safe societies.