Vibrating Sample Magnetometer Measurements Research Articles

Magnetic Crosslinked Porcine Pancreatic Lipase Aggregates for Transesterification Process

Lipases have been used in industrial processes as biocatalysts for transesterification reactions. The synergism between enzymes and magnetic properties may be reached by using magnetic nanoparticles (MNPs) as support to immobilize them in aggregate structures, denominated by magnetic crosslinked enzyme aggregates (MCLEA). One of the advantages of such supports is the possibility of using magnetic separation for enzyme recovery, reducing costs and allowing reuse in continuous systems. Here, porcine pancreatic lipase (PPL) was immobilized onto functionalized magnetite support (Fe3O4-APTS) with a protein binding efficiency of 78.84%. Physical and chemical properties of the nanoparticles and immobilized lipase were characterized by X-ray diffraction (XDR), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, vibrating sample magnetometer measurements (VSM), and 57Fe Mössbauer spectroscopy. The immobilized lipase additionally exhibited improved stability across wide pH and temperature ranges compared with free lipase. The immobilized derivate also attained good reusability, maintaining 61.37% of its initial activity after 6 reaction cycles. Through magnetic behavior and also because of its surface modification to crosslinking the enzyme, the MCLEA produced in this work has enhanced the biocatalytic activities of PPL.

Characterization of Magnetic and Mineralogical Properties of Slag Particles from WEEE Processing

Magnetic separation has wide-ranging applications in both mineral processing and recycling industries. Nevertheless, its conventional utilization often overlooks the interplay between mineral and particle characteristics and their impact on operational conditions, ultimately influencing the efficacy of the separation process. This work describes a methodology able to achieve the comprehensive characterization and classification of Waste Electrical and Electronic Equipment (WEEE) slag. The primary objective is to establish a meaningful connection between the distinct properties of slag phases and their influence on the separation process. Our methodology consists of several stages. Firstly, the WEEE slag is sieved into distinct size classes, followed by classification into magnetic susceptibility classes by using the Frantz Isodynamic separator. To quantify the magnetic susceptibility of each class, we used a magnetic susceptibility balance, and to identify paramagnetic and ferromagnetic fractions and phases within these magnetic susceptibility classes, we conducted vibrating-sample magnetometer measurements. Finally, to establish a meaningful link between the magnetic characterization, mineralogical, and particle-level details, Mineral Liberation Analysis was conducted for each magnetic susceptibility class. This in-depth analysis, encompassing both particle properties and magnetic susceptibility classes, provides a better understanding of the separation behavior of different phases and can help to enrich phases with a specific range of magnetic susceptibility values. This knowledge advances progress towards the development of predictive separation models that are capable of bridging the gap between theoretical understanding and practical application in the field of magnetic separation.

Effect of Synthesizing Process on the Formation of Fe3O4 Magnetic Nanoparticles

In this work, the effect of synthesizing process on the morphology, structure, and magnetic properties of Fe3O4 magnetic nanoparticles have been studied by performing X-ray diffraction, scanning electronic microscopy, and vibrating sample magnetometer measurements. Fe3O4 nanoparticles were synthesized by hydrothermal and solvothermal methods. X-ray diffraction analysis revealed that both samples have cubic crystal phase. However, Fe2O3 impurity peaks were observed in the sample synthesized by hydrothermal method. The crystallite sizes of samples synthesized by hydrothermal and solvothermal methods were approximately 38 and 24 nm, respectively. The scanning electron microscope images show that spherical porous and cubic shape Fe3O4 nanoparticles were obtained by solvothermal and hydrothermal method, respectively. The average particle sizes of Fe3O4 samples synthesized by hydrothermal and solvothermal methods were determined as 220 and 450 nm, respectively. Both samples behave a soft ferromagnetic characteristic having almost zero coercive field. The magnetic saturation values of Fe3O4 nanoparticles synthesized by hydrothermal and solvothermal methods were determined as 28.78 and 77.31 emu/g, respectively. As a result of the characterizations, porous Fe3O4 nanoparticles synthesized by solvothermal method show better crystal structure, morphological and magnetic properties than Fe3O4 nanoparticles synthesized by hydrothermal method.

Preparation of Fe3O4@pectin nanocomposite hydrogel with high heating efficiency for hyperthermia applications

In this paper, magnetic nanoparticles (Fe3O4) were prepared by the co-precipitation method. The synthesized magnetic nanoparticles were added to the biocompatible polymer, pectin, for synthesizing Fe3O4@pectin (F@P) nanocomposite hydrogels. The structural, morphological, and magnetic characterizations were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and vibrating sample magnetometer (VSM) techniques. The XRD pattern confirmed the existence of the cubic phase of Fe3O4 nanoparticles. The FTIR spectra revealed the incorporation of pectin on the surface of Fe3O4 nanoparticles. The VSM measurement shows the proper magnetization curve of F@P nanocomposites, and good saturation magnetization value (∼33 emu/g). The results of hyperthermia temperature reveal an excellent heating efficiency of F@P nanocomposite hydrogel. The heating efficiency was quantified by a specific absorption rate (SAR) value and was obtained as 214 W/g for F@P nanocomposite hydrogels. This good hyperthermia result with biocompatible polymer (pectin) and hydrogel structure can be used for developing cancer treatment studies.

Photoelectrochemical, optical and magnetic properties of magnetite nanoparticles

AbstractMagnetite magnetic nanoparticles are prepared using olive leaf extract as a green reducing and stabilizing agents. After reaction the product is heated up to get rid of the organic compounds and get pure magnetite nanoparticles. Differential scanning calorimetry is used to study the phase transformation as a function of heating temperature. Scanning electron microscope and high resolution transmission electron microscope show spherical and crystallized nanoparticles with a size of 5 nm. X‐ray diffraction and Raman and x‐ray photoelectron spectroscopy indicate the formation of Magnetite phase with high cristallinity and purity. The synthesized Magnetite nanoparticles are semiconductors with gap energy around 2 eV. Observed by transmission electron microscope graphite rods with stacked carbon disks are decorated with the prepared nanoparticles and show enhanced photocurrent. The vibrating sample magnetometer measurements indicate that the prepared Magnetite nanoparticles have superparamagnetic behavior. These results are very promising for clinical and water splitting applications.

Soft Magnetic Properties and Electromagnetic Shielding Performance of Fe40Ni40B20 Microfibers

AbstractFe40Ni40B20 metallic glass is a key material among the many amorphous systems investigated thus far, owing to its high strength and appealing soft magnetic properties that make it suitable for use as transformer cores. In this study, Fe40Ni40B20 microfibers are fabricated down to 5 µm diameter. Three different melt–spinning wheel velocities: ≈51 m s−1, ≈59 m s−1, and ≈63 m s−1 (MG1, MG2, MG3) are used. Their fully amorphous structure is confirmed using X–ray diffraction, and differential scanning calorimetry (DSC) traces reveal a larger relaxation profile for the higher–quenched microfiber. Vibrating sample magnetometer measurements showed a higher saturation magnetization of 136 emug−1 for annealed metallic glass microfibers with a wheel velocity of 59.66 ms−1. Cylindrical magnetic field shields are obtained by aligning and wrapping the fibers around a cast. The observed anisotropic static field shielding behavior is in accordance with the microfibers' anisotropic nature. Composite samples are also produced by embedding the microfibers in an epoxy matrix to investigate their electromagnetic properties at GHz frequencies. Inclusion of the microfibers increase the composite's attenuation constant by 20 to 25 times, making it an ideal candidate for applications in the communications frequency range.

Synthesis, Structural and Magnetic Characterization of Superparamagnetic Ni0.3Zn0.7Cr2−xFexO4 Oxides Obtained by Sol-Gel Method

The sol-gel process was used to produce ferrite Ni0.3Zn0.7Cr2−xFexO4 compounds with x = 0, 0.4, and 1.6, which were then subsequently calcined at several temperatures up to 1448 K for 48 h in an air atmosphere. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and 57Fe Mössbauer spectrometry were used to examine the structure and magnetic characteristics of the produced nanoparticles. A single-phase pure Ni0.3Zn0.7Cr2−xFexO4 nanoparticle had formed. The cubic Fd3¯m spinel structure contained indexes for all diffraction peaks. The crystallite size is a perfect fit for a value of 165 ± 8 nm. Based on the Rietveld analysis and the VSM measurements, the low magnetization Ms of Ni0.3Zn0.7Cr2−xFexO4 samples was explained by the absence of ferromagnetic Ni2+ ions and the occupancy of Zn2+ ions with no magnetic moments in all tetrahedral locations. Moreover, because of the weak interactions between Fe3+ ions in the octahedral locations, the magnetization of the current nanocrystals is low or nonexistent. According to Mössbauer analyses, the complicated hyperfine structures are consistent with a number of different chemical atomic neighbors, such as Ni2+, Zn2+, Cr3+, and Fe3+ species that have various magnetic moments. A Fe-rich neighbor is known to have the highest values of the hyperfine field at Fe sites, while Ni- and Cr-rich neighbors are responsible for the intermediate values and Zn-rich neighbors are responsible for the quadrupolar component.

Synthesis of nanocrystalline nickel-iron alloys-A novel chemical reduction method

Ultra fine magnetic particles of NixFe100-x alloys were synthesized by a novel chemical reduction of the precursor salts by an alkali earth metal (Al) in an aqueous medium. In this method we successfully prepared alloy nanocrystalline powders without any bimetallic phases. The alloys were formed with Fe at% in two distinct bands 18–30 and 60–90 irrespective of the concentration ratios of Ni and Fe sources. The NixFe100-x alloy composition showed a transformation from fcc to bcc structure .The Ni rich alloys namely NixFe100-x (x = 90 to75) which correspond to 18–30 band Fe at%.composition were formed in fcc (or simple cubic) phase, whereas the Fe rich alloys (x = 80) which correspond to 66–90 band Fe at%.composition were formed in bcc phase. The observed grain sizes for Ni rich (i.e., 18–30 Fe at.%) alloys lie in the range of 6–9 nm whereas for the Fe rich alloys grains are in the 20–27 nm range. Magnetization measurements shows that all the alloys exhibit ferromagnetic behaviour and the saturation magnetization values increase linearly with iron content. Vibrating sample magnetometer measurements shows that all samples exhibit ferromagnetic behaviour with increasing saturation magnetization as a function of iron content. SEM studies shows that the particles were found be large and agglomerated.

Analysis on the cation distribution of Mg x Ni1−x Fe2O4 (x = 0, 0.25, 0.5, 0.75, 1) using Mössbauer spectroscopy and magnetic measurement

Mg x Ni1−x Fe2O4 (x = 0, 0.25, 0.5, 0.75, 1) spinel ferrite material was analyzed to determine its magnetic properties and structure. X-ray diffraction (XRD), Mössbauer spectroscopy, and vibrating sample magnetometer (VSM) characterization were performed on the samples prepared using the sol–gel method. The results from XRD confirmed the existence of the single-phase cubic spinel structures , as well as the evolution of the crystalline size (D), the lattice parameter (a) and cell volume in compounds. The Mössbauer spectra showed the distribution of cations and changes in the magnetic properties of the sample. VSM measurement revealed that the samples were room-temperature ferromagnetic. Moreover, the saturation magnetization (M s) of the samples changed with the Mg2+ ion content x, and a maximum occured at x = 0.5. Doping with Mg2+ ions increased the transfer of Ni2+ ions to tetrahedral sites, thus increasing the magnetic moment difference between tetrahedral (A) and octahedral (B) sites. Specifically, doping NiFe2O4 with Mg2+ ions can enhance its magnetic properties and enhance its saturation magnetization.

Effects of Chromium(III) Ion Doping on Structural, Optical, and Magnetic Properties of Nickel–Cobalt Ferrite Nanoparticle

Chromium(III)-doped nickel–ferrite nanoparticles, with the general formula Ni0.5Co0.5CrxFe2−xO4 (x = 0.0, 0.10, and 0.20), were prepared by the sol–gel method. The prepared samples were sintered at 700°C for 5 hr. The XRD result showed that the prepared samples are in single-phase partially inverse cubic spinel ferrite structures with space group Fd3m. From the XRD characterization, the average crystallite size for all samples decreased from 39.54 to 30.42 nm and the lattice parameters are found to be 0.8324, 0.8320, and 0.8314 nm for x = 0.0, 0.10, and 0.20, respectively. The energy dispersive X-ray (EDX) spectroscopy analysis confirmed the presence of all ions as per the stoichiometric ratios. The vibrating sample magnetometer measurements revealed that the saturation magnetization (Ms), remnant magnetization (Mr), and coercive fields are found to be decreased with increasing concentration of Cr3+ ions. The UV–vis spectroscopy analysis showed that the energy bandgap (Eg) increased with increasing the concentration of Cr3+ ion from 1.61 to 1.96 eV. The Fourier transform infrared spectra show the two main absorption bands at 407–424 cm−1 and 547–588 cm−1 corresponding to stretching vibrations of metal–oxygen in the octahedral and tetrahedral sites, respectively.

Magnetic characterization of La3+ and Li1+ co-substituted M-type strontium hexaferrite

Effects of stoichiometric La3+–Li1+ co-substitution on magnetic properties of M-type strontium hexaferrites Sr1-xLaxFe12-x/2Lix/2O19 (x = 0, 0.25, 0.4, 0.5, 0.6) have been studied by using crystallographic and magnetic measurements. Samples were prepared thru conventional ceramic technique and their powder X-ray diffraction profiles were checked by the Rietveld method using GSAS package. Field emission scanning electron microscopy images show that lithium addition derives the enhanced degree of grain separation, which significantly affects the coercivity and anisotropy constant as examined by vibrating sample magnetometer measurement. 57Fe Mössbauer spectra of the samples show that Li1+ ions preferentially occupy the 2a sites, which causes the decrease of MS with lithium addition.

Structural and magnetic analysis of Cd-Zn spinel ferrite nanoparticles

Sol-gel auto-combustion synthesis technique was employed to synthesize Cd-Zn ferrite nanoparticles with composition Zn1-xCdxFe2O4, where 0.0 ≤ x ≤ 1.0. The physical properties of prepared samples were inspected by using x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and vibration sample magnetometer (VSM) techniques. XRD analysis confirmed the formation of Cd-Zn spinel nanoferrites with an increase in experimental lattice constant from 8.37 Å to 8.74 Å for zinc and cadmium ferrite samples, respectively. Variation of tetrahedral and octahedral hopping lengths, crystallite size, microstrain and dislocation density with Cd-content has been investigated and elucidated. SEM micrographs showed agglomeration of nearly-spherical grains that increased in size with Cd-content increase. FTIR analysis confirmed the existence of the characteristic tetrahedral and octahedral stretching vibrations of metal ion and oxygen complex in the range 429–558 cm−1. VSM measurements revealed a tuning in coercivity to higher values and a decrease in saturation magnetization as Cd-content increased. The calculated cations distribution, bond lengths, bond angles and interionic distances between cations at tetrahedral and octahedral sites attribute the observed decrease in saturation magnetization to weak interaction between cations in the two sites.

A study of structural, electrical and magnetic properties of zinc substituted magnesium ferrite

Zinc substituted magnesium ferrite with the compositional formula Mg1-xZnxFe2O4 (where x = 0.05, 0.10, 0.15, 0.20, 0.25) was synthesized using auto-combustion method. The ash obtained was calcined in microwave furnace at 550 °C for 30 min. The calcined powder was further annealed at 600 °C in the furnace. The structural, dielectric and magnetic properties were studied using XRD, LCR meter and vibrating sample magnetometer (VSM) for all the samples. XRD pattern confirmed the formation of the spinel cubic phase of magnesium ferrite. Lattice constants and density were determined from the Rietveld analysis of the XRD pattern. The crystallite size of all the samples was calculated. Presence of Fe-O bond in all the samples was confirmed by FTIR spectra. Dielectric properties such as dielectric constant and dielectric loss of all the samples were studied as a function of frequency. Both the quantities show dispersion with frequency. Dielectric constant and ac conductivity were found to be minimum when the concentration of Zn2+ is x = 0.15 while dielectric loss is maximum at this concentration. The VSM measurement showed that the saturation magnetization increased with the Zn2+ concentration up to x = 0.20. Electric polarizations of the samples were studied using P-E hysteresis loop. It was found that electric polarization decreased with the increasing concentration of Zn2+ up to x = 0.20.

Magnetic Properties Analysis of Synthesis of Poly-(Vinyl Alcohol) / Clay / Nanomagnetite Composites: Application for Wastewater Filter

The composites of poly–(vinyl alcohol) (PVA)/clay/Fe3O4 (magnetite) were synthesized with Fe(II) in-situ via hydrolysis method. The films were obtained as films by employing natural clay containing montmorrilonite (aluminosilicate) using casting technique. The weight variations of each component were also investigated. The resulting films were characterized with fourier transform infrared (FT-IR) to analyze their functional groups, and then X-ray diffractometer (XRD) was used to check the formation of magnetite and it was combined with Deybe-Scherrer equation to determine the theoretical size of magnetite. Along with that, vibrating sample magnetometer (VSM) analysis was carried out in order to measure the magnetic saturation brought by the magnetite inside composite system. FT-IR spectra showed peak around 610 cm-1and XRD diffracttogram pattern showed four characteristic peaks indicating (200); (311); and (511). Both results confirmed the formation of magnetite inside composite system. The result of VSM measurement showed that increasing PVA weight would lead into the decrease of the magnetic saturation of magnetite-contained composites due to hydroxyl group from PVA control its crystalline. Conversely, the reverse plot would be acquired if the precursor Fe(II)weight was augmented in the composite system due to another iron oxide species i.e.: goethite was predicted to form as the intermediate of magnetite. On the other hand, the amount variation of the aluminosilicate material was resulting no coherent plot through magnetic saturation value.

Novel biocompatible nanomaterial for biomedical application: Structural, morphological, magnetic, and in vivo toxicity investigations

Assessing the biocompatibility of magnetic nanoparticles for biomedical applications is highly demanded and attracted an increasing interest in the last years. We, herein report the synthesis, physical characterization, and biocompatibility of CoFe(2-x-y-z)GdxSmyHozO4 (x = y = z = 0, 0.01) nanoparticles (NPs) synthesized by the auto-combustion method for the first time. The physicochemical and magnetic properties of the synthesized nanoparticles were fully characterized using various techniques including X-ray diffraction (XRD), Fourier transforms infrared spectra (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). A single-phase with a space group Fd-3m and mixed spinel structure were confirmed by XRD, Rietveld analysis, and the cation distribution study. FTIR confirms the formation of the crystallographic sites of the spinel structure, namely the octahedral site and the tetrahedral site. The nanoparticles exhibited a quasi-spherical shape with size distribution (24–51 nm). VSM measurements reveal that magnetic properties can be tuned by doping for biomedical applications. To evaluate the safety of our nanoparticle sub-chronic toxicity was highlighted in Wistar rats by oral administration at doses of 500, 250,125, and 50 mg/kg and by intraperitoneal injection at doses of 40,20,10, and 5 mg/kg. Results showed no significant changes in the hematological parameters, serum biochemical system, organ weight, and histopathological examination (p > 0,05) for doses below 250 mg/kg and 40 mg/kg administered orally or by intraperitoneal injection respectively. The results of the current study suggesting that treatment with the nanoparticle for 28 days does not produce any significant toxicity in the male and female rats for the either using voices (oral, intraperitoneal) except at high doses. These findings reported here strongly suggest that the as-prepared nanoparticles can be used in several biomedical applications, including separation and purification, drug delivery, imaging (MRI contrast), and therapy (hyperthermia).

Synthesis, characterization, and investigation of electrochemical hydrogen storage capacity in barium hexaferrite nanocomposite

Hydrogen is considered as one of the most renewable and also efficient fuels. When hydrogen is burned, its only product is water. But the most important issue in the use of hydrogen is its storage. Hydrogen must be stored reversibly in a way that is completely safe and has high storage efficiency. Due to obtaining high-efficiency hydrogen storage, new nanostructures based on barium hexaferrite nanostructures (BaFe12O19) and functionalized multi-walled carbon nanotubes BaFe12O19 nanocomposite (BaFe12O19/MWCNTs) are synthesized via sol-gel combustion method. The nanocomposites are confirmed through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM) techniques. Further, the hydrogen storage capacity of BaFe12O19/MWCNTs nanocomposite is assessed by chronopotentiometry analysis (CHP). The XRD studies demonstrates that the average crystallite sizes of the BaFe12O19 and nanocomposite are estimated to be about 16.3 and 7.6 nm, respectively. Also, the VSM measurement shows a saturation magnetization values (Ms) of 20.1 and 1.3 emu/g for BaFe12O19 and BaFe12O19/MWCNTs nanocomposite, respectively. The electrochemical consequences indicate that the BaFe12O19/MWCNTs nanocomposite has a high capacity for hydrogen storage and discharge rate. The maximum discharge capacity of BaFe12O19/MWCNTs nanocomposite reaches about 360 mAh/g in the first cycle to approximately 3600 mAh/g after 20 cycles under an optimal current of 2 mA. As a result, the BaFe12O19/MWCNTs nanocomposite showed a good capacity as a promising active ingredient for hydrogen storage devices.

Cytotoxic effect of functionalized superparamagnetic samarium doped iron oxide nanoparticles for hyperthermia application

Magnetic Fluid Hyperthermia (MFH) is an emerging and safe technique for cancer treatment. Radiotherapy and Chemotherapy are widely adopted techniques for treating cancer but cause damage to the nearby healthy tissue. This paves the way for hyperthermia treatment for cancer. Since healthy cells are more heat-tolerant than malignant cells, magnetic nanoparticles with superparamagnetic properties were used in hyperthermia treatment. Surface modified magnetite (Fe3O4) iron oxide nanoparticles with enhanced stability, solubility, bio-compatibility and magnetic property were employed in hyperthermia treatment. In the present study, Superparamagnetic Samarium doped magnetite (Fe3O4:Sm) nanoparticles were functionalized with Oleylamine (OAm) and polyvinyl alcohol (PVA) by the sol-gel process. The obtained nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and UV–Visible diffuse reflectance spectroscopy (UV-DRS), Thermogravimetric analysis (TGA) and Vibrating Sample Magnetometer (VSM). From XRD data, the crystallite size of oleylamine coated samarium doped magnetite (OAm–Fe3O4:Sm) and PVA-coated samarium doped Fe3O4 (PVA- Fe3O4:Sm) were found to be 9.5 nm and 10.9 nm, respectively. TEM images of the functionalized nanoparticles were visualized as a spherical structure with reduced agglomeration. UV-DRS gives the bandgap value of OAm–Fe3O4:Sm and PVA- Fe3O4:Sm coated samarium doped magnetite to be 2.3 eV and 2 eV respectively. VSM measurement of OAm-Fe3O4:Sm and PVA- Fe3O4:Sm coated, showed superparamagnetic behaviour. The cytotoxicity study on the L929 cell line shows that both oleylamine and PVA-coated samarium doped magnetite were less toxic and biocompatible compared to the uncoated Fe3O4:Sm. The hyperthermia study reveals a rise in temperature within a few seconds with a high Specific Absorption Rate (SAR) value, confirming that the functionalized Samarium doped Fe3O4 was an effective nanomaterial for hyperthermia application.

Designed Synthesis of Fe x Co100−x Alloy Nanoparticles by Polyol Reduction: An Evolution of Structural, Morphological and Magnetic Properties

Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">100−<i>x</i></sub> nanoparticles with different stoichiometry ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x = 0$ </tex-math></inline-formula> –100) have been prepared by a facile synthesis process and compositions confirmed using X-ray fluorescence spectroscopy. X-ray diffraction measurements suggest alloy formation in the body-centered cubic (BCC) phase, with a progressive shift of peak positions to account for the stoichiometric changes. The evolution of nanoparticle morphology is from cubic for iron to hexagonal for cobalt, and the entire composition range has been examined. Magnetic behavior has been accessed by Mössbauer spectroscopy and vibrating sample magnetometric measurements, which suggests an increase of magnetization values of iron upon alloying with cobalt. A detailed account of the synthesis scheme has been presented, to achieve uniform alloy nanoparticles in the pristine state with minimum aggregation and surface oxidation, by carefully adjusting the reaction timescales.

Effect of Nd3+ ions on structural, spectral, magnetic, and dielectric properties of Co–Zn soft ferrites synthesized via sol-gel technique

The substitution of Neodymium (Nd) in the cobalt - zinc (Co–Zn) ferrite was analyzed. The sol-gel technique was used to synthesize these ceramic samples. The crystalline structural, molecular characterizations, and magnetic properties were analyzed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) experiments, and vibrating sample magnetometer (VSM) respectively. XRD patterns revealed the single-phase cubic spinel structure of the samples. Lattice parameter varied from 8.41 to 8.38 Å with the inclusion of Nd concentration. The existence of two characteristic frequency bands in the range of 400–1400 cm−1 was confirmed by FTIR spectra. VSM measurements showed the magnetic behaviour at room temperature. The saturation magnetization was noted to decrease from 81 to 66 emu/g with increasing the Nd concentration. The sample having step size x = 0.025 revealed the highest coercivity and retentivity. Dielectric properties were studied and showed variation in dielectric constant, dielectric loss, ac conductivity, and energy dissipation (tangent loss) in the prepared materials.

Synthesis of Cobalt Ferrite Nanoparticles Using Microemulsion Method: Structure, Morphology, and Magnetic Properties

Cobalt ferrite nanoparticles were prepared by the microemulsion method. Different values of pH of the microemulsion were maintained to find out the optimum pH to prepare cobalt ferrite nanoparticles. Prepared nanoparticles were characterized using X-ray Powder Diffraction (XRD), Vibrating Sample Magnetometer (VSM), and Scanning Electron Microscope (SEM). Rietveld refinement was used to analyze the crystal structure of the prepared cobalt ferrite nanoparticles. The crystallite size of prepared nanoparticles has been found from XRD in the range of 13.79 nm to 30.40 nm. The saturation magnetization, remanent magnetization, and coercivity have been found to be 12.05 emu/g, 0.77 emu/g, and 118.912 Oe respectively from VSM measurements. Journal of Engineering Science 13(1), 2022, 81-87