Magnetic Hysteresis Curves Research Articles

Multifunctional hybrid films made from CoT3OTx4 and CoFeT2OT4 nanoparticles inside a poly 3-hydroxybutyrate matrix and study of their impact in methyl orange photodegradation.

This work aims to produce hybrid materials with potential applications in dye photodegradation. Therefore, hybrid films were obtained by incorporating cobalt (II, III) oxide (Co3O4) or cobalt ferrite (CoFe2O4) nanoparticles (NPs) with 18 ± 1.6 nm and 26 ± 1.3 nm, respectively, into a poly 3-hydroxybutyrate (P3HB) polymeric matrix. The Co3O4@P3HB and CoFe2O4@P3HB hybrid films were fabricated by solvent casting in a ratio of 85 mg to 15 mg (P3HB-NPs). Different spectroscopic and microscopy techniques characterized the Co3O4 and CoFe2O4 NPs and the P3HB, Co3O4@P3HB and CoFe2O4@P3HB films. The optical band gap for Co3O4 and CoFe2O4 NPs was estimated from their diffuse reflectance spectra (DRS) around 2.5 eV. X-ray diffraction (XRD) of the hybrid films revealed that the nanometric sizes of the Co3O4 and CoFe2O4 nanoparticles incorporated into the P3HB are preserved. The magnetic hysteresis curve of CoFe2O4 nanoparticles and CoFe2O4@P3HB film showed a ferromagnetic behaviour at 300 K. Transmission electron microscopy (TEM) confirmed the formation of nanocrystals, and scanning electron microscopy (SEM) provided evidence for the successful incorporation of the NPs into the P3HB matrix. The surface roughness and hydrophilicity of the hybrid films are increased compared to the P3HB film. The impact of the nanoparticles and the hybrid films on the photodegradation of methyl orange (MO) in its acidic form was studied. The photodegradation tests were carried out by direct sunlight exposure. The CoFe2O4@P3HB hybrid film achieved 85% photodegradation efficiency of a methyl orange solution of 20 ppm after 15 minutes of exposure to sunlight. After 30 minutes of exposure to sunlight, the nanoparticles and the hybrid films reached about 90% of the MO degradation. The results suggest that combining nanoparticles with the polymer significantly enhances photodegradation compared to isolated nanoparticles.

Exploring the Multifunctional Properties of (Sr, Ni)‐Co‐Doped BaTiO3: Structural Characterization and Electromagnetic Characteristics

The structural and electromagnetic properties of various Ba1−x(Sr0.5Ni0.5)xTiO3 are extensively investigated. X‐ray diffraction and Rietveld refinement are used to perform a structural study. With doping substances, bulk and theoretical densities decrease. The crystallite size is calculated using Scherrer and Williamson–Hall method. The microstructural properties are examined using images from field‐emission scanning electron microscope. The observed values of dielectric constants are found to agree with the porosity‐corrected dielectric constants. The nonlinear modified Debye equation (NLMDE) displays a reasonable goodness of fit value for the first five samples. A small polaron hopping mechanism may be responsible for the frequency‐dependent AC conductivity observed in all samples confirming the Jonscher power law. It is discovered that permeability initially increases and then decreases with doping substances. Initial permeability, experimental data from the magnetic hysteresis (M–H) curve, and law‐of‐approach‐to‐saturation techniques show that Ba0.85(Sr0.5Ni0.5)0.15TiO3 and Ba0.75(Sr0.5Ni0.5)0.25TiO3 ceramics have enhanced electromagnetic properties. These ceramics are useful for fabricating electromagnetic sensors.

Simple extraction method of magnetic hysteresis curve from measurement data

Simple extraction method of magnetic hysteresis curve from measurement data

Investigation of annealing temperature effect on structural, morphological, optical, magnetic, and dielectric properties of cobalt-doped manganese ferrites

Spinel ferrite Mn0.95Co0.05Fe2O4 was prepared via chemical co-precipitation routes and annealed at four distinct temperatures of 600 °C, 650 °C, 700 °C, and 750 °C. The XRD peak confirmed a single-phase cubic spinel structure, with an increasing crystallite size of 21.64–23.98 nm by the annealing effect. The TEM images show an increase in particle size with rising annealing temperature and indicate well-defined nanocrystalline Mn-Co ferrite. FT-IR spectra detected two vibrational modes at interstitial sub-lattice sites, identifying Co-O, Mn-O, and Fe-O bonds with the spinel structure of Mn-Co ferrite. UV–vis–NIR reflectance revealed an optimal direct band gap of 3.76–4.70 eV, indicating a scope of semiconducting behaviors in the nanocatalysts. In the magnetic hysteresis curve, saturation magnetization decreased while coercivity increased with rising annealing and crystallite size. The M-T loop reveals the Curie temperature of Mn-Co ferrite decreases from 533.84 °C to 382.74 °C. Frequency-dependent complex permeability at different annealing temperatures shows stable initial permeability over a wide frequency range (1 kHz to 100 MHz) and a quality factor several times higher due to reduced magnetic tangent loss. The real dielectric constant and losses decline in rising alternating fields (100 Hz to 1 MHz) and stabilize at higher frequencies following Maxwell-Wagner-type polarization. Eventually, structural, morphological, and magnetic properties are performed relatively well at higher annealing temperatures, and optical and dielectric properties are performed at lower annealing temperatures.

The impact of cobalt oxide additions and heat treatment on wollastonite for magnetic applications

Magnetic nanocomposite was prepared using the wet chemical precipitation approach with varying amounts of cobaltous oxide (CoO). The concentrations of CoO were 0.5, 3.5, 6.5, and 9.5 g per 100 % wollastonite composition. Samples were sintered separately at 1000 and 1200 °C. X-ray diffraction analysis (XRD) of the sintered parent sample revealed the formation of wollastonite CaSiO3 and larnite Ca2SiO4, as well as a minor silicon oxide SiO2 phase. In CoO-doped samples, Co-åkermanite Ca2CoSi2O7 and other phases were formed. The XRD and scanning electron microscope SEM confirm the samples' submicron and nanocrystalline microstructure. The Fourier transform infrared spectroscopy (FTIR) and Raman spectra (RS) of investigated samples sintered at 1000 and 1200 °C revealed their bond structure. Both analyses confirmed that incorporating CoO into CaSiO3 significantly improved its vibrational modes, reflecting structural modifications. By increasing the cobalt oxide content from 3.5 to 9.5 wt%, the samples attain the ideal paramagnetic state, as demonstrated by the magnetic hysteresis (M − H) curve, which is linearly reversible. Formation of the Ca2CoSi2O7 significantly alters the magnetic characteristics of the samples, whether through increasing the cobalt oxide concentration up to 9.5 wt% or modifying the sintering temperature. This enables the prepared nonocomposites to be suitable for novel magnetic applications.

Formation of magnetite within the droplet phase of immiscible glass

An immiscible glass system consisting of a continuous silica-rich phase and a discontinuous droplet phase enriched in phosphorus form the glassy framework for a novel magnetite glass-ceramic. Upon cooling from the molten state, the material phase separates into the droplet-in-matrix structure and magnetite precipitates spontaneously within the phosphorus-enriched droplet phase. Magnetic hysteresis curves of an exemplary magnetite glass-ceramic show a saturation magnetization of ∼20 emu/g and magnetic remanence of 2.6 emu/g for a maximum externally applied field of 30 kOe. This novel material space provides a simple and economical means to produce magnetite glass-ceramics with potential suitability for a variety of biomedical applications.

Small polaron hopping and tunneling mechanisms in Ba0.9La0.1Fe12O19 hexaferrite ceramic at low temperatures

The correlation between dielectric relaxation and conduction mechanisms in the Ba0.9La0.1Fe12O19 ceramic hexaferrite, at temperatures below 100 K was investigated. The sample was prepared using the conventional solid-state reaction method. X-ray diffraction analysis indicated that the sample is composed of a hexagonal BaFe12O19 phase (lattice parameters a = 5.8778(6) Å and c = 23.170(3) Å) and a small proportion of hematite (α-Fe2O3). The average grain size is 1.48 ± 0.4 μm, with irregular hexagonal and agglomerated grains. The magnetic hysteresis curve shows characteristics typical of ferro and ferrimagnetic materials, with an effective magnetic anisotropy coefficient of 0.960×106 emu/cm3 and an anisotropy field of 1.587×104 Oe. A dielectric relaxation process is observed between 50 and 100 K, with an activation energy of 60.4 ± 0.4 meV and a characteristic relaxation time of 2.09 ×10−10 s, mainly attributed to the electrical behavior of the grains. Two conduction mechanisms were identified: small polaron tunneling (high temperatures and low frequencies) and correlated barrier hopping of electrons (low temperatures and high frequencies). The activation energy for free polaron formation, according to the Komine-Iguchi hopping polarization model, was 7.12 ± 0.02 meV. In the dielectric modulus relaxation process between 30 and 54 K, the activation energy was 40.8 ± 0.9 meV, with a characteristic relaxation time of 2.41×10−10 s. The small polaron conductivity in the grain region was 67.52 meV and 54.0 meV in the grain boundary region. The results highlight that the polarization and conduction mechanisms in this ceramic at low temperatures are dominated by small polaron hopping and tunneling, and emphasize the influence of La3+ doping on the structural, magnetic, and electrical properties of barium hexaferrite.

High Temperature and FORC Investigations of Semiconducting/Ferromagnetic Nanocomposites

In the frame of this work the temperature-dependency of the magnetization of various composite systems consisting of porous silicon (PSi) and silicon nanotubes (SiNTs) with embedded Ni, Co, NiCo, FePt, and Fe3O4 structures is discussed. The temperature is varied between 80 and 1273 K which allows to determine the Curie Temperature of the composites which is higher than for the corresponding bulk materials. High temperatures result in an alteration of the chemical sample-composition. Depending on the temperature specific metal-silicide formation occurs usually beginning around 600 K. This leads to modified magnetic behavior of the composites which can be observed by repeated measurements. Magnetic cross-talk between metal deposits can be controlled by the morphology of the porous silicon (distance between the pores) or silicon nanotubes (wall thickness) and also by the distribution and size of the deposits within the pores. To get a clear knowledge about the magnetic interactions single hysteresis curves are not sufficient and thus first order reversal curves (FORC) are performed.The employed PSi is produced by anodization of a highly n-doped silicon wafer. The structures offer an average pore-diameter of 50 nm and a mean distance between the pores of 50 nm which ensures a clear separation of the pores, a crucial point to achieve the appropriate magnetic properties. The SiNTs are produced by ZnO seed deposition on a silicon wafer, growing of the ZnO nanowire arrays (NWA), followed by Si deposition and finally etching off the ZnO. Ni and Co are deposited electrochemically in using for Ni formation a Watts electrolyte, consisting of NiCl2, NiSO4 and H3BO3 and for Co deposition a CoSO4 solution is utilized. A further approach is to grow Co particles inside the pores/tubes in using a CoCl2 6H2O and NaBH4 solution. Fe3O4 are synthesized by high temperature decomposition in the presence of an organic precursor (1). The synthesized particles are infiltrated into the pores/tubes with the help of a magnet beneath the samples. FePt nanocrystals are formed within the SiNTs and PSi by a multistep process, using a solution containing Citric acid, H2PtCl6 6H2O, and Fe(NO3)3 9H2O.Considering Ni loaded porous silicon samples, the magnetic response is recorded in dependence on the temperature to figure out the Curie temperature (TC) of the composite system which is determined from hysteresis curves measured at various temperatures between 80 and 950 K in field steps of 50 K. TC is determined at 700 K, which is about 70 K higher than for bulk Ni. Co loaded porous silicon has been measured up to 1200 K which was still too low to determine TC. TC of bulk magnetite is at 858 K. The investigated porous silicon sample with 8 nm Fe3O4 NPs infiltrated into the pores shows TC around 900 K, 42 K higher than for the bulk material. In the case of FePt loading, the system with PSi as template shows a lower TC compared to SiNTs. The investigations show that the TC of the investigated nanostructured composite systems is always higher than for the according bulk materials. FORC diagrams are used to detremine magnetostatic interactions between the metal deposits. Magnetic coupling is present for Ni, Co and NiCo deposits, wheras in the case of FePt NP loading no magnetic cross-talk between the particles is observed.(1) L. Gutierrez, R. Costo, C. Grüttner, F. Westphal, N. Gehrke, D. Heinke, A. Fornata, Q.A. Pankhurst, C, Johansson, S. Veintemillas-Verdaguer, M.P. Morales,Dalton Transactions, 44, 2943, (2015).

Low temperature garnet phase formation in Mn-substituted Y3Fe5-xMnxO12 nanoparticles via citrate combustion synthesis

In this article, we report on the formation of a low-temperature garnet phase in Mn-substituted Y3Fe5-xMnxO12 (x = 0, 0.05, 0.15, and 0.25) nanopowders. We studied the structural, microstructural, static, and dynamic magnetic properties of Mn-substituted Y3Fe5-xMnxO12 (YIG) nanopowders calcined at two different temperatures. The Mn-substituted garnet powders were synthesized using the citrate combustion method followed by calcination at 800 and 1200 °C for 3 h. An increase in Mn substitution (x = 0.15, 0.25) favored the growth of a single garnet phase at low temperatures, even at 800 °C. The lattice constant of these samples ranged from 12.3815 to 12.3679 Å. Microstructural and morphological studies revealed the growth of homogeneous and dense particles, with an average particle size in the range of ∼35–58 nm, close to the single-domain particle size in YIG. Microwave resonance spectra and magnetic hysteresis curves revealed the formation of a ferromagnetic phase in undoped and Mn-doped garnet ferrites at room temperature. The maximum saturation magnetization (26 emu/g) was observed for the sample with Mn content x = 0.05 at 1200 °C, while the largest coercivity (33 Oe) was found for the sample with Mn content x = 0.15 at 1200 °C, among all the samples. The increase in Mn content led to a decrease in peak-to-peak linewidth of FMR spectra from 698.8 to 569.4 G at 800 °C and from 916 to 614.7 G at 1200 °C. This study suggests that Mn substitution in YIG garnet improves structural properties and enhances magnetic anisotropy.

Antioxidant activity and cytotoxicity of greigite nanoparticles synthesized by hydrothermal technique.

The effects of 180, 210, and 230°C reaction temperatures on the structural and magnetic properties of synthesized iron sulfide nanoparticles were studied. The Rietveld refinement analysis result of the X-ray diffraction data indicated that greigite was the dominant phase in all samples. The sample was prepared at 210°C for 18h and had a greater wt% ratio of the greigite phase. The crystallite and particle sizes increased with increasing reaction temperatures. Scanning electron microscope images confirmed the presence of aggregation of synthesized rod-shaped nanoparticles. The magnetic hysteresis curves of all samples showed ferromagnetic behavior at room temperature. The magnetic saturation of three samples increases with increased reaction temperature, but the coercive force has the opposite behavior. Antioxidant activity and cytotoxicity of the sample synthesized at 210°C were investigated. This sample killed cancer cells at relatively moderate and high concentrations with high viability of normal cells, demonstrating the sample's suitability for use in killing cancer cells while avoiding normal cells.

High Temperature and FORC Investigations of Semiconducting/Ferromagnetic Nanocomposites

In the frame of this work the temperature-dependency of the magnetization of various composite systems consisting of porous silicon (PSi) and silicon nanotubes (SiNTs) with embedded Ni, NiCo, FePt, and Fe3O4 structures is discussed. The temperature is varied between 80 and 1273 K which allows to determine the Curie Temperature of the composites which is higher than for the corresponding bulk materials. Magnetic cross-talk between metal deposits can be controlled by the morphology of the porous silicon (pore diameter and distance between the pores) or silicon nanotubes (inner diameter and wall thickness) and also by the distribution and size of the deposits within the pores. To get a clear knowledge about the magnetic interactions single hysteresis curves are not sufficient and thus first order reversal curves (FORC) are performed. Magnetic coupling is present for Ni, Co and NiCo deposits, whereas in the case of Fe3O4 and FePt nanoparticle loading no magnetic cross-talk between the particles is observed.

Effect of annealing temperature on crystallographic texture, magnetic and microwave properties of barium ferrite thin films

Due to it has large saturation magnetization (Ms), high magnetocrystalline anisotropy field and high ferromagnetic resonance (FMR) frequency, barium ferrite (BaM) has attracted more and more attentions in the fields of magnetic recording media, permanent magnets and microwave devices. Here, BaM thin films were deposited on Pt/TiO2/SiO2/Si substrates, and the effect of annealing temperature on the microstructure, magnetic and microwave properties of barium ferrite thin films was investigated in detail. It is found that when the BaM thin film was annealed at 1035 °C, it has good properties. The XRD data provide clear evidence that the BaM thin films have high c-axis orientation, and the Lotgering factor is as high as 0.96. The AFM morphology show that BaM grains are out of the film plane, and they are hexagonal. The magnetic hysteresis curves indicated that both saturated magnetization (4πMs), remanence ratio and coercive (Hc) for out of plane increase with increasing Ta first, then decreased, and get the maximum value at 1035 °C. The ferromagnetic resonance (FMR) measurement show that the FMR linewidth is 143 Oe@50 GHz, it means that this this sample has low microwave loss in millimeter wave loss, and the FMR absorption can be tuned by applied magnetic field. These results make sure that this BaM thin film is possible use in millimeter wave devices such as filers, circulators and isolators.

Effect of rare earth (Sm3+) substitution in mixed Ni-Zn-Co ferrites: Structural, magnetic, and DC electrical resistivity studies

NiZnCo ferrite has good magnetic properties and is one of the core materials used in magnetic devices. The solid-state reaction approach is utilized to synthesize Ni0.4Zn0.35Co0.25Fe2-xSmxO4 (x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.1) ferrites for investigation of structural, morphological, functional, magnetic and electrical resistivity properties using various characterization techniques. The techniques used for characterization were XRD, SEM, FTIR, VSM, and DC electrical resistivity. XRD spectra were used to determine phase confirmation, cubic crystallite size, andtheir variation with dopant content. No additional phase or impurity was found. The SEM pictures revealed ahomogeneous spherical particle formation with minimal porosity. With absorption bands under 1000 cm−1, FTIR spectra indicate the formation of a spinel structure. Tetrahedral (580 to 599 cm−1) and octahedral (388 to 399 cm−1) bond changes can be seen in infrared spectra. The magnetic hysteresis curves revealed soft ferromagnetic behavior, with coercivity (Oe) (532.13 to 312.10Oe) rising and saturation magnetization (Ms) (83.51 to 60.75 emu/g) falling as doping concentration increased. The DC electrical resistivity of synthesized nanoparticles with various compositions was measured against higher temperatures to confirm their semiconductor nature. The findings demonstrated the typical decreasing trend with rising temperature.

Measuring magnetic hysteresis curves with polarized soft X-ray resonant reflectivity.

Calculations and measurements of polarization-dependent soft X-ray scattering intensity are presented during a magnetic hysteresis cycle. It is confirmed that the dependence of the intensity on the magnetic moment can be linear, quadratic or a combination of both, depending on the polarization of the incident X-ray beam and the direction of the magnetic moment. With a linearly polarized beam, the scattered intensity will have a purely quadratic dependence on the magnetic moment when the magnetic moment is parallel to the scattering plane. However, with the magnetic moment perpendicular to the scattering plane, there is also a linear component. This means that, when measuring the hysteresis with linear polarization during a hysteresis cycle, the intensity will be an even function of the applied field when the change in the magnetic moment (and field) is confined within the scattering plane but becomes more complicated when the magnetic moment is out of the scattering plane. Furthermore, with circular polarization, the dependence of the scattered intensity on the moment is a combination of linear and quadratic. With the moment parallel to the scattering plane, the linear component changes with the helicity of the incident beam. Surprisingly, in stark contrast to absorption studies, even when the magnetic moment is perpendicular to the scattering plane there is still a dependence on the moment with a linear component. This linear component is completely independent of the helicity of the beam, meaning that the hysteresis loops will not be inverted with helicity.

PVC plasticized membranes modified with Fe3O4 nanoparticles for potentiometric sensing of sulfate

Potentiometric sensing is one of the most wide spread platforms for analysis of aqueous solutions. The development of potentiometric sensors for hydrophilic anions such as sulfate, phosphate and bicarbonate is a challenging problem, since their high hydration energy results in a low affinity for non-polar polymer membranes – a standard material for potentiometric sensor production.In this study we propose a new type of polymeric sensor membranes for ion-selective sensors with pronounced selectivity to hydrophilic anions. The membranes are based on inorganic Fe3O4 nanoparticles (NP) embedded into plasticized poly(vinyl chloride). Six different formulations of membranes with various combinations of Fe3O4 nanoparticles and other membrane-active components were synthesized and characterized with a wide range of physico-chemical methods. Contact angle measurements, FTIR spectra, SEM and AFM imaging, magnetization hysteresis curves, ZFC/FC studies were performed. The obtained results proved the formation of nanocomposites and demonstrated a structure with “cavities” in membranes with embedded nanoparticles. Potentiometric sensitivity and selectivity of the developed sensors in aqueous solutions of SO42−, HPO42−, HCO3−, H2PO4−, NO3− and Cl−anions were studied. The developed sensors showed high sensitivity to sulfate ion (-22 mV/dec in the concentration range from 10−5 to 10−3 M) and low sensitivity to the typical interfering anions – chloride and nitrate (-14 mV/dec). The optimized sensor membrane composition demonstrated sulfate selectivity higher than that of commercially available ion-selective sensor formulations. The novel sensors were tested for quantification of SO42− in real samples of natural mineral water and the obtained content of sulfate was in a good agreement with the reference data (relative error < 3 %)

The structural and magnetic properties of Co0.9Ni0.1Fe2O4 as a heavy metal absorbing material

This research uses co-precipitation to synthesize cobalt nickel ferrite as a heavy metal absorbing material from natural iron sand. The co-precipitation method was applied with temperature calcination of 700 °C for 2 h. Characterization of crystal structure using X-ray diffraction (XRD), characterization of magnetic properties using Vibrating Sample Magnetometer (VSM), and characterization of particle morphology using Field Emission Scanning Electron Microscopes (FE-SEM). Characterization of adsorption capacity of samples using Atomic Absorption Spectrophotometer (AAS). From the characterization results, it is known that cobalt nickel ferrite is a hard magnet and has a cubic crystal structure. The magnetic hysteresis curve shows a coercivity of 715.68 Oe and a remanent magnetization of 18.38 emu/g. The absorption capacity obtained from Cu and Cr removal efficiency was 96.26%, with an adsorption capacity of 10.83 mg/L.

Designing bi-functional Ag-CoGd0.025Er0.05Fe1.925O4 nanoarchitecture via green method

In the current study, we developed a simple and biocompatible method for producing core–shell nanoparticles (NPs). Citrate auto combustion and green procedures were used to create core–shell Ag/CoGd0.025Er0.05Fe1.925O4 (Ag/CGEFO) sample with an average crystallite size of 26.84 nm. The prepared samples were characterized via different structural techniques, such as x-ray diffraction (XRD), Raman Spectroscopy (RS), High-Resolution Transmission Electron Microscopy, and Energy Dispersive x-ray analysis. These analyses were utilized to characterize and confirm the successful formation of the core–shell architecture. For core–shell NPs, all peaks of Ag and CGEFO ferrite are detected in the XRD, confirming the co-presence of the ferrite spinel phase and the cubic Ag phase. The magnetic hysteresis curves demonstrate typical hard ferri-magnetic behavior along with maximum magnetic saturation values up to 53.74 emu g−1 for the CGEFO sample, while an enhanced coercivity is detected for the coated sample. Moreover, the width of the hysteresis loop is increased for the Ag/CGEFO sample compared to the uncoated one. This indicates that the addition of Ag as a shell increases magneto crystalline anisotropy. Moreover, the E g of uncoated CGEFO is equal to 1.4 eV, increasing to 3.6 eV for coated ones. This implies the influence of CGEFO is diminished when the surface is coated with Ag (shell), and the reflectance of the Ag/CGEFO core–shell is nearly dependent on the reflectance of the Ag shell layer. Consequently, the Ag/CGEFO can be used as a light shielding substance.

The influence of the cluster connection modes on the soft magnetic properties in the Fe78Si9B13 amorphous ribbon

The structures and magnetic properties of Fe78Si9B13 amorphous ribbons were detected after annealing at different temperatures. Compared with the clusters in the FeB amorphous alloy, the second shell of BB coordination is replaced by SiB coordination in the clusters of the Fe78Si9B13 amorphous alloy. The interaction between Fe and B atoms is strengthened at a higher annealing temperature. Based on the Gaussian decomposition toward the splitting second peaks in g(r) curves, the shared connection modes of the clusters have been obtained. The main connection modes between the clusters of all the samples are the three-atom-shared connection and the one-atom-shared connection. With the increasing annealing temperature, the three-atom-shared connection is enhanced, and the one-atom-shared connections are weakened. Combined with the results of the magnetic hysteresis curves, it is found that the enhancement of the three-atom-shared connection is responsible for the increase of the saturation magnetization.

Influence of Ce3+ ion doping on structural, morphological, magnetic, dielectric and optical properties of Mg0.5Ni0.5Fe2-xCexO4 (0 ≤ x ≤ 0.1) ferrite nanoparticles synthesized via coprecipitation method

In this work the effect of Ce3+ ion doping on microstructure, crystallite size, magnetic, optical and dielectric characteristics of Mg0.5Ni0.5Fe2-xCexO4 (0 ≤ x ≤ 0.1) ferrite nanoparticles are discussed which are synthesized by using the co-precipitation method. The X-ray diffraction analysis confirms the cubic phase of all the synthesized samples and further confirmation of ferrite structure is supported by Fourier transformed infrared spectroscopy characteristic peaks. The crystallite size was determined in the range of 6 nm to 12 nm with increasing lattice parameter value from 8.347 Å to 8.359 Å on increasing Ce3+ ion doping. High-resolution transmission electron microscopy analysis confirms the spherical shape of the nanoparticles with agglomeration. Magnetic hysteresis curves analysis reveals that saturation magnetization of the Mg-Ni ferrite nanoparticles decreases with increasing Ce3+ ion concentration. Vibrating sample magnetometer analysis confirms the superparamagnetic nature of the synthesized samples. Electron spin resonance spectroscopy confirmed the reduction in g-value and spin relaxation time with increasing Ce3+ ions doping. The band gap increases from 1.79 eV to 2.59 eV with increasing Ce3+ ion doping. The magnetic properties of the synthesized samples make these nanoparticles a potential candidate for the synthesis of ferrofluids and biomedical application. Dielectric study confirms the decrease in dielectric constant (ε′) and loss tangent (tan δ) against increasing frequency with increasing Ce3+ ion concentration making the nanoparticles a potential candidate for the high frequency applications.

The thermo-therapeutic applications of Chitosan- CTAB coated Nickel Ferrite (NiFe2O4) magnetic nanoparticles

In this study, we used a hydrothermal-assisted co-precipitation method to synthesize the nickel ferrite (FN), Chitosan coated nickel ferrite (FN-Ch) and cetyltrimethylammonium bromide coated nickel ferrite (FN-CT) nanoparticles with small sizes and good biocompatibility. These nanoparticles were then evaluated for their potential use in magnetic hyperthermia. The particles were characterized using a variety of techniques, including x-ray diffraction, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA), Inductively coupled plasma (ICP), magnetic characterization (VSM), zeta potential analysis, and in vivo studies (blood hemolysis and MTT test). The results of the x-ray diffraction analysis showed that the nanoparticles had a spinel phase of NiFe2O4. TEM analysis revealed that all three samples contained particles with nearly quadrilateral and hexagonal shapes. FT-IR spectroscopy confirmed the presence of Chitosan and CTAB coatings on the particle surface. Magnetic hysteresis curves showed that all of the synthesized samples exhibited superparamagnetic behavior at room temperature. The findings from the ICP analysis indicated that the FN-Ch and FN-CT nanoparticles contained iron and nickel, while no substantial quantities of other trace elements were identified in either of the samples. Blood hemolysis and MTT tests were used to assess the toxicity of the nanoparticles when in contact with red blood cells, fibroblast cells, and MCF7 cancer cells. Overall, our findings suggest that FN-Ch and FN-CT nanoparticles have potential for use in cancer diagnosis and treatment as part of a new nano-carrier system. Furthermore, combining hyperthermia with other treatment methods could enhance the effectiveness of cancer therapy.