Analysis of Spectroscopic, Optical and Magnetic Behaviour of PVDF/PMMA Blend Embedded by Magnetite (Fe₃O₄) Nanoparticles

In the present work, magnetite (Fe3O4) nanoparticles have been prepared by a simple chemical method. Polymer nanocomposites based on the blend between poly vinylamine fluoride (PVDF) and (methyl methacrylate) (PMMA) doped with different concentrations of Fe3O4 nanoparticles have been prepared. The structural, optical, and magnetization properties of the nanocomposite samples were studied using suitable techniques. The X-ray study reflected that the cubic spinal structure of pure Fe3O4 crystal. No small peaks or ripples were found in the X-ray spectra, conforming to good dispersion of Fe3O4 within PVDF/PMMA matrices. The FT-IR analysis demonstrated the miscibility between the PVDF and PMMA blend with the interaction between the polymer blend and Fe3O4. The values of the band gap from UV-Vis study were decreased up to 4.21 eV, 3.01 eV for direct and indirect measurements, respectively. The magnetization was measured as a function of the applied magnetic field in the range of −2000 - 2000 Oersted. The curves of the magnetization indicated a paramagnetic behavior of pure Fe3O4 nanoparticles and PVDF/PMMA-Fe3O4 nanocomposites. The values of saturation magnetization for pure Fe3O4 are nearly 75 emu/g, exhibiting a paramagnetic behavior, and it is decreased with the increase of Fe3O4 content.

Surface modification of Fe_3O_4 nanoparticles and their magnetic properties

Fe3O4 magnetic nanoparticles were synthesized by the hydrothermal method, and the influences of the surfactant sodium bis（2-ethylhexyl） sulfosuecinate （AOT） on the particles were investigated. The structure, morphology, and magnetic properties of the products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FT-IR）, and vibrating sample magnetometer （VSM）. It is confirmed that the as-prepared nanoparticles have been modified by using the surfactant during the synthesis process. The amount of the surfactant has an effect on the size, the dispersal, and the magnetic properties of the particles. Besides, the mechanisms of the influences were also discussed.

Monodisperse magnetic metallic nanoparticles: synthesis,performance enhancement, and advanced applications

Monodisperse Fe-based and Co-based nanopar-ticles exhibit unique magnetic properties. They play important roles in magnetic storage and biomedical application. Their chemical synthesis and performance enhancement draw a lot of study interest. Investigations of magnetic metallic nano-particles are very active in many scientific fields. This paper reviews the present advances in chemical synthesis, perfor-mance enhancement, and potential applications of monodis-perse Fe-based and Co-based nanoparticles.

Dielectric and magnetic properties of(Zn, Co) co-doped SnO_2 nanoparticles

Polycrystalline samples of（Zn, Co） co-doped SnO2 nanoparticles were prepared using a co-precipitation method. The influence of（Zn, Co） co-doping on electrical, dielectric, and magnetic properties was studied. All of the（Zn, Co） co-doped SnO2 powder samples have the same tetragonal structure of SnO2. A decrease in the dielectric constant was observed with the increase of Co doping concentration. It was found that the dielectric constant and dielectric loss values decrease, while AC electrical conductivity increases with doping concentration and frequency. Magnetization measurements revealed that the Co doping SnO2 samples exhibits room temperature ferromagnetism. Our results illustrate that（Zn, Co） co-doped SnO2 nanoparticles have an excellent dielectric, magnetic properties, and high electrical conductivity than those reported previously, indicating that these（Zn, Co） co-doped SnO2 materials can be used in the field of the ultrahigh dielectric material, high frequency device, and spintronics.

Dysprosium Modification of Cobalt Ferrite Ionic Magnetic Fluids

Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows that magnetic response toward exterior magnetic field can be improved by adding Dy3+. Studies also show that the increase of reaction temperature may improve the modification effect of dysprosium. By adding dysprosium ions, the average diameter of the magnetic nanoparticles will be decreased evidently. It is clear that the particles appear as balls. Cobalt ferrite with sizes of 12-15 nm, rare earth composite cobalt ferrite with sizes of 6-8 nm.

Nanosized As_2O_3/Fe_2O_3 complexes combined with magnetic fluid hyperthermia selectively target liver cancer cells

AIM:To study the methods of preparing the magnetic nano-microspheres of Fe2O3 and As2O3/Fe2O3 complexes and their therapeutic effects with magnetic fluid hyperthermia(MFH). METHODS:Nanospheres were prepared by chemical co-precipitation and their shape and diameter were observed.Hemolysis,micronucleus,cell viability,and LD50 along with other in vivo tests were performed to evaluate the Fe2O3 microsphere biocompatibility.The inhibition ratio of tumors after Fe2O3 and As2O3/Fe2O3 injections combined with induced hyperthermia in xenograft human hepatocarcinoma was calculated. RESULTS:Fe2O3 and As2O3/Fe2O3 particles were round with an average diameter of 20 nm and 100 nm as observed under transmission electron microscope.Upon exposure to an alternating magnetic field(AMF),the temperature of the suspension of magnetic particles increased to 41-51℃,depending on different particle concentrations,and remained stable thereafter.Nanosized Fe2O3 microspheres are a new kind of biomaterial without cytotoxic effects.The LD50 of both Fe2O3 and As2O3/Fe2O3 in mice was higher than 5 g/kg.One to four weeks after Fe2O3 and As2O3/Fe2O3 complex injections into healthy pig livers,no significant differences were found in serum AST,ALT,BUN and Cr levels among thepigs of all groups(P>0.05),and no obvious pathological alterations were observed.After exposure to alternating magnetic fields,the inhibition ratio of the tumors was significantly different from controls in the Fe2O3 and As2O3/Fe2O3 groups(68.74% and 82.79%,respectively; P<0.01).Tumors of mice in treatment groups showed obvious necrosis,while normal tissues adjoining the tumor and internal organs did not. CONCLUSION:Fe2O3 and As2O3/Fe2O3 complexes exerted radiofrequency-induced hyperthermia and drug toxicity on tumors without any liver or kidney damage. Therefore,nanospheres are ideal carriers for tumortargeted therapy.

Synthesis and Characterization of Superparamagnetic Fe₃O₄@SiO₂Core-Shell Composite Nanoparticles

The Fe3O4@SiO2 composite nanoparticles were obtained from as-synthesized magnetite (Fe3O4) nanoparticles through the modified St?ber method. Then, the Fe3O4 nanoparticles and Fe3O4@SiO2 composite nanoparticles were characterized by means of X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Recently, the studies focus on how to improve the dispersion of composite particle and achieve good magnetic performance. Hence effects of the volume ratio of tetraethyl orthosilicate (TEOS) and magnetite colloid on the structural, morphological and magnetic properties of the composite nanoparticles were systematically investi-gated. The results revealed that the Fe3O4@SiO2 had better thermal stability and dispersion than the magnetite nanoparticles. Furthermore, the particle size and magnetic property of the Fe3O4@SiO2 composite nanoparticles can be adjusted by changing the volume ratio of TEOS and magnetite colloid.

Synthesis, characterization and magnetic properties of KFeO_(2) nanoparticles prepared by a simple egg white solution route

Nanoparticles of potassium ferrite(KFeO_(2))in this work were synthesized by a simple egg white solution method upon calcination in air at 773,873,and 973 K for 2 h.The effects of calcination temperature on the structural and magnetic properties of the synthesized KFeO_(2) nanoparticles were investigated.By varying the calcination temperature,X-ray diffraction and transmission electron microscopy results indicated the changes in crystallinity and morphology including particle size,respectively.Notably,the reduction in particle size of the synthesized KFeO_(2) was found to have a remarkable influence on the magnetic properties.At room temperature,the synthesized KFeO_(2) nanoparticles prepared at 873 K exhibited the highest saturation magnetization(M_(S))of 2.07×10^(4) A·m^(−1).In addition,the coercivity(H_(C))increased from 3.51 to 16.89 kA·m^(−1) as the calcination temperature increased to 973 K.The zero-field cooled(ZFC)results showed that the blocking temperatures(T_(B))of about 125 and 85 K were observed in the samples calcined at 773 and 873 K,respectively.Therefore,this work showed that the egg white solution method is simple,cost effective,and environmentally friendly for the preparation of KFeO_(2) nanoparticles.

Fabrication of a Magnetite Nanoparticle-loaded Polymeric Nanoplatform for Magnetically Guided Drug Delivery

We developed a magnetite nanoparticle-loaded polymeric nanoplatform for magnetically guided 10- hydroxycamptothecin（HCPT） delivery. The nanoplatform was fabricated by simultaneously incorporating magnetite nanoparticles（NPs） and HCPT into the polymer micelle self-assembled from methoxy polyethylene glycolpoly（D,L-lactide-co-glycolide）（MPEG-PLGA） copolymer. Successful loading of HCPT into the nanoplatform was confirmed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, we examined the in vitro antitumor efficacy of free HCPT and nanoplatform against three different cancer cell lines HeLa, A549 and HepG2. Flow cytometric analysis was condkt ,ucted to reveal the cell apoptosis caused by free HCPT and nanoplatform. Finally, the magnetic targeting property of the nanoplatform was evaluated by a self-designed in vitro experiment.

Synthesis and Soft Magnetic Properties of Mg-doped Ni Nanoparticles

Mg-doped Ni nanoparticles with good soft magnetic properties were prepared with the sol-gel method and were sintered at 400, 500, 600, and 900℃ in argon atmosphere, respectively. The structure and magnetic properties of the samples were studied by means of X-ray diffraction, TEM, and VSM magnetometers. X-Ray powder diffraction results show that Ni-Mg solid solution was formed with the single phase of face-centered cubic（fcc） structure. The particle size became larger with the increase of temperature. When the sintering temperature was 400 °C, the particle size was 6.3 nm, whereas it was 46.2 nm at 900 °C. Both the saturation magnetization（Ms） and the coercivity were enhanced with the increase of the particle size. The Ms values of the samples ranged from 18.965 to 46.766 emu/g and the coercivity ranged from 1051.3568 to 9145.0848 A/m.

Controllable Synthesis and Magnetic Properties of Monodisperse Fe_3O_4 Nanoparticles

Magnetite （Fe3O4） nanoparticles with different sizes and shapes are synthesized by the thermal decomposition method. Two approaches, non-injection one-pot and hot-injection methods, are designed to investigate the growth mechanism in detail. It is found that the size and shape of nanoparticles are determined by adjusting the precursor concentration and duration time, which can be well explained by the mechanism based on the LaMer model in our synthetic system. The monodisperse Fe3O4 nanoparticles have a mean diameter from 5nm to 16nm, and shape evolution from spherical to triangular and cubic. The magnetic properties are size-dependent, and Fe3O4 nanoparticles in small size about 5 nm exhibit superparamagnetie properties at room temperature and maximum saturation magnetization approaches to 78 emu/g, whereas Fe3O4 nanoparticles develop ferromagnetic properties when the diameter increases to about 16nm.

Enhanced Magnetic and Dielectric Properties in Low-Content Tb-Doped BiFeO3 Nanoparticles

Bi1-xTbxFeO3 （x = 0, 0.01, 0.03 and 0.05） nanoparticles are synthesized by the sol-gel method. A single phase perovskite rhombohedral structure of all the samples is established from the Rietveld refined XRD patterns. The substitution of Tb^3＋ ions to Bi^3＋ decreases the particle size and enhances the ferromagnetic properties of this system. Interestingly a large maximum magnetization value of 1.73emu/g at 50kOe can be observed in 1% Tb-doped sample at 300 K. The decrease in band gap may result from the reduced particle size, while the leakage current density also decreases, which is mainly explained by the variation of oxygen vacancies.

Abugomry Induction Heater Design to Study the Thermal Properties of Magnetic Nanoparticles

In this project a new simple induction heater design （Abugomry） operated at low power and low frequency 100w/100kHz was made. The thermal properties of three different MNPs （magnetic nano particles） were studied by Abugomry induction heater. The high temperatures of MNPs （47, 46 and 50） ℃, the heating rate （0.030, 0.025 and 0.028） ℃/min and the specific absorption rate （126, 115 and 105） W/g for the （α-Fe2O3, Fe3O4 and CoFe2O4） MNPs respectively, these results were suitable to use these MNPs in MHT （magnetic hyperthermia treatment）. The results accrue from Abugomry of these MNPs that it＇s agree with the published results of the same MNPs, which were studied by induction heater operated at high/medium power and frequency.

Response of self-assembly for magnetite nanocrystal in magnetic fluid under an applied magnetic field

The response time and transmittivity of the magnetic fluid （MF） for different concentrations at room temperature were investigated in this letter. The volume fraction of the investigated sample ranged from 0.44% to 6.47%. It was found that the transmittivity decreased with increasing concentration under a given magnetic field, and the evolution time was changed with different concentrations. Moreover the light intensity decreased rapidly at the beginning and then became stable when the magnetic field was applied.

Growth of Magnetite Nanoparticles under Magnetic Fields

1 Introduction Over the past several years, the preparation and characterization ofnanoscale magnetic materials, especially one-dimensional (1D) nanostructure, have attracted much attention as the nanomaterials would allow investigating the fundamental aspects of magnetic-ordering phenomena in magnetic materials with reduced dimensions and could lead to new potential applications such as data storage technology[1-6].……

Structure and magnetic properties of Cu-Ni alloy nanoparticles prepared by rapid microwave combustion method

Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and VSM. XRD and EDX analyses suggest the formation of pure alloy powders. The average crystallite sizes were found to be in the range of 21.56-33.25 nm. HR-SEM images show the clustered/agglomerated particle-like morphology structure. VSM results reveal that for low Ni content （CusNis, Cu6Ni4 and Cu7Ni3）, the system shows paramagnetic behaviors, whereas for high Ni content （Cu3Ni7 and Cu4Ni6）, it becomes ferromagnetic.

Magnetic Properties of Ni Nanoparticles and Ni(C) Nanocapsules

Structure and magnetic properties of Ni nanoparticles and Ni(C) nanocapsules were studied. The carbon atoms hardly affect the lattice of Ni to form Ni-C solid solution or nickel carbides. The large thermal irreversibility in zero-field-cooled and zero-field magnetization curves indicates magnetic blocking with a wide energy barrier. Saturation magnetization, remanent magnetization and coercivity of Ni(C) nanocapsules decrease with increasing temperature.

Synthesis and Properties of Magnetic Nanoparticles

The uniform mesoporous SBA-15 consisting of SiO2 with long-range channels Offers an excellent host material to synthesize or assemble the magnetic nanocomposites, such as Fe, Ni. In this paper, highly dispersed and uniform iron nanoparticles were incorporated into the pore channels of SBA-15 through a newly developed strategy in which some kinds of coupling agents were used to entrap the nanoparticles into the silica framework. The X-ray diffraction （XRD）, fourier transmission infrared spectroscopy （FTIR）, high-resolution transmission electronic microscopy （HRTEM） and energy dispersive X-ray spectroscopy （EDX） were performed to further identify the successful incorporation and grafting of iron. Compared with other ordinary non-assembled magnetic nanoparticles, the assembled Fe nanoparticles with the diameter even in the size range of 5～6 nm still have better magnetic properties.

Saturation Magnetization and Law of Approach to Saturation for Selfformed Ionic Ferrofluids Based on MnFe2O4 Nanoparticles

The magnetization curves of MnFe2O4 nanoparticles and self-formed ferrofluids based on these particles have been measured at room temperature. The median size of the particles is 13.67 nm. The specific saturation magnetization is less than the theoretical value for the ferrofluids. In the high field range from 5 kOe to 10 kOe, the higher the particle volume fraction is, the steeper the slope of the magnetization curves is when it approaches saturation. The behavior of the saturation magnetization and the law of approach to saturation are due to the presence of self-assembled aggregates of ring-like micelle structures which form in the absence of the magnetic field and field-induced aggregates, respectively. The field-induced aggregates have a dissipative structure, so that at high field, the law of approach to saturation magnetization is different from the one described using Langevin paramagnetism theory. The large particles in the ferrofluids result in apparent hysteresis.

Mechanical and magnetocaloric adjustable properties of Fe3O4/PET deformed nanoparticle film

The flexibility of nanoparticle films is a topic of rapidly growing interest in both scientific and engineering researches due to their numerous potential applications in a broad range of wearable electronics and biomedical devices.This article presents the elucidation of the properties of nanoparticle films.Here,a flexible film is fabricated based on polyethylene terephthalate(PET)and magnetic iron oxide at the nanoscale using layer-by-layer technology.The 2D thin flexible film material can be bent at different angles from 0°to 360°.With an increase in elastic deformation angles,the magnetocaloric effect of the film gradually increases in the alternating magnetic field.The test results from a vibrating sample magnetometer and a low-frequency impedance analyzer demonstrate that the film has a good magnetic response and anisotropy.The magnetocaloric effect and magnetic induction effect are controlled by deformation,providing a new idea for the application of elastic films.It combines the flexibility of the nanoparticle PET substrate and,in the future,it may be used for skin adhesion for administration and magnetic stimulation control.