Mahmoud Goodarz Naseri

Simple synthesis and characterization of cobalt ferrite nanoparticles by a thermal treatment method

Crystalline, magnetic, cobalt ferrite nanoparticles were synthesized from an aqueous solution containing metal nitrates and polyvinyl pyrrolidone (PVP) as a capping agent by a thermal treatment followed by calcination at various temperatures from 673 to 923 K. The structural characteristics of the calcined samples were determined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). A completed crystallization occurred at 823 and 923 K, as shown by the absence of organic absorption bands in the FT-IR spectrum. Magnetization measurements were obtained at room temperature by using a vibrating sample magnetometer (VSM), which showed that the calcined samples exhibited typical magnetic behaviors.

An Overview on Nanocrystalline ZnFe2O4, MnFe2O4, and CoFe2O4 Synthesized by a Thermal Treatment Method

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn, and Co) nanoparticles by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidone) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle sizes were obtained by TEM images, which were in good agreement with the XRD results. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited superparamagnetic and ferromagnetic behaviors.

The amazing effects and role of PVP on the crystallinity, phase composition and morphology of nickel ferrite nanoparticles prepared by thermal treatment method

Nickel ferrite nanocrystals were prepared from an aqueous solution containing metal nitrates and various concentrations of poly(vinylpyrrolidone) followed by calcination temperature. X-ray diffraction (XRD) analysis was performed to determine the degree of crystallinity of the ferrite nanoparticles. By transmission electron microscopy, the morphology and average particle size of the nickel ferrite nanoparticles were evaluated which had good agreement with the XRD results. Fourier transform infrared spectroscopy suggested the presence of metal oxide bands in all samples as well as the effective elimination of organic constituents after calcinations. Measurements of the extent of magnetization of the nickel ferrite nanoparticles synthesized in different concentrations were obtained at room temperature using a vibrating sample magnetometer.

Silver Nanoparticle Fabrication by Laser Ablation in Polyvinyl Alcohol Solutions

A laser ablation technique is applied for synthesis of silver nanoparticles in different concentrations of polyvinyl alcohol (PVA) aqueous solution. The ablation of high pure silver plate in the solution is carried out by a nanosecond Q-switched Nd:YAG pulsed laser. X-ray diffraction and transmission electron microscopy are implemented to explore the particles sizes. The effects of PVA concentrations on the absorbance of the silver nanoparticles are studied as well, by using a UV-vis spectrophotometer. The preparation process is carried out for deionized water as a reference sample. The comparison of the obtained results with the reference sample shows that the formation efficiency of nanoparticles in PVA is much higher and the sizes of particles are also smaller.

The effects and roles of PVP on the phase composition, morphology and magnetic properties of cobalt ferrite nanoparticles prepared by thermal treatment method

Cobalt ferrite nanocrystals were prepared from an aqueous solution containing metal nitrates and various of concentrations of poly(vinyl pyrrolidone), followed by calcinations temperature. X-ray diffraction (XRD) analysis was performed to determine the degree of crystallinity of the ferrite nanoparticles. By transmission electron microscopy (TEM), the morphology and average particle size of the cobalt ferrite nanoparticles were evaluated which had good agreement with XRD results. Fourier transform infrared spectroscopy (FT-IR) suggested the presence of metal oxide bands in all samples as well as the effective elimination of organic constituents after calcinations. Vibrating sample magnetometer (VSM), was utilized to evaluate the magnetic properties of the cobalt ferrite nanoparticles.

Crystalization in Spinel Ferrite Nanoparticles

The enhanced interest of the researchers in nanoobjects is due to the discovery of unusual physical and chemical properties of these objects, which is related to manifestation of so-called ‘quantum size effects‘. These arise in the case where the size of the system is commensurable with the de-Brogli wavelengths of the electrons, phonons or excitons propagating in them.A key reason for the change in the physical and chemical properties of small particles as their size decreases is the increased fraction of the surface atoms, which occur under conditions (coordination number, symmetry of the local environment, etc.) differing from those of the bulk atoms. From the energy standpoint, a decrease in the particle size results in an increase in the fraction of the surface energy in its chemical potential [1]. Currently, unique physical properties of nanoparticles are under intensive research [2]. A special place belongs to the magnetic properties in which the difference between a massive (bulk) material and a nanomaterial is especially pronounced.The magnetic properties of nanoparticles are determined by many factors, the key of these including the chemical composition, the type and the degree of defectiveness of the crystal lattice, the particle size and shape, the morphology (for structurally inhomogeneous particles), the interaction of the particle with the surrounding matrix and the neighbouring particles. By changing the nanoparticle size, shape, composition and structure, one can control to an extent the magnetic characteristics of the material based on them. However, these factors cannot always be controlled during the synthesis of nanoparticles nearly equal in size and chemical composition; therefore, the properties of nanomaterials of the same type can be markedly different [1].Apart from these factors, the magnetic properties of particles depend on the external conditions: temperature, pressure and, in some cases, the local environment, i.e., the medium in which the particle occurs, in particular, the crystalline or amorphous bulk matrix (for a particle), the local crystal environment (for a single atom) or the substrate (for a film).

Effect of phase transformation on physical and biological properties of PVA/CaFe2O4 nanocomposite

The thermal treatment method was employed to achieve higher homogeneity of calcium ferrite (CaFe2O4) and Poly (vinyl alcohol) (PVA) nanocomposites. The influences of phase transformation on physical and biological properties of calcined specimens were investigated by various experimental techniques including X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), high resolution Field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FT-IR). Heat treatment was conducted at temperatures between 723 and 923 K, so that a phase transformation occurred from cubic to orthorhombic spinel structure at 923 K. The chemical analysis of the PVA/CaFe2O4 nanocomposite was performed by energy dispersion X-ray analysis (EDXA), demonstrated the PVA/CaFe2O4 nanocomposites contained the elements of C, Ca, Fe, and O. The formed nanocomposites exhibited ferromagnetic behaviors which were confirmed by using a vibrating sample magnetometer (VSM). The calcined specimens were carried out to an antimicrobial or antifungal test.

A simple thermal treatment synthesis and characterization of Ni-Zn ferrite (Ni0.5Zn0.5Fe2O4) nanocrystals

Cubic structured nickel-zinc ferrite nanoparticles (Ni0.5Zn0.5Fe2O4) have been synthesized by thermal treatment method. This simple procedure employed an aqueous solution containing only metal nitrates as precursors, polyvinyl pyrrolidone as a capping agent, and deionized water as a solvent. The solution was thoroughly stirred for 2 hour, dried at 353 K for 3 hour, the dried material crushed into powder and calcined the powder at 873 K to remove organic substances and crystallize the particles. The microstructure properties of the prepared ferrite nanoparticles were measured using FTIR, XRD, TEM, and EDX and the magnetic properties were determined using VSM and EPR. The average particle size increased from 7 to 22 nm with the increase of calcination temperature from 723 to 873 K. The saturation magnetization, coercivity field, and g- factor increased respectively from 24 emu/g, 11 G, and 2.0673at 723 K to 38 emu/g, 60 G, and 2.1227 at 873 K. This method offers simplicity, a low cost, and an environmentally friendly operation since it produces no by- product effluents.

Preparation and Characterization of NiCoFerrite Nanoparticles by Thermal Method

The NiCoFerrite nanoparticle has been prepared using thermal method. Polyvinyl pyrrolidon (PVP) was used as a reducing agent due to its reducing effect on agglomeration of particles. The characterization studies such as X-ray diffraction (XRD) and transmission electron microscopy (TEM) have been done for explore the particles size. By Scherers equation the average particles size has been estimated that support TEM results. An increasing in particles size was observed with increasing calcinations temperature. FTIR confirmed the presence of metal oxide.