Magnetic nanocomposites are an important class of advanced functional materials on the basis of a magnetic material and a matrix. To achieve unique mechanical, physical, chemical, and biomedical properties, one must be able to tailor only the surface structures of a nanoparticle. This requires the deposition of ultrathin and uniform films using the possibility offered by cold-plasma polymerisat...

Iron cobaltite powders CoxFe3ÿxO4 (1rxr2.46) were synthesized with compositions in between the cobalt ferrite CoFe2O4 and Co2.46Fe0.54O4. The cationic distribution of pure spinel phases was determined by Mössbauer spectroscopy: as Co content increases in the spinel oxide, Co cations replace Fe cations in the octahedral sites and Co cations migrate from octahedral to tetrahedral sites. Saturatio...

Nickel-substituted cobalt ferrite–reduced graphene oxide (NCF-RGO) composite was synthesized using a facile one-pot chemical coprecipitation method. The addition of (GO) leads to the decrease in size NCF nanoparticles (< 10 nm) present nanocomposite, which plays role controlling their magnetic and dielectric properties. Nickel with lower ionic radius compared cobalt, its substitution along inco...

The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measure...

....................................................................................................................................... ix Chapter 1: Introduction ........................................................................................................ 1 1.1 General Introduction ........................................................................................... 1 1.2 Moti...

The temperature variation of magnetic anisotropy and coercive field of magnetoelastic manganese-substituted cobalt ferrites CoMnxFe2−xO4 with 0 x 0.6 was investigated. Major magnetic hysteresis loops were measured for each sample at temperatures over the range 10–400 K, using a superconducting quantum interference device magnetometer. The high-field regimes of the hysteresis loops were modeled ...

Cobalt substitutions were investigated in Ni0.4Zn0.4Cu0.2Fe2O4 ferrites, initial complex permeability was then measured from 1 MHz to 1 GHz. It appears that cobalt substitution led to a decrease of the permeability and an increase of the μs×fr factor. As well, it gave to the permeability spectrum a sharp resonance character. We also observed a spin reorientation occuring at a temperature depend...

Standard approaches to investigate the anisotropy of nanoparticle assemblies are either by means zero-field-cooled–field-cooled DC magnetization curves or analyzing coercivity at low temperatures. However, these methodologies restricted average values an constant, without probing its temperature dependence symmetry. In this context, thermal arises as a more comprehensive approach assess anisotr...

In this work, we investigated synthesis, magnetic properties of silica coated metal ferrite, (CoFe2O4)/SiO2 and Manganese doped cobalt ferrite nanoparticles (MnxCo1-xFe2O4 with x= 0.02, 0.04 and 0.06)/SiO2 for possible biomedical application. All the ferrites nanoparticles were prepared by co-precipitation method using FeCl3.6H2O, CoCl2.6H2O and MnCl2.2H2O as precursors, and were silica coated ...

A weak surface modification is applied to Co/SiO2 catalyst by hydrothermal treatment at 180°C for 5 h. Aluminum is introduced to Co/SiO2 catalysts during the surface modification. The effects of surface modification on Co/SiO2 catalyst are studied by changing the operating sequences of surface modification and cobalt impregnation in the catalyst preparation. Surface modification before cobalt i...