Low temperature hydrothermal synthesis and characterization of Mn doped cobalt ferrite nanoparticles

Synthesis of Fe3O4 nanoparticles at 100 °C and its magnetic characterization

Hybrid nanomaterials have received voluminous interest due to the combination of unique properties of organic and inorganic component in one material. In this class, magnetic polymer nanocomposites are of particular interest because of the combination of excellent magnetic properties, stability, and good biocompatibility. Organic–inorganic magnetic nanocomposites can be prepared by in situ, ex situ, microwave reflux, co-precipitation, melt blending, and ceramic–glass processing and plasma polymerization techniques. These nanocomposites have been exploited for in vivo imaging, as superparamagnetic or negative contrast agents, drug carriers, heavy metal adsorbents, and magnetically recoverable photocatalysts for degradation of organic pollutants. This review article is mainly focused on fabrication of magnetic polymer nanocomposites and their applications. Different types of magnetic nanoparticles, methods of their synthesis, properties, and applications have also been reviewed briefly. The review also provides detailed insight into various types of magnetic nanocomposites and their synthesis. Diverse applications of magnetic nanocomposites including environmental and biomedical uses have been discussed.

Magnetic polymer nanocomposites for environmental and biomedical applications

Structural and magnetic properties of CoxZn1−xFe2O4 nanocrystals synthesized by microwave method

Synthesis and characterization of CoxZn1−xFe2O4 magnetic nanoparticles via a PEG-assisted route

Superparamagnetic nanoparticles of magnetite (Fe 3 O 4 ) 2 nm in size were produced by a co-precipitation method. Superparamagnetic resonance (SPR) spectra at room temperature show a broad line with a Lande g-factor, g eff ≈ 2. It was observed that, as the temperature decreased to 24 K, the apparent resonance field decreases while the line width considerably increases. We used a theoretical formalism based on a distribution of diameters or volumes of the nanoparticles. The nanoparticles behave as single magnetic domains with random orientations of magnetic moments which are subject to thermal fluctuations. A Landau-Lifshitz line shape function presents adequate results which are in good agreement with the experimental ones. A single set of parameters provides good fits to the spectra recorded at different temperatures. At high T the SPR line shape is governed by the core anisotropy and the thermal fluctuations. By decreasing the temperature, the magnetic susceptibility of shell spins increases. As a result of this, the surface spins produce an effective field on the core leading to a decrease of resonance field, B r . Also, the effective anisotropy increases as the shell spins begin to order. So, the results are interpreted by a simple model, in which each single-domain nanoparticle is considered as a core-shell system, with magnetocrystalline anisotropy on the core and surface anisotropy on the shell.

and B. Aktaş

Papers

Surface effects on magnetic properties of superparamagnetic magnetite nanoparticles