Based on a self-assembly strategy, spherical mesoporous cobalt and nickel ferrite nanocrystal clusters with a large surface area and narrow size distribution were successfully synthesized for the first time via a template-free solvothermal process in ethylene glycol and subsequent heat treatment. In this work, the mesopores in the ferrite clusters were derived mainly from interior voids between...

The square arrays are fabricated by e-beam lithography on polycrystalline Co sputtered on glass substrates. First, a continuous layer, 1000 nm thick, of polycrystalline Co is grown. This thickness guarantees optical opacity for the light used in the experiments, a 632.8 nm wavelength 1.5 mW laser. Secondly, the continuous Co layer is locally etched (all the way through to the glass substrate) t...

Recent advances in the synthesis of various magnetic nanoparticles using colloidal chemical approaches are reviewed. Typically, these approaches involve either rapid injection of reagents into hot surfactant solution followed by aging at high temperature, or the mixing of reagents at a low temperature and slow heating under controlled conditions. Spherical cobalt nanoparticles with various crys...

Cobalt-doped magnetite (CoxFe3 -xO4) nanoparticles have been produced through the microbial reduction of cobalt-iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt c...

Monodisperse iron oxide nanocrystals were synthesized by a simplified method using iron chloride as precursor. In the presence of Cl ions, the as-produced iron oxide nanocrystals preferred a cubic shape with {100} facets exposed. The function of halogens including Cl and Br ions on stabilizing {100} facets of spinel structured iron oxides, rather than the regulation of thermolysis kinetics and ...

magnetic cofe2o4 nanoparticles were synthesized via a simple chemical reaction using precipitation method. the obtained materials consist of ferrite particles with average diameter of 25 nm. the effect of different surfactants such as cationic, anionic and neutral on the morphology of the products was investigated. scanning electron microscopy was used to study the structure and particle size o...