The magnetic properties of magnetic nanoparticles produced by microwave flash synthesis of ferrous alcoholic solutions

Summary form only given. Microwave heating is an emerging technology, which uses the ability of some liquids and solids to transform electromagnetic energy into heat. Recently it has been shown that it is possible to produce hematite, magnetite and iron-magnetite nanoparticles by microwave heating of alcoholic solutions of a ferrous salt. The developed original microwave applicator associated with autoclave for one flash synthesis of nanoparticles by disproportionation of ferrous alcoholic solutions as well as operation conditions is described elsewhere Caillot et al. (Journ. of Mat. Sci. (2002)). We present the results of experimental study of magnetic and structural properties of magnetic nanoparticles fabricated by this technique. Comparing with similar nanoparticles fabricated by using a conventional heating, we obtained much lower grain size (up to 10 nm) and very stable properties. The hysteresis loop for samples of the non-oriented assembly of hematite particles has a coercive force about 100 Oe with squareness about 0.4. Some quantity of superparamagnetic fraction exists in our sample. The particles distribution on the anisotropy fields has a maximum about 200 Oe. The possibility of improvement of the magnetic properties is under investigation.