Formation of stable magnetic nanoparticles by pyrolysis of metal containing polymers

Abstract Inorganic matrix magnetic nanocomposite, containing Fe 3 C nanocrystallites, was processed by an innovative fabrication method using frontal polymerisation of iron acrylamid complex (FeAAm), followed by further pyrolysis at 873 K/150 min. The pyrolysis product was in a form of porous, irregular powder particles having broad range of size distribution, from 50 up to 500 μm. The powder particles contain nanocrystallites of Fe 3 C having mean size 10–80 nm. The plot of magnetisation versus external magnetic field is characteristic of ferromagnetic material with well-defined hysteresis loops. Saturation magnetisation is 40 emu/g and slightly depends on the temperature. Substantial temperature dependence exhibits the coercivity, which decreases from 0.27 T for 4 K down to 0.06 T for 300 K. The material does not exhibit superparamagnetic behaviour.