Hydrolysis and pyrosol methods have been used to synthesize beta-and g
amma-FeOOH. Different temperatures were used in order to transform the
se precursors to gamma-Fe2O3 and therefore different size distribution
and surface/volume ratio were observed. Consequently, distinct magnet
ic behaviour (superparamagnetic or ferrimagnetic) in gamma-Fe2O3 depen
ding on the precursor obtention method was observed.