MAGNETIC VISKOSITY OF UNIFORM GAMMA-FE2O3 PARTICLES WITH DIFFERENT DEGREES OF CATIONIC ORDERING

Results are presented about the time dependence of the magnetization in gamma-Fe2O3 particles obtained from alpha-Fe2O3 through a reduction-oxidation process. The precursor particles were prepared by homogeneous hydrolysis in solution. This preparation method led to a narrow distribution of particle dimensions which allowed us to consider the particles as being monodisperse. The viscosity study included the evaluation of the activation volume of pressed powder samples formed by spindle-like gamma-Fe2O3 particles (aspect ratio 6) with different degree of order in their cationic distribution, at temperatures from 100 to 400 K.