DYNAMIC BEHAVIOUR OF SMALL γFe2O3 CRYSTALLITES. COMPARISON WITH SPIN GLASSES R. Bendaoud, A. R. Fert, J. L. Tholence, J. Souletie and A. Rousset J. Phys. Colloques, 49 C8 (1988) C8-1037-C8-1038 DOI: 10.1051/jphyscol:19888473