Surface effects in CoFe2O4 magnetic fluids studied by Mossbauer spectrometry

Magnetic properties of CoFe2O4 particles were investigated by means of zero-field and in-field Mossbauer spectrometry. The studies include superparamagnetic (SP) relaxation as well as the surface phenomena of samples with different particle sizes both in the form of ferrofluids and powders. A core-shell model was applied to estimate the thickness of the surface spin-canted shell around particles. (C) 2002 Elsevier Science B.V. All rights reserved.