3-DIMENSIONAL MONTE-CARLO SIMULATIONS OF THICK CHAIN-LIKE CLUSTERS COMPOSED OF FERROMAGNETIC FINE PARTICLES

Three-dimensional Monte Carlo simulations have been carried out in ord er to investigate the thick chainlike fluster formation of ferromagnet ic fine particles in an applied magnetic field, The results of the agg regate structures are summarized as follows. If a magnetic field is su fficiently strong and magnetic particle-particle interactions are rela tively strong, thick chain like clusters are formed along a field dire ction. The thick chain like clusters obtained by the simulations agree well with those observed experimentally, For the increased particle-p article interactions, high potential barriers arise between thin chain like clusters, so that it is impossible for the thin chainlike cluster s to aggregate to form thick chainlike clusters. In small magnetic fie lds, thick chainlike clusters are not observed, since nonlinear cluste rs are preferred to linear clusters in this situation, whereby strong attractive forces do not act between clusters, due to flux closure. (C ) 1996 Academic Press, Inc.