強磁性微粒子の太い鎖状クラスタ形成に関する3次元モンテカルロ・シミュレーション

抄録

Three-dimensional Monte Carlo simulations have been carried out in order to investigate the thick chainlike cluster formation of ferromagnetic fine particles in an applied magnetic field. The results of the aggregate structures are summarized as follows. If a magnetic field is sufficiently strong and magnetic particle-particle interactions are relatively strong, thick chainlike clusters are formed along a field direction. The thick chainlike clusters obtained by the simulations agree well with those observed experimentally. For the increased particle-particle interactions, high potential barriers arise between thin chainlike clusters, so that it is impossible for the thin chainlike clusters to aggregate to form thick chainlike clusters. In small magnetic fields, thick chainlike clusters are not observed, since looplike clusters are preferred to linear clusters in this situation, whereby strong attractive forces do not act between clusters, due to flux closure.