P02 フェライトナノ粒子のソノケミカル合成とそれらの磁気的性質

抄録

Ferrite nanoparticles, such as magnetite (Fe₃O₄), cobalt ferrite (CoFe₂O₄), manganese zinc ferrite (Mn_xZn_1-xFe₂O₄), etc., were sonochemically synthesized and their magnetic properties were investigated. For magnetite nanoparticles, XRD analyses and TEM observations showed that the synthesized particles were magnetite with ca. 20 nm in diameter. The magnetic susceptibility measurements showed that the magnetite nanoparticles have superparamagnetism with the blocking temperature of 210 K but the remnant magnetization was not zero at 300 K. This is probably because there are some relatively large nanoparticles. For cobalt ferrite nanoparticles, the coercivity was larger than that of magnetite nanoparticles to achieve the desired magnetic characteristics. The morphology, the size and the dispersion of the nanoparticles depended significantly on experimental conditions, while it means they can be controllable by the setting.