We report the phenomenon of size segregation and the experimental evidence for the presence of correlated areas mediated by dipolar interactions in three-dimensional Fe nanoparticle assemblies.Iron nanoparticles dispe...We report the phenomenon of size segregation and the experimental evidence for the presence of correlated areas mediated by dipolar interactions in three-dimensional Fe nanoparticle assemblies.Iron nanoparticles dispersed in ethanol assemble into tabular whiskers (8 μm × 40 μm in cross section with lengths up to 1 0 cm) due to dipolar interactions.Magnetic force microscopy observations on iron nanoparticle compact assemblies prove the local magnetic correlation of the Fe nanoparticles due to dipolar coupling and the formation of domain-like structures in expanded dimensions.Magnetic measurements show that the coercivity and the low field magnetic susceptibility of the Fe nanoparticle assemblies increase while the saturation magnetization decreases with the increasing interparticle distance.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10874159,11074227 and 50801039Zhejiang Natural Science Foundation(R6110362)the Fundamental R&D Program for Core Technology of Materials by the Ministry of Knowledge Economy,R.Korea.
文摘We report the phenomenon of size segregation and the experimental evidence for the presence of correlated areas mediated by dipolar interactions in three-dimensional Fe nanoparticle assemblies.Iron nanoparticles dispersed in ethanol assemble into tabular whiskers (8 μm × 40 μm in cross section with lengths up to 1 0 cm) due to dipolar interactions.Magnetic force microscopy observations on iron nanoparticle compact assemblies prove the local magnetic correlation of the Fe nanoparticles due to dipolar coupling and the formation of domain-like structures in expanded dimensions.Magnetic measurements show that the coercivity and the low field magnetic susceptibility of the Fe nanoparticle assemblies increase while the saturation magnetization decreases with the increasing interparticle distance.
