Structure and magnetic properties of Fe/Fe oxide clusters
Structure and magnetic properties of Fe/Fe oxide clusters
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DOI：
10.1007/s11051-008-9463-3
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发表时间：
2008-01-01
影响因子：
2.5
通讯作者：
Binns, C.
中科院分区：
文献类型：
--
作者：
Crisan, O.;von Haeften, K.;Binns, C.
在超高真空条件下，采用气体稳定的团簇聚集法合成了Fe团簇，并对其进行了自然氧化，得到了Fe/Fe氧化物核壳结构纳米粒子。单个纳米颗粒的形态，如通过透射电子显微镜所揭示的，由平均直径为4.4 nm的Fe核组成，所述Fe核被平均厚度为约1.2 nm的均匀氧化物壳包围。纳米颗粒可以与铁/反铁磁（FM/AF）系统同化。的形态结构特征已与磁测量的核壳纳米粒子。当样品在3 T的外加磁场下场冷时，测量到了显著的交换偏置效应。由于冠状AF层的特定几何形状，核壳纳米团簇的形态比规则厚度的FM/AF双层复杂得多，因此必须考虑形状和表面各向异性以正确解释磁性数据。
Fe clusters have been synthesised in ultrahigh-vacuum chamber using a gas-stabilized cluster aggregation method that ensures good control of the cluster size and naturally oxidized in order to obtain Fe/Fe oxide core-shell nanoparticles. The morphology of an individual nanoparticle, as revealed by transmission electron microscopy, consists of a Fe core of an average diameter of 4.4 nm surrounded by an oxide shell of uniform thickness of about 1.2 nm in average. The nanoparticles may be assimilated with a ferro-/antiferromagnetic (FM/AF) system. The morpho-structural features have been correlated with magnetic measurements on the core-shell nanoparticles. A significant exchange bias effect has been measured, when the sample was field-cooled under an applied field of 3 T. As the morphology of core-shell nanoclusters is much more complicated than in FM/AF bilayers of regular thickness due to the particular geometry of the coronal AF layer, the shape and surface anisotropy have to be taken into account for a correct interpretation of the magnetic data.