Morphological and magnetic characteristics of monodispersed Co-cluster assemblies
Morphological and magnetic characteristics of monodispersed Co-cluster assemblies
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DOI：
10.1063/1.371585
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发表时间：
1999-11
影响因子：
3.2
通讯作者：
S. Yamamuro;K. Sumiyama;T. Kamiyama;K. Suzuki
中科院分区：
文献类型：
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作者：
S. Yamamuro;K. Sumiyama;T. Kamiyama;K. Suzuki
使用尺寸可控的簇束沉积系统制备了共簇组装薄膜，通过该系统可以获得平均直径 d=6–13 nm 的单分散钴簇。通过扫描电子显微镜 (SEM)、小角 X 射线散射 (SAXS) 和磁化测量研究了它们的形态和磁性。 SEM 图像显示，薄膜具有由细晶粒组成的多孔结构，没有柱状结构，其密度约为 Co 块体的 25%。SAXS 测量表明，仅在 d=13 nm 时，入射团簇的单分散性通过其组装过程得以保持。所有样品在室温下都表现出铁磁行为，并且矫顽磁场 Hc 随着温度的降低而迅速增加：5 K 时 Hc=168 kA/m (2.1 kOe)。 Hc 的这种增强归因于覆盖 Co 团簇的反铁磁 Co 氧化物层产生的交换各向异性，以及单畴铁的组装。
Co-cluster-assembled films have been prepared using a size-controllable cluster beam deposition system, by which monodispersed Co clusters with a mean diameter, d=6–13 nm are available. Their morphology and magnetic properties have been studied by scanning electron microscopy (SEM), small-angle x-ray scattering (SAXS) and magnetization measurements. The SEM images show that the film has a porous structure consisting of fine grains without a columnar texture and its density is about 25% of the bulk Co. The SAXS measurements indicate that monodispersivity of the incident clusters is maintained through their assembling process only for d=13 nm. All the specimens exhibit ferromagnetic behavior at room temperature and the magnetic coercive field Hc rapidly increases with decreasing temperature: Hc=168 kA/m (2.1 kOe) at 5 K. Such an enhancement in Hc is ascribed to the exchange anisotropy which arises from the antiferromagnetic Co–oxide layers covering the Co clusters, and to the assemblies of single-domain fer...