Correlation of shape and magnetic anisotropy of supported mass-filtered Fe and FeCo alloy nanoparticles on W(110)
Correlation of shape and magnetic anisotropy of supported mass-filtered Fe and FeCo alloy nanoparticles on W(110)
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DOI：
10.1088/0953-8984/20/44/445005
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发表时间：
2008-11-05
影响因子：
2.7
通讯作者：
Getzlaff, M.
中科院分区：
文献类型：
--
作者：
Kleibert, A.;Bulut, F.;Getzlaff, M.
在软着陆和超高真空条件下，在裸露的W（110）表面上沉积质量过滤的Fe和FeCo纳米颗粒。的结构和化学计量的FeCo合金纳米粒子的确定通过非原位高分辨率透射电子显微镜（HRTEM）和能量色散X射线光谱（EDX）对单个纳米粒子，分别证明了晶体结构。原位扫描隧道显微镜（STM）表明，簇不规则地分布在W（110）表面，没有发生碎裂，步骤不作为优先吸附位点，并产生强有力的证据，部分扁平的颗粒沉积后。利用X射线磁圆二色性（XMCD）研究了经质量过滤的纯Fe纳米颗粒在Fe L-3边的磁各向异性能（MAE）。磁化循环揭示了单轴磁各向异性与磁硬轴垂直于表面。实验确定的MAE相比，计算的形状和界面各向异性的贡献，部分扁平的纳米粒子根据STM观察的FeCo集群。
Mass-filtered Fe and FeCo nanoparticles are deposited under soft-landing and ultra-high vacuum conditions on the bare W(110) surface. The structure and the stoichiometry of FeCo alloy nanoparticles are determined by ex situ high resolution transmission electron microscopy (HRTEM) and energy-dispersive x-ray spectroscopy (EDX) on single nanoparticles, respectively, proving a crystalline structure. In situ scanning tunneling microscopy (STM) shows that the clusters are irregularly distributed on the W(110) surface, that no fragmentation occurs, that steps do not act as preferential adsorption sites, and yields strong evidence for a partial flattening of the particles upon deposition. The magnetic anisotropy energy (MAE) of mass-filtered pure Fe nanoparticles is investigated by means of x-ray magnetic circular dichroism (XMCD) at the iron L-3 edge. The magnetization loops reveal an uniaxial magnetic anisotropy with the magnetic hard axis being perpendicular to the surface. The experimentally determined MAE is compared to calculated shape and interface anisotropy contributions of partially flattened nanoparticles according to the STM observations on the FeCo clusters.