Magnetism of single-crystalline Fe nanostructures.
Magnetism of single-crystalline Fe nanostructures.
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单晶铁纳米结构的磁性。
DOI：
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发表时间：
2010
影响因子：
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通讯作者：
I. Barsukov
中科院分区：
文献类型：
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作者：
J. Lindner;C. Hassel;A. Trunova;F. Römer;S. Stienen;I. Barsukov
通过铁磁共振的磁性纳米结构的定量研究证明了单晶铁纳米结构。结果表明，单晶性质导致的影响不存在于多晶的，并有助于定量解释的结果。首先，提出了一种方法，使人们能够制造外延Fe纳米线从Fe的薄膜在GaAs（110）上生长在真空条件下。由于立方和双重磁各向异性的组合，该系统允许制备其剩磁中的易磁化轴垂直于线轴取向的线。这种独特的功能只能在外延系统中实现。此外，我们还研究了用湿化学方法制备的边长为13.6 nm的近乎完美的Fe纳米立方体。虽然颗粒的壳由Fe_3O_4或γ-Fe_2O_3组成，但核由金属Fe组成。氧和氢等离子体用于去除配体系统和氧化物壳。立方体的单晶性质使人们能够通过对系综的铁磁共振测量以及基于Landau-Lifshitz方程的模型来定量确定单个颗粒的磁性质。测量结果表明，磁晶各向异性K4 = 4.8。10（4）J/m3等于体值，饱和磁化强度降低到M（5 K）=（1.2 +/-0.12）。10（6）A/m（体积值的70%）。的有效阻尼参数α = 0.03增加了一个数量级，相对于散装铁，表明在纳米结构中的磁阻尼不同于散装。
The quantitative investigation of magnetic nanostructures by means of ferromagnetic resonance is demonstrated for single-crystalline iron nanostructures. It is shown that the single-crystalline nature leads to effects not being present in polycrystalline ones and helps to quantitatively interpret the results. First a method is presented that enables one to fabricate epitaxial Fe nanowires starting from a thin film of Fe grown under ultrahigh vacuum conditions on GaAs (110). The system allows, due to the combination of cubic and twofold magnetic anisotropy, to prepare wires whose easy axis in remanence is oriented perpendicular to the wires axis. This unique feature is only achievable in epitaxial systems. Furthermore, nearly perfect Fe nanocubes with 13.6 nm edge length prepared by wet-chemical methods are studied. While the shell of the particles is composed of either Fe3O4 or gamma-Fe2O3, the core consists of metallic Fe. Oxygen and hydrogen plasma are used to remove the ligand system and the oxide shell. The single-crystalline nature of the cubes enables one to quantitatively determine the magnetic properties of the individual particle by means of ferromagnetic resonance measurements on an ensemble together with a model based on the Landau-Lifshitz equation. The measurements reveal a magneto-crystalline anisotropy of K4 = 4.8. 10(4) J/m3 being equal to bulk value and a saturation magnetization which is reduced to M(5K) = (1.2 +/- 0.12). 10(6) A/m (70% of bulk value). The effective damping parameter alpha = 0.03 is increased by one order of magnitude with respect to bulk Fe, showing that magnetic damping in nanostructures differs from the bulk.