Magnetic Properties of Nanostructured Materials
Magnetic Properties of Nanostructured Materials
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DOI：
10.1007/1-4020-2965-9_23
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
O. Crisan;J. Greneche;Y. Labaye;L. Berger;A. Crisan;M. Angelakeris;J. Lebreton;N. Flevaris
中科院分区：
文献类型：
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作者：
O. Crisan;J. Greneche;Y. Labaye;L. Berger;A. Crisan;M. Angelakeris;J. Lebreton;N. Flevaris
采用实验和数值方法研究了finemet型纳米晶合金和孤立铁磁AgCo纳米颗粒的磁性能。考虑了模拟理想纳米晶合金和孤立纳米粒子的自旋理论模型，并通过低温自旋有序的蒙特卡罗模拟推导了它们的磁性能。在纳米晶合金的情况下，研究了一些有趣的特征，如由纳米颗粒产生的穿透场引起的基体的磁极化，以及晶体部分在整体磁性行为中所起的作用。对于孤立的纳米粒子，表明表面和体各向异性之间的竞争导致表面自旋无序，加上有限尺寸效应，是实验观察到的高外加磁场磁化不饱和的原因。这些模拟结果得到了FINEMET纳米晶合金和孤立铁磁AgCo胶体纳米颗粒的实验数据的证实。
The magnetic properties of FINEMET-type nanocrystalline alloys and isolated ferromagnetic AgCo nanoparticles are investigated both experimentally and numerically. Theoretical models of spins that simulate ideal nanocrystalline alloys and isolated nanoparticles are considered while their magnetic properties are derived from Monte Carlo simulation of low-temperature spin ordering. Interesting features such as magnetic polarization of the matrix due to penetrating fields arising from nanograins and the role played by the crystalline fraction in the overall magnetic behaviour, in the case of nanocrystalline alloys are investigated. For isolated nanoparticles it is shown that the competition between surface and bulk anisotropy gives rise to surface spin disorder that, together with finite-size effects, is responsible for the experimentally observed lack of saturation of the magnetization in high applied fields. These simulation results are confirmed by experimental data obtained on FINEMET nanocrystalline alloys and isolated ferromagnetic AgCo colloidal nanoparticles.