The role of faceting and elongation on the magnetic anisotropy of magnetite Fe3O4 nanocrystals
The role of faceting and elongation on the magnetic anisotropy of magnetite Fe3O4 nanocrystals
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DOI：
10.1038/s41598-020-58976-7
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发表时间：
2019-09
影响因子：
4.6
通讯作者：
R. Moreno;S. Poyser;Daniel Meilak;A. Meo;Sarah Jenkins;V. Lazarov;G. Vallejo-Fernandez;S. Majetich;R. Evans
中科院分区：
文献类型：
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作者：
R. Moreno;S. Poyser;Daniel Meilak;A. Meo;Sarah Jenkins;V. Lazarov;G. Vallejo-Fernandez;S. Majetich;R. Evans
Fe3O4纳米粒子具有生物相容性、结构稳定性和良好的磁性，在磁热疗和治疗诊断等生物医学领域具有广阔的应用前景。然而，由于表面和有限尺寸效应的主导地位，所观察到的颗粒的磁性的纳米级起源是未知的。在这里，我们已经开发了一个原子自旋模型的细长磁铁矿纳米晶体，专门解决的作用，小面和伸长的磁形状各向异性。我们发现，对于小面的粒子简单的分析公式高估的磁形状各向异性和基本的立方各向异性作出了显着的贡献，适度拉长的粒子的能量势垒。我们的研究结果使高结晶磁铁矿纳米粒子的有效磁各向异性的更好的估计，是一个步骤，对磁性纳米粒子的加热效应的定量预测。
Fe3O4nanoparticles are one of the most promising candidates for biomedical applications such as magnetic hyperthermia and theranostics due to their bio-compatibility, structural stability and good magnetic properties. However, much is unknown about the nanoscale origins of the observed magnetic properties of particles due to the dominance of surface and finite size effects. Here we have developed an atomistic spin model of elongated magnetite nanocrystals to specifically address the role of faceting and elongation on the magnetic shape anisotropy. We find that for faceted particles simple analytical formulae overestimate the magnetic shape anisotropy and that the underlying cubic anisotropy makes a significant contribution to the energy barrier for moderately elongated particles. Our results enable a better estimation of the effective magnetic anisotropy of highly crystalline magnetite nanoparticles and is a step towards quantitative prediction of the heating effects of magnetic nanoparticles.