摘要翻译：
具有Neel表面各向异性、不同内部结构、表面排列和伸长率的磁性纳米颗粒被描述为多自旋系统。结果表明，从立方晶格中切割出的多自旋纳米粒子的能量可以用包含单轴和立方各向异性的有效单自旋势来表示。结果表明，相应常数的值和符号强烈地依赖于颗粒的表面排列、内部结构和伸长率。与从面心立方晶格切割的粒子相比，从简单立方晶格切割的粒子具有有效立方项的相反符号。此外，在具有较强表面效应的纳米颗粒中还观察到其他显著现象：(i)在细长颗粒中，表面效应可以改变单轴各向异性的符号。(ii)在具有立方核的对称粒子（球形和截断八面体）中，各向异性表面效应可以改变其符号。我们还表明，核各向异性和表面各向异性之间的竞争导致了一个新的能量，该能量同时贡献于二阶和四阶有效各向异性。
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英文标题：
《Effective anisotropies and energy barriers of magnetic nanoparticles
  with Neel surface anisotropy》
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作者：
R. Yanes, O. Chubykalo-Fesenko, H. Kachkachi, D. A. Garanin, R. Evans,
  and R. W. Chantrell
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最新提交年份：
2007
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分类信息：

一级分类：Physics        物理学
二级分类：Statistical Mechanics        统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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一级分类：Physics        物理学
二级分类：Materials Science        材料科学
分类描述：Techniques, synthesis, characterization, structure.  Structural phase transitions, mechanical properties, phonons. Defects, adsorbates, interfaces
技术，合成，表征，结构。结构相变，力学性质，声子。缺陷，吸附质，界面
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英文摘要：
  Magnetic nanoparticles with Neel surface anisotropy, different internal structures, surface arrangements and elongation are modelled as many-spin systems. The results suggest that the energy of many-spin nanoparticles cut from cubic lattices can be represented by an effective one-spin potential containing uniaxial and cubic anisotropies. It is shown that the values and signs of the corresponding constants depend strongly on the particle's surface arrangement, internal structure and elongation. Particles cut from a simple cubic lattice have the opposite sign of the effective cubic term, as compared to particles cut from the face-centered cubic lattice. Furthermore, other remarkable phenomena are observed in nanoparticles with relatively strong surface effects: (i) In elongated particles surface effects can change the sign of the uniaxial anisotropy. (ii) In symmetric particles (spherical and truncated octahedral) with cubic core anisotropy surface effects can change its sign. We also show that the competition between the core and surface anisotropies leads to a new energy that contributes to both the 2nd- and 4th-order effective anisotropies.
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PDF链接：
https://arxiv.org/pdf/705.1689