Nahas Y, Repain V, Chacon C, Girard Y, Lagoute J, Rodary G, Klein J, Rousset S, Bulou H, Goyhenex C
Laboratoire Matériaux et Phénomènes Quantiques, Université Paris-Diderot Paris 7, UMR CNRS 7162, 75205 Paris Cedex 13, France.
Phys Rev Lett. 2009 Aug 7;103(6):067202. doi: 10.1103/PhysRevLett.103.067202. Epub 2009 Aug 6.
Self-organized Co nanodots on a Au(111) surface have been surrounded by controlled Au rings that progressively cap the entire dots. The magnetic susceptibility of these dots has been measured in situ as a function of the Au coverage. The blocking temperature increases when the Co bilayer dots are surrounded by the first Au atomic layer and decreases with the subsequent capping. This result cannot be explained by interfacial anisotropy which is generally assumed to be the dominant term in the magnetic anisotropy of nanostructures. Using molecular dynamics simulations, we evidence that the large strain inside the Co clusters is the main driving force for the anisotropy changes during the Au encapsulation.
在Au(111)表面上自组织形成的Co纳米点已被可控的Au环包围，这些Au环逐渐覆盖整个纳米点。已原位测量了这些纳米点的磁化率随Au覆盖率的变化。当Co双层纳米点被第一层Au原子层包围时，阻塞温度升高，而随着后续的覆盖，阻塞温度降低。这一结果无法用界面各向异性来解释，而界面各向异性通常被认为是纳米结构磁各向异性中的主导项。通过分子动力学模拟，我们证明了Co团簇内部的大应变是Au封装过程中各向异性变化的主要驱动力。
