Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany.
Nat Nanotechnol. 2013 Nov;8(11):853-8. doi: 10.1038/nnano.2013.188. Epub 2013 Sep 22.
The fundamental interactions between magnetic moments at interfaces have an important impact on the properties of layered magnetic structures. Hence, a direct probing of these interactions is highly desirable for understanding a wide range of phenomena in low-dimensional solids. Here we propose a method for probing the magnetic exchange interaction at buried interfaces using spin-polarized electrons and taking advantage of the collective nature of elementary magnetic excitations (magnons). We demonstrate that, for the case of weak coupling at the interface, the low-energy magnon mode is mainly localized at the interface. Because this mode has the longest lifetime of the modes and has a finite spectral weight across the layers on top, it can be probed by electrons. A comparison of experimental data and first-principles calculations leads to the determination of the interface exchange parameters. This method may help the development of spectroscopy of buried magnetic interfaces.
界面处磁矩之间的基本相互作用对层状磁结构的性质有重要影响。因此，直接探测这些相互作用对于理解低维固体中的广泛现象是非常有必要的。在这里，我们提出了一种利用自旋极化电子并利用基本磁激发（磁子）的集体性质来探测埋层界面处磁交换相互作用的方法。我们证明，在界面处弱耦合的情况下，低能磁子模式主要局域在界面处。由于这个模式具有最长的寿命，并且在顶层的层间有有限的谱权重，因此它可以被电子探测到。实验数据和第一性原理计算的比较得出了界面交换参数的确定。这种方法可能有助于埋层磁性界面光谱学的发展。
