Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany.
1] Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany [2] Wilhelm Ostwald Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, 04103 Leipzig, Germany.
Nat Commun. 2015 Jan 27;6:6126. doi: 10.1038/ncomms7126.
The main idea behind magnonics is to use the elementary magnetic excitations (magnons) for information transfer and processing. One of the main challenges, hindering the application of ultrafast terahertz magnons in magnonics, has been the short lifetime of these excitations in metallic ferromagnets. Here, we demonstrate that the engineering of the electronic structure of a ferromagnetic metal, by reducing its dimensionality and changing its chemical composition, opens a possibility to strongly suppress the relaxation channels of terahertz magnons and thereby enhance the magnons' lifetime. For the first time, we report on the long-lived terahertz magnons excited in ultrathin metallic alloy films. On the basis of the first-principles calculations, we explain the microscopic nature of the long lifetime being a consequence of the peculiar electronic hybridizations of the species. We further demonstrate a way of tailoring magnon energies (frequencies) by varying the chemical composition of the film.
磁振子学的主要思想是利用基本的磁激发（磁振子）进行信息传递和处理。超快太赫兹磁振子在磁振子学中的应用所面临的主要挑战之一是金属铁磁体中这些激发的短寿命。在这里，我们证明通过降低铁磁金属的维度和改变其化学成分来对其电子结构进行工程设计，为强烈抑制太赫兹磁振子的弛豫通道并从而提高磁振子的寿命开辟了可能性。我们首次报告了在超薄金属合金薄膜中激发的长寿命太赫兹磁振子。基于第一性原理计算，我们解释了长寿命的微观本质是由于物种的特殊电子杂化所致。我们进一步展示了通过改变薄膜的化学成分来调整磁振子能量（频率）的方法。
