Department of Physics, University of York, York YO10 5DD, U.K.
Sci Rep. 2013 Nov 20;3:3262. doi: 10.1038/srep03262.
There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime.
最近，人们对利用飞秒激光激发发现的热诱导磁化反转产生了浓厚的兴趣，在无需外加磁场的情况下，铁磁系统可以确定性地进行反转。实验结果表明，反转是由于材料的固有特性引起的，但到目前为止，导致反转的微观机制尚未确定。我们使用计算和分析方法表明，这种转变是由双磁子束缚态的激发引起的，其性质取决于材料因素。这一发现使我们能够准确预测反转的开始，并且确定这一机制将允许为太赫兹范围内的存储设备识别或设计新的材料。
