论文标题
单秒飞秒脉冲超快磁化切换的通用标准
Universal criteria for single femtosecond pulse ultrafast magnetization switching in ferrimagnets
论文作者
论文摘要
单脉冲切换已在Ferrimagnetic GDFECO和MN $ _2 $ RU $ _X $ GA合金中实验证明。由于缺乏已建立的理论，该理论准确地描述了飞秒激光照相诱导的非平衡反转路径的过渡，因此缺少对单脉冲切换的完全理解。在这项工作中，我们提出了巨磁材料磁化动力学的一般宏观理论。我们的理论在实验中观察到的开关过程的所有阶段都在定量上再现。我们将理论与使用原子旋转动力学方法的计算机模拟进行了直接比较。我们根据微观参数提供了磁化松弛率的明确表达式，这使我们能够提出用于在铁磁铁中切换的通用标准。
Single-pulse switching has been experimentally demonstrated in ferrimagnetic GdFeCo and Mn$_2$Ru$_x$Ga alloys. Complete understanding of single-pulse switching is missing due to the lack of an established theory accurately describing the transition to the non-equilibrium reversal path induced by femtosecond laser photo-excitation. In this work we present general macroscopic theory for the magnetization dynamics of ferrimagnetic materials upon femtosecond laser excitation. Our theory reproduces quantitatively all stages of the switching process observed in experiments. We directly compare our theory to computer simulations using atomistic spin dynamics methods for both GdFeCo and Mn$_2$Ru$_x$Ga alloys. We provide explicit expressions for the magnetization relaxation rates in terms of microscopic parameters which allows us to propose universal criteria for switching in ferrimagnets.
