The dynamic response of magnetically ordered materials to an ultrashort external stimulus depends on microscopic parameters, such as magnetic moment, exchange, and spin–orbit interactions. Whereas it is well established that, in multicomponent magnetic alloys and compounds, the speed of demagnetization and spin switching processes has an element-specific character, the magnetization damping was assumed to be a universal parameter for all constituent magnetic elements irrespective of their different spin–orbit couplings and electronic structure. Herein, experimental and theoretical evidence for an element-specific magnetic damping parameter is provided by investigating the ultrafast magnetization response of a high-anisotropy ferrimagnetic DyCo₅ alloy to femtosecond laser excitation. Strikingly different demagnetization and remagnetization dynamics of Dy and Co magnetic moments is revealed by employing femtosecond laser pump–X-ray magnetic circular dichroism probe measurements combined with atomistic spin dynamics (ASD) simulations using ab initio calculated parameters. These observations, fully corroborated by the ASD simulations, are linked to the element-specific spin–orbit coupling strengths of Dy and Co, which are incorporated in the phenomenological magnetization damping parameters. These findings can be used as a recipe for tuning the speed and magnitude of laser-driven magnetic processes and consequently allow control over various dynamic functionalities in multicomponent magnetic materials.

中文翻译：

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元特定磁化阻尼在通过超快X-射线测量显示亚铁DyCo5合金

磁性有序材料对超短外部刺激的动态响应取决于微观参数，例如磁矩、交换和自旋轨道相互作用。而它公认的是，在多组分磁性合金和化合物，退磁和旋转开关过程的速度具有元件特定字符，磁化阻尼被假定为对于全部构成磁性元件，而不论其不同自旋通用参数轨道接头和电子结构。在此，实验和理论的证据的特定元素磁性阻尼参数由调查一的超快响应磁化高各向异性铁氧体磁性DyCo提供₅合金至飞秒激光激发。的Dy和Co磁矩的显着不同的退磁和再磁化动力学是通过使用飞秒激光泵透视磁圆二色性探针测量使用从头计算的参数原子论自旋动力学（ASD）的模拟组合显露。这些观察结果，由ASD模拟充分证实，被链接到Dy和Co的元素特有的自旋轨道耦合强度，这是在该现象磁化阻尼参数并入。这些发现可用作调整激光驱动磁性过程的速度和幅度的方法，从而允许控制多组分磁性材料中的各种动态功能。