论文标题
激光诱导的超快GD GD 4F旋转动力学在CO100-XGDX合金中通过时间分辨XMCD
Laser induced ultrafast Gd 4f spin dynamics in Co100-xGdx alloys by means of time-resolved XMCD
论文作者
论文摘要
我们已经研究了激光诱导的超速4F磁性磁序在铁磁CO100-XGDX合金中，以突出原子间交换耦合的作用。我们已经利用了由helmholtz-zentrum柏林的贝西II同步辐射源在Bessy II同步辐射源上传递的超短X射线脉冲，以执行元素和时间分辨的X射线磁性圆形二氯症。 CO72GD28，CO77GD23和CO79GD21合金。大部分磁矩损耗发生在第一个皮秒（PS）内，而电子分布强烈不均衡。在电子和晶格温度（t> 1 ps）的平衡之后，磁损耗发生在较慢的速率上，依赖于合金组成的速率：增加CO组成的速度会加快GD 4F Sublattice的消极作用。取决于组成的原子交换耦合的强度决定了从GD 4F旋转向晶格的角动量流的效率。我们的结果是在定性协议中与铁磁合金的微观三个温度模型的预测。
We have studied the laser induced ultrafast quenching of Gd 4f magnetic order in ferrimagnetic Co100-xGdx alloys to highlight the role of the inter-atomic exchange coupling. We have taken advantage of the ultrashort soft X-ray pulses deliver by the femtoslicing beamline at the BESSY II synchrotron radiation source at the Helmholtz-Zentrum Berlin to perform element- and time-resolved X-ray Magnetic Circular Dichroism spectroscopy.Our results show that the laser induced quenching of Gd 4f magnetic order occurs on very different time-scales for the Co72Gd28, the Co77Gd23 and the Co79Gd21 alloys. Most of the magnetic moment losses occur within the first picosecond (ps) while the electron distribution is strongly out of equilibrium. After the equilibration of the electrons and lattice temperatures (t > 1 ps), the magnetic losses occur on slower rates that depend on the alloy composition: increasing the Co composition speeds up the demagnetization of Gd 4f sublattice. The strength of the inter-atomic exchange coupling which depends on composition, determines the efficiency of the angular momentum flow from the Gd 4f spin towards the lattice. Our results are in qualitative agreements with the predictions of the microscopic three temperatures model for ferrimagnetic alloys.
