Ultrafast optical modulation of exchange coupling in FePt∕CoFe composite structure
Ultrafast optical modulation of exchange coupling in FePt∕CoFe composite structure
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DOI：
10.1063/1.2916704
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发表时间：
2008-04
影响因子：
4
通讯作者：
Yang Ren;Hui Zhao;Zongzhi Zhang;Q. Jin
中科院分区：
文献类型：
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作者：
Yang Ren;Hui Zhao;Zongzhi Zhang;Q. Jin
用光泵浦光探测方法研究了FePt/CoFe双层膜的光致磁化动力学。由于光激发引起的FePt层和CoFe层之间的交换去耦合，瞬时Kerr环表现出瞬时分离的开关行为，然后在10-20ps的一定延迟时间恢复到原来的均匀开关。通过分析FePt/CoFe的磁化强度比和FePt相的矫顽力随时间的变化关系，我们推断，退耦合和慢磁化恢复现象主要归因于激光在FePt层中产生的自旋无序，其次是界面耦合的发生是自旋/晶格冷却过程的结果。
Photoinduced magnetization dynamics in FePt∕CoFe bilayer is investigated by optical pump-probe measurements. The transient Kerr loops exhibit an instantaneous separated switching behavior due to exchange decoupling between FePt and CoFe layers induced by photoexcitation, which subsequently recover to the original uniform switching at a certain delay time of 10–20ps. By analyzing the temporal dependence of magnetization ratio of FePt to CoFe and coercivity of FePt phase, we infer that the decoupling and slow magnetization recovery phenomena are ascribed to the laser-created spin disordering mainly in FePt layer, while the following onset of interfacial coupling results from spin/lattice cooling process.