Manipulating magnetic anisotropy and ultrafast spin dynamics of magnetic nanostructures
Manipulating magnetic anisotropy and ultrafast spin dynamics of magnetic nanostructures
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DOI：
10.1088/1674-1056/24/7/077505
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发表时间：
2015-05
影响因子：
1.7
通讯作者：
Zhaohua Cheng;Wei He;Xiang-qun Zhang;D. Sun;H. Du;Qiong Wu;Jun Ye;Ya-Peng Fang;Haoliang Liu-Haolia
中科院分区：
文献类型：
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作者：
Zhaohua Cheng;Wei He;Xiang-qun Zhang;D. Sun;H. Du;Qiong Wu;Jun Ye;Ya-Peng Fang;Haoliang Liu-Haolia
我们提出了我们广泛的研究磁各向异性。我们采用一种新颖的方法来调节Si（111）衬底的台阶宽度：改变加热电流的方向，从而通过修饰台阶上的原子台阶来控制台阶上磁性结构的磁各向异性。利用时间分辨磁光克尔效应（TR-MOKE）研究了CoFeB/MgO/CoFeB磁性隧道结中两层磁性层间平行态（P态）和反平行态（AP态）磁化的激光诱导超快退磁.观察到AP态比P态的退磁时间短，退磁幅度大。这些行为归因于两个CoFeB层之间的超快自旋转移，通过隧穿热电子通过MgO势垒。我们的观察表明，超快退磁可以工程的热电子隧穿电流。这为操纵磁隧道结中的超快自旋电流打开了大门。此外，全光学TR-MOKE技术为探索铁磁材料，特别是金属材料中的非线性磁化动力学提供了灵活性。
We present our extensive research into magnetic anisotropy. We tuned the terrace width of Si(111) substrate by a novel method: varying the direction of heating current and consequently manipulating the magnetic anisotropy of magnetic structures on the stepped substrate by decorating its atomic steps. Laser-induced ultrafast demagnetization of a CoFeB/MgO/CoFeB magnetic tunneling junction was explored by the time-resolved magneto-optical Kerr effect (TR-MOKE) for both the parallel state (P state) and the antiparallel state (AP state) of the magnetizations between two magnetic layers. It was observed that the demagnetization time is shorter and the magnitude of demagnetization is larger in the AP state than those in the P state. These behaviors are attributed to the ultrafast spin transfer between two CoFeB layers via the tunneling of hot electrons through the MgO barrier. Our observation indicates that ultrafast demagnetization can be engineered by the hot electron tunneling current. This opens the door to manipulate the ultrafast spin current in magnetic tunneling junctions. Furthermore, an all-optical TR-MOKE technique provides the flexibility for exploring the nonlinear magnetization dynamics in ferromagnetic materials, especially with metallic materials.