CoFeB/MgO铁磁薄膜超快自旋动力学的微区测量  

Spatially Resolved Ultrafast Spin Dynamics in CoFeB/MgO Ferromagnet

作　　者：李艳旭 张桐耀 郭志超 何为[3] 陈院森 张靖[1,2] LI Yanxu;ZHANG Tongyao;GUO Zhichao;HE Wei;CHEN Yuansen;ZHANG Jing(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University,Taiyuan 0300061 China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;State Key Laboratory of Magnetism,Institute of Physics,Chinese Academy of Science,Beijing 100190,China;Attocube Systems AG,Eglfinger Weg2,D-85540 Haar bei Miinchen,Germany})

机构地区：[1]山西大学光电研究所量子光学与光量子器件国家重点实验室,山西太原030006 [2]极端光学协同创新中心,山西太原030006 [3]中国科学院物理研究所磁学国家重点实验室,北京100190 [4]Attocube Systems AG,Eglfinger Weg2,D-85540 Haar bei München,Germany

出　　处：《山西大学学报（自然科学版）》2019年第3期554-561,共8页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(61574087);山西高等学校优秀创新团队(1331KSC)

摘　　要：建立了磁光法拉第效应超快泵浦探测平台,用于高空间分辨率条件下铁磁体系的超快自旋动力学研究。该平台具有亚皮秒量级的时间分辨率,2.0μm的空间分辨率,并且可以任意改变样品表面与磁场的角度。利用该平台对具有各向异性的CoFeB/MgO铁磁薄膜进行了超快自旋动力学研究。激发能量密度的依赖关系表明,超快退磁程度和阻尼因子随着激发能量密度的增加而增大,符合激光带来的热效应,且阻尼因子在低激发密度下可达0.023。实验所得磁化进动频率和反转寿命的外磁场强度依赖关系与基于Landau-Lifshitz-Gilbert方程的理论计算结果吻合。We established spatially and time-resolved Faraday rotation technique of a pump-probe scheme,which used to study ultrafast spin dynamics in ferromagnets.The temporal and spatial resolution is respectively determined 1.0 ps and 2.0μm,and the angle between the sample plane and the magnetic field can be arbitrarily controlled.The ultrafast spin dynamics in a CoFeB/MgO film of magnetism anisotropy is experimentally investigated.The dependence of pump fluence indicates that the demagnetization and the damping factor increase with the increasing pump fluence,which is consistent with the heating effect induced by the pump laser excitation,and the damping factor reach to 0.023 at low excitation density.The magnetization dynamics measured agree well with calculations from the Landau-Lifshitz-Gilbert equation.

关 键 词：法拉第效应 双色泵浦探测 超快自旋动力学 CoFeB/MgO薄膜 

分 类 号：O436.4[机械工程—光学工程]