SEMINAR   

　　Synthetic Crystal Research Center, Shanghai Institute of Ceramics   

　　Key Laboratory of Transparent Opto-functional Inorganic Materials, CAS   

　　人工晶体研究中心、中国科学院透明光功能无机材料重点实验室     

　　Femtosecond Laser-Induced Spin Dynamics in Magnetic Materials 

　　Dr. Jing Wu 

　　Physics Department, University of York, York, UK 

　　报告时间：2018年4月23日（周一）上午10:00~11:00 

　　报告地点：长宁园区4号楼3楼会议室  

　　联系人：武安华（021-52414242）  

　　In current semiconductor technology, the operating frequency of transistors is fundamentally limited by the use of electrons and their limited drift velocity. Employing electron spins as an additional degree of freedom and making use of femtosecond optical manipulation of these spins opens up exciting new opportunities. The optical manipulation of spins with a characteristic timescale in the THz regime could increase the operation frequency by up to three orders of magnitude compared to current transistor technology.  

　　In this talk, I will present our studies of ultrafast spin dynamics in various magnetic materials by means of time-resolved pump-probe MOKE measurements. The effects of the laser fluence and polarization on modification of magnetic ordering will be discussed in functional materials such as CoPt multilayers, TbFeCo, CoFeAl, and Fe3O4. A unique dual-pumping technique will be discussed, which demonstrates a possible way to inscribe information to magnetic materials at a desired time scale and shape ultrafast temporal writing. The experimental evidence of direct correlation between Gilbert damping and the density of states at Fermi level will be presented.