Abstract-Damping modulated terahertz emission of ferromagnetic films excited by ultrafast laser pulses

 

http://apl.aip.org/resource/1/applab/v101/i7/p072401_s1?isAuthorized=no

Jian Shen^1,2, Xin Fan², Zhiyuan Chen², Matthew F. DeCamp², Huaiwu Zhang¹, and John Q. Xiao²

¹State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China 
²Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA 

Ultrafast demagnetization processes in ferromagnetic films have been shown to produce terahertz (THz) emission. We present an experimental demonstration that, following ultrafast optical excitation, the magnitude of terahertz electromagnetic pulses emitted from a ferromagnetic film is proportional to the Gilbert damping constant, which is conventionally used to describe the damping of magnetization precession. The damping of a ferromagnetic thin film is tuned by using an adjacent nonmagnetic layer, which does not change the magnetization and anisotropy of the ferromagnetic film, allowing an unambiguous determination of the relationship between the THz emission and the damping constant.

© 2012 American Institute of Physics