Transcript 幻灯片 1 - University of Alabama

Numerical Study of Magnetic Dynamics in Nanoscale Magnets
Yunpeng Wang and X. F. Han
Group M02, State Key Laboratory of Magnetism
Institute of Physics, CAS
Abstract Damping is an important concept in magnetic dynamics, especially in spinpolarized current induced magnetization switching. Generalized LLG equation takes
conduction electron effect into accout and is used to numerically simulate the dynamics in
nanoscale magnets.
[1]
equation includes
The generalized LLG
contribution from conducting electrons and
the damping is anisotropic and non-local.
t m  - m  eff
 
ˆ
D

  0  
ˆ
 m  ( D  t m)
  m   m   m   m 
i x, y , z
t
t
Up Left Figure: Threshold velocity of
magnetic vortex core switching in nanodots
simulated by generalized LLG equation is
consistent with that by original LLG
[4]
equation .
Down Left Figure: Velocity of transverse
domain wall traveling in nanostrips
dependent on magnetic field, no
systemically difference between original
and generalized LLG equation is confirmed.
Conclusion
In the above two studied systems, the
damping contributed by conduction
electrons is not proved to play
determinant role. More systems are
under investigation.
This project was supported by NSFC, MOST, and CAS
[1] Shufeng Zhang, et. al., Phys. Rev. Lett. 102 (2009) 086601
[2] Y. Tserkovnyak, et. al., Phys. Rev. Lett. 88 (2002) 117601
[3] K. Yu, et. al., Phys. Rev. Lett. 100 (2008) 027203
http://www.m02group.com