Photoinduced precession of magnetization in ferromagnetic (Ga,Mn)As.
Precession of magnetization induced by pulsed optical excitation is observed in a ferromagnetic semiconductor (Ga,Mn)As by time-resolved magneto-optical measurements. It appears as complicated oscillations of a polarization plane of linearly polarized probe pulses, but is reproduced by gyromagnetic theory incorporating an impulsive change in an effective magnetic field due to a change in the magnetic anisotropy. The shape of the impulse suggests a significant nonthermal contribution of photogenerated carriers to the change in anisotropy through spin-orbit interaction.
Hashimoto
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Y
Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259-G2-13 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan. hashimoto.y.ad@m.titech.ac.jp
Kobayashi
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S
Munekata
H
H