Ultrafast photo-induced turning of magnetization and its relaxation dynamics in GaMnAs

We report that, by linearly polarized pumping of different wavelengths, Kerr transients appear at zero magnetic field only in the case when GaMnAs samples are initialized at 3 K by first applying a 0.8 Tesla field and then returning to zero field. We find that, instead of magnetization precession, the near-band gap excitation induces a coherent out-of-plane turning of magnetization, which shows very long relaxation dynamics with no precession. When photon energy increases, the peak value of the Kerr transient increases, but it decays rapidly to the original slow transient seen under the near-band-gap excitation.

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Made available in DSpace on 2010-05-24T07:15:54Z (GMT). No. of bitstreams: 1 Ultrafast photo-induced turning of magnetization and its relaxation dynamics in GaMnAs.pdf: 634007 bytes, checksum: 725308005155f893439c1af4306adf95 (MD5) Previous issue date: 2010

National Basic Research Program of China 2006CB932801 2007CB924903 2007CB924904 Chinese Academy of Sciences KJCX.YW.W09 National Natural Science Foundation of China 60836002 10674130 6052100

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National Basic Research Program of China 2006CB932801 2007CB924903 2007CB924904 Chinese Academy of Sciences KJCX.YW.W09 National Natural Science Foundation of China 60836002 10674130 6052100