Coherent Magnetization Precession in GaMnAs induced by Ultrafast Optical Excitation

J. Qi; Y. Xu; N. Tolk; X. Liu; J. K. Furdyna; I. E. Perakis

doi:10.1063/1.2785114

Coherent Magnetization Precession in GaMnAs induced by Ultrafast Optical Excitation

Materials Science 2009-11-13 v2

Authors: J. Qi , Y. Xu , N. Tolk , X. Liu , J. K. Furdyna , I. E. Perakis

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Abstract

We use femtosecond optical pulses to induce, control and monitor magnetization precession in ferromagnetic Ga0.965Mn0.035As. At temperatures below ~40 K we observe coherent oscillations of the local Mn spins, triggered by an ultrafast photoinduced reorientation of the in-plane easy axis. The amplitude saturation of the oscillations above a certain pump intensity indicates that the easy axis remains unchanged above ~TC/2. We find that the observed magnetization precession damping (Gilbert damping) is strongly dependent on pump laser intensity, but largely independent on ambient temperature. We provide a physical interpretation of the observed light-induced collective Mn-spin relaxation and precession.

Keywords

magnetization precession gamnas ultrafast optical excitation gilbert damping ferromagnetic semiconductor spin dynamics easy axis reorientation

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@article{arxiv.0706.4270,
  title  = {Coherent Magnetization Precession in GaMnAs induced by Ultrafast Optical Excitation},
  author = {J. Qi and Y. Xu and N. Tolk and X. Liu and J. K. Furdyna and I. E. Perakis},
  journal= {arXiv preprint arXiv:0706.4270},
  year   = {2009}
}

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7 pages,3 figures

Coherent Magnetization Precession in GaMnAs induced by Ultrafast Optical Excitation

Abstract

Keywords

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