Time-resolved Kerr rotation experiments show that two kinds of spin modes exist in diluted magnetic semiconductors: (i) coupled electron-magnetic ion spin excitations and (ii) excitations of magnetic ion spin subsystem, which are decoupled from electron spins. The latter modes exhibit much longer spin coherence time and require a description, which goes beyond the mean field approximation.
@article{arxiv.0801.4756,
title = {Two kinds of spin precession modes in diluted magnetic semiconductors},
author = {M. Vladimirova and S. Cronenberger and P. Barate and D. Scalbert and F. J. Teran and A. P. Dmitriev},
journal= {arXiv preprint arXiv:0801.4756},
year = {2008}
}