COHERENT SPIN TRANSIENT OF EXCITON IN CDTE CD0.6MN0.4TE QUANTUM-WELLS/

We have investigated the coherent exciton in the diluted magnetic semi conductor quantum wells by means of the degenerate-four-wave-mixing (D FWM) with 200 fs time resolution under magnetic field up to 5 T. We ob served the magnetically tunable teraherz oscillation in the time evolu tion of the DFWM signal. We attributed the oscillation to the spin bea t between Zeeman split exciton states, which are excited coherently. T he oscillation period becomes shorter with decreasing the exciton dens ity. This confirm that strong interaction between exciton and the magn etic ion. Further, we found that the spin of the magnetic ion scatters the exciton coherence at zero filed and this effect is suppressed wit h magnetic field.