Optical Pump-Probe Detection of Manganese Hyperfine Beats in (Cd,Mn)Te Crystals
Résumé
Optical pump-probe experiments reveal spin beats of manganese ions in (Cd,Mn)Te, due to hyperfine and crystal fields. At "magic" orientations of the magnetic field, the effect of local crystal field is strongly suppressed. In this case, the spin precession of Mn2+ embedded in the lattice approaches the precession expected for the free ion. Following optical excitation, regular spin pulses show up, revealing the one-to-one correspondence between precession frequency and Mn2+ nuclear spin state. The period of the spin pulses accurately determines the hyperfine constant |A|=705 neV. The manganese spin coherence time up to T2Mn≃15 ns is measured for a manganese concentration x=0.0011.