We have performed infrared and far-infrared magneto-transmission experiments for Cd1-xFexS (x = 0.05) and Ga1-xMnxAs (x = 0.00004, 0.053) at very high magnetic fields up to 500 T. The cyclotron mass of electrons in Cd1-xFexS (x = 0.05) was found to be larger than that in CdS when we applied magnetic fields parallel to the c-axis of the crystal; the relative increase of the cyclotron mass shows anomalous temperature dependence at 85-300 K. Hole cyclotron resonance was observed in Ga1-xMnxAs (x = 0.00004) at 119 μm and 70.5 μm. In Ga1-xMnxAs (x = 0.053) far-infrared transmission does not show any resonance but a rapid decrease of transmission with magnetic field; the magneto-transmission spectrum depends strongly on temperature.
- Cyclotron resonance
- Diluted magnetic semiconductor
- Infrared magneto-transmission
- Megagauss magnetic fields