We investigated the magneto-optical properties of diluted magnetic semiconductors Cd 1-x Mn x Te crystals grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of x < 0.82. The band-gap energy was depended on Mn mole fraction x linearly and increased with decreasing temperature. The increase of the energy gap with increasing x may be due to a decrease in the lattice constant. Faraday rotation as a function of photon energy with various Mn compositions for CdMnTe in the temperature range of 10-300 K has been measured. The Faraday rotation was increased as the photon energy increased near to that of the fundamental band gap. Verdet constant becomes larger since the effect of the sp-d exchange interaction is enhanced as the temperature is lowered.

We studied the magnetic properties of diluted magnetic semiconductors Cd 0.65-y Mn 0.35 Zn y Te single crystals grown using a vertical Bridgman method. The Cd 0.65-y Mn 0.35 Zn y Te crystals with various Zn mole fractions have been grown in the zinc-blende structure. The band-gap energy obtained from the optical absorption spectrum at 300 K is linearly increased with increasing the addition of Zn into CdMnTe, which may be due to a decrease in the lattice constant. We have observed that the Cd 0.22 Mn 0.35 Zn 0.43 Te crystal showed weak ferromagnetic ordering up to 300 K, and the coercive field was 25 Oe at 250 K. The magnetic moment showed a maximum for the sample with y = 0.43, and the value was approximately ten times larger than that of the Cd 0.65 Mn 0.35 Te crystal. This result reflects that Zn ion mediates and enhances the spin-spin interaction between Mn 2+ ions with increasing Zn composition up to y = 0.43.