Magneto-optical properties for bulk Cd0.63−yMn0.37HgyTe single crystals

Abstract

We investigated the magneto-optical properties of diluted magnetic semiconductor Cd1-x-yMnxHgyTe (x similar to 0.37) single crystals grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of y <= 0.07. The band gap energy increases with increasing y (<= 0.03), while decreases with increasing y (>= 0.03). An anomalous behavior was also observed in the magnetic susceptibility and electrical resistivity. Faraday rotation as a function of photon energy with various Hg compositions for CdMnHgTe in the temperature range of 10-300 K has been measured. The Verdet dispersion curves were enhanced near the fundamental band gap energy. The Verdet constant becomes larger since the effect of the sp-d exchange interaction is enhanced as the temperature is lowered. At 10 K, the Verdet constants of the Faraday rotation for the samples with y=0, 0.01, 0.03, 0.05, and 0.07 were observed to be -1.09, -2.57, -3.94, -0.97, and -0.87 deg/G cm at 613 nm, respectively. The Verdet constant showed a maximum for the sample with y=0.03, and the value is approximately four times larger than that of the Cd0.63Mn0.37Te crystal. The Verdet constant has a maximum around Hg compositions with y similar to 0.03, and this result agrees well with the behavior of the magnetic susceptibility. This result reflects that Hg ion mediates and enhances the spin-spin interaction between Mn2+ ions with increasing Hg composition up to y similar to 0.03.