Optical and magnetic properties of advanced diluted magnetic semiconductor Cd_1-xMn_xIn₂Te₄

A new series of diluted magnetic semiconductor (DMS), Cd_1-xMn_xIn₂Te₄ are successfully synthesized by the vertical bridgman method (VBM). The infrared transmission spectra of Cd_1-xMn_xIn₂Te₄ crystals (x=0.1, 0.22 and 0.4) are measured respectively at room temperature. Magnetic susceptibility measurements on the crystals with different compositions are also carried out in the temperature range of 5 K-300 K using a SQUID magnetometer at H=1T. The value of transmittance is almost a constant in 4000-500 cm^-1 for each crystal, but the energy band gap of Cd_1-xMn_xIn₂Te₄ becomes larger when the composition x increases. The inverse magnetic susceptibilities of Cd_1-xMn_xIn₂Te₄ (x≥0.22) obey Curie-Weiss laws at high temperatures while the curves show down deviation at lower temperatures. Quantitative analysis reveals that the exchange integral constant J₁/k_B is much smaller in Cd_1-xMn_xIn₂Te₄ than that in Cd_1-xMn_xTe for the same concentration of Mn.