New Diluted Magnetic Semiconductor Mn <sub> The X </ Sub> Of Cd <sub> 1-x </ Sub> The In <sub> 2 </ Sub> Te <sub> 4 </ Sub> Crystal Growth And Organization Structure And Performance Research,

MnxCd1-xIn2Te4 is a new quaternary diluted magnetic semiconductor that possesses special photoelectric and magnetic properties as well as excellent magneto-optical effects,because of its strong sp-d coupling effects. There are only a few reports on MnxCd1-xIn2Te4 crystal. In the present dissertation,the researches on the growth technologies and the physical properties of MnxCd1-xIn2Te4 crystals have been reported. MnxCd1-xIn2Te4 ingots were grown by Bridgman method. The phase formation,phase structure,growth interface morphology and compositional redistribution in MnxCd1-xIn2Te4 ingots were analyzed. Its optical,electrical and magnetic properties and giant Faraday rotation were also examined.Generally speaking,it is difficult to get high quality MnxCd1-xIn2Te4 crystals because of its low thermal conductivity and multi components. According to the thermal parameters of MnxCd1-xIn2Te4,a high temperature gradient furnace was designed in the present work. The slow growth rate of 0.6mm/h and Imm/h were used for reducing the depth of the growth interface. ACRT was introduced in some ingots to homogenize their composition distribution along their radius. Solid state recrystallization method was also tried to get low segregation crystals.The etchant suitable for MnxCd1-xIn2Te4 crystals was found out,with which we got well-etched surfaces. The etched surface of the section cut along the centerline of the ingots shows that,there are three phase-regions in MnxCd1-xIn2Te4 ingots,a with the precipitated B1 and B phase are observed at the tip of MnxCd1-xIn2Te4 ingots. The morphology of the P phase is in the forms of plate,flower or near-round. Among them,3 plates always lies in the grain boundaries. Following the initial region,single P phase region and In2Tes phase region are formed in order. Two concave interfaces in the MnxCd1-xIn2Te4 ingots were found. The one near the tip is the transient interface from a + P phase growth to P phase growth and the other is that from P phase growth to In2Te3 phase growth. Quenched interfaces obtained by shutting off the power during the growth also confirms that the growth interface is a concave one. The defects such as cracks,dislocations and twins in MnxCd1-xIn2Te4 ingots were also detected.The concentration distribution along the longitudinal axis was analyzed. It is shown that Mn and Cd contents decrease while In and Te contents increase with the distance from the beginning of the ingot. Based on the experimental data,the partition ratios of Mn,Cd and In at the growth interface are evaluated to be 1.286,1.926 and 0.729 for a phase growth process,and 1.120,1.055 and 0.985 for P phase growth process respectively. Cd content along the longitudinal axes was calculated using the model for HgTe-MnTe crystals grown by ACRT-B proposed by Jie. The calculation results agree well with the experimental results.The depth of growth interface seriously affects the crystal quality. The experimental results show that the variation range of Cd content in different sections cut along the axes increases with the growth process,which reflects that the interface depth also becomes larger.The lattice structure of P phase is chalcopyrite in the nomenclature of (Mn,Cd)In2Te4,while that of a phase is fee in the nomenclature (Mn,Cd)3hi2Te6. The lattice parameters can be extrapolated according to X-ray spectra. The lattice parameters a,c and c/a of P phase are found to change linearly with x.Optical absorption measurements show that MnxCd1-xIn2Te4 is a direct energy gap semiconductor and the band gap shifts towards the high energy side with the increase of x. The optical transmittance is high in the wave length range from 1 to 25 u m for MnxCd1-xIn2Te4.The electronic properties have been investigated by Hall measurements. It was found that,the as grown crystal of MnxCd1-xIn2Te4 is P type semiconductor,both the charge density and the resistivity increase with x value,while the carrier mobility decreases with x.Magnetization measurements show that MnxCd1-xIn2Te4 is paramagnet and the magnet...