Growth behavior and crystal structures of different phases in Mn_xCd_1-xIn₂Te₄ grown by Bridgman method

Three ingots of diluted magnetic semiconductor Mn_xCd_1-xIn₂Te₄ with x = 0.1, 0.22 and 0.4, respectively, were grown by Bridgman method. The structure of the phases detected in the ingots and the composition distribution were analyzed. α and β₁ phases are formed in the initial region of the ingots, where α phase is supposed to be crystallized from the melt while β₁ is precipitated from α phase in the solid state. Then, β phase appears around α grain boundaries, and the content of β phase increases with the evolution of the growth process until a single β phase region forms. The structure of α phase is determined to be cubic while that of β phase is a chalcopyrite. In the final region of the ingots, In₂Te₃ phase with FCC structure is crystallized. Two distinct interfaces between the different neighboring phase regions are observed on the longitudinal section. It is also found that Mn and Cd contents decrease while In and Te contents increase with the distance from the ingot tip.