A Raman Study Of Order-Disorder Phenomena In Zn1-xMnxGa2Se4 Compounds

A Raman study of order-disorder phenomena in the diluted magnetic semiconductors Zn1-xMnxGa2Se4 series (0x1) is presented. The end compounds ZnGa2Se4 and MnGa2Se4 crystallize in the betam and I space groups respectively, presenting either partial cation disorder (betam) or total cation order (I). In this work, a relation between the shape of a mode at 180 cm-1 and the degree of cation order has been found. This band can be decomposed in a narrow and a broad component, related with the long range order and local non periodicity respectively. Cation ordering has been seen to increase after a heating treatment up to 600 deg C and further cooling to RT.