Lattice parameter values and phase transitions for the Cu2Cd1−zMnzGeSe4 and Cu2Cd1−zFezGeSe4 alloys

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu2Cd1−zMnzGeSe4 and Cu2Cd1−zFezGeSe4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. The effect of the annealing temperature and cooling rate to room temperature are discussed. For the Cu2Cd1−zFezGeSe4 system, only two single solid phase fields, the tetragonal stannite α and the wurtz-stannite δ structures were found to occur in the diagram. For the Cu2Cd1−zMnzGeSe4 system, in addition to the tetragonal stannite α and the wurtz-stannite δ phases, MnSe was found to exist in the diagram. The DTA experiments showed that the cooling curves for both systems exhibited effects of undercooling.