Lattice parameter values and phase transitions for the Cu2Cd1−zMnzSnSe4 and Cu2Cd1−zFezSnSe4 alloys

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu2Cd1−zMnzSnSe4 and Cu2Cd1−zFezSnSe4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu2Cd0.8Fe0.2SnSe4 as well as for Cu2Cd0.2Fe0.8SnSe4 the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter σ decreases as Cd is replaced by either Mn and/or Fe. For the Cu2Cd1−zMnzSnSe4 and Cu2Cd1−zFezSnSe4 alloy systems, only two single solid phase fields, the tetragonal stannite α  (I4¯2m) and the wurtz–stannite δ (Pmn21) structures were found to occur in the diagram. In addition to the tetragonal stannite α phase extra X-ray diffraction lines due to MnSe and/or FeSe2 were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.