Magnetic phase transitions in the CeMn2−xFexGe2 compounds

The crystal structure and magnetic properties of CeMn2−xFexGe2 (0≤x≤1.0) were studied by X-ray powder diffraction and DC magnetization measurements. All the compounds crystallize in ThCr2Si2-type structure. Substitution of Fe for Mn led to a decrease in the unit cell parameters and the unit-cell volume, whereas c/a exhibits parabolic variations. For the samples with x=0.625 and 0.65, the SmMn2Ge2-like magnetic behavior was observed. The results of earlier neutron and Mössbauer studies in CeMn2Ge2 were also used for interpreting the magnetization data and to give an account of the competing effects between various magnetic structures in the Mn sublattice. The results are summarized in a preliminary magnetic phase diagram.