Magnetic Properties of Layer Structure Compound La (CrxMn1-x)2Ge2

The La(Mn1-xCrx)2Ge2 system (with a Mn-Ge-La-Ge-Mn layer structure) was studied in order to clarify the effect of the manganese 3d electrons, and to find properties with potential applications. Homogeneous single-phase samples were prepared, and the saturation magnetic moment Is per Mn atom at 4.2 K and Curie temperature Tc were determined as functions of Cr substitution x. Both Is and Tc decreased monotonically with x, and the system turns paramagnetic for x ≫ 0.5; similar results were obtained for Fe- and Co-substitution. An explanation in terms of a sharp decrease in the density of states of 3d electrons at Ef with Cr, Fe, or Co substitution may be possible.