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

The La(Mn
1-x
Cr
x
)
2
Ge
2
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 I
s
per Mn atom at 4.2 K and Curie temperature T
c
were determined as functions of Cr substitution x. Both I
s
and T
c
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 E
f
with Cr, Fe, or Co substitution may be possible.