A study of SmMn2−xCoxGe2 (0≤x≤0.4) intermetallics by magnetic measurements

The magnetic properties of SmMn 2− x Co x Ge 2 (0 ≤ x ≤ 0.4) were studied by field-cooled and zero-field-cooled (ZFC) magnetization measurements in the temperature range 5 K ≤ T ≤ 350 K in low external field (50 Oe). Substitution of Co for Mn leads to a linear decrease in the lattice constants a and c , c / a and the unit cell volume V . Co substitution strongly changed the magnetic properties and the magnetic interactions in the Mn sublattice cross over from a ferromagnetic character to an antiferromagnetic one. The results of earlier neutron diffraction, Mossbauer spectroscopy and specific heat measurements on SmMn 2 Ge 2 are also used for interpreting the magnetization data and to give an account of the competing effects between various magnetic structures in the Mn and Sm sublattices.