The magnetic behaviours of R1−Gd Mn2Si2 (R: Ce and Pr) in weak magnetic field

The structures and magnetic properties of Ce 1− x Gd x Mn 2 Si 2 and Pr 1− x Gd x Mn 2 Si 2 (0.2 ≤ x ≤ 0.8) were studied by X-ray powder diffraction and dc magnetization measurements. All compounds crystallize in the ThCr 2 Si 2 -type structure with space group I4/mmm . Substitution of Ce or Pr for Gd leads to a linear increase in the lattice constants and the unit cell volume. Below the Curie temperature T C Gd , the Gd sublattice orders and reconfigures the ordering of the Mn sublattice in Ce 1− x Gd x Mn 2 Si 2 and Pr 1− x Gd x Mn 2 Si 2 . With increasing concentration of Ce or Pr, T C Gd decreases in both compounds. Below T C Gd in Pr 1− x Gd x Mn 2 Si 2 , we observed a phase transition temperature as in Nd 0.6 Gd 0.4 Mn 2 Si 2 . The results for both systems are summarized in a preliminary magnetic phase diagram.