Structural and magnetic properties of the new R 2Li 2Si 3 compounds (R = La, Ce, Pr, Nd, Sm)

Abstract

The R 2Li 2Si 3 compounds, with R = La, Ce, Pr, Nd and Sm, synthesized and structurally studied by powder and single crystal X-ray diffraction, belong to the Ce 2Li 2Ge 3 orthorhombic type. The magnetization and heat capacity data show the occurrence of normally trivalent cerium ions in Ce 2Li 2Si 3 ordering ferromagnetically at 17 K. Pr 2Li 2Si 3 becomes antiferromagnetic at 18 K, its isothermal magnetisation at 1.8 K showing a field induced spin flip transition at 25 kOe. For Nd 2Li 2Si 3 the transition to the antiferromagnetic state occurs at 9.5 K. Two peaks are seen in the heat capacity data of Ce 2Li 2Si 3 and Nd 2Li 2Si 3 which can be attributed to either two symmetry inequivalent rare earth sublattices ordering at different temperatures or to spin re-orientation.