Crystal Structures and Magnetic Properties of Quaternary Manganese Sulfides, BaLn2MnS5 (Ln=La, Ce, and Pr)

The crystal structures and magnetic properties of quaternary manganese sulfides BaLn2MnS5 (Ln=La, Ce, and Pr) are reported. The quaternary manganese sulfides were synthesized by a solid state reaction and determined to have tetragonal structures with space group I4/mcm by the Rietveld method. Their EPR spectra show that the Mn ions are in the 6S5/2 state. The magnetic susceptibilities and the specific heats were measured from 2 to 300 K. The results of the measurements for BaLa2MnS5, BaCe2MnS5, and BaPr2MnS5 exhibit the antiferro-magnetic orderings for Mn2+ ions at 58.5, 62, and 64.5 K, respectively. For BaCe2MnS5 and BaPr2MnS5, the Ce and Pr ions are in the paramagnetic state down to 2 K. The specific heat for BaCe2MnS5 shows a Schottky anomaly at low temperatures.