Crystal growth of ternary metal sulfides from an open melt: Ba₂MnS₃

We present the growth and characterization of sizable single crystals of the transition metal sulfide Ba₂MnS₃ by the floating-zone technique. Notably, to the best of our knowledge, this method marks the first instance of sulfide melt growth in an open atmosphere, prompting us to detail modifications to our halogen image furnace to eliminate oxygen from the growth atmosphere. This advance is expected to prove valuable for cultivating substantial crystals of other sulfide materials. We present a detailed study of Ba₂MnS₃. Through single crystal X-ray and neutron diffraction, we confirm Ba₂MnS₃ adopts the orthorhombic space group Pnma with unit cell parameters of a = 8.88960 (10) Å, b = 4.33630 (10) Å, c = 17.2210 (2) Å, and V = 663.835 (19) ų at 300 K. By means of magnetometry and specific heat capacity, we identify an antiferromagnetic ground state, with two transitions at 19.6 and 21.1 K. Finally, we elucidate the magnetic ground state through single crystal neutron diffraction, demonstrating the system is described by the magnetic propagation vector k = (0, 1/2, 0) and belongs to the P_b2₁/n magnetic space group.