Crystal structures and magnetic properties of novel compounds Sc2CoIn and Sc100Co25In7

Crystal structures of two novel scandium-rich ternary compounds forming in the Sc-Co-In system, obtained by arc-melting of pure metals, were determined using X-ray powder diffraction. The structure of Sc2CoIn (space group P4/mmm, а = 3.2887(2), ≿ = 7.1642(4) Å, Z = 1, RI = 5.97%) can be derived from the CsCl-type structure. In turn, the structure of Sc100Co25In7 (space group Fm-3, а = 17.7411(5) Å, Z = 2, RI = 8.08%) is related to the structures of Sc50T13In3 (T = Rh, Ir) and ɛ-Ag7+xMg26-x (x = 0.96). The magnetic properties of both phases were studied at low temperatures down to 1.7 K. The indide Sc2CoIn was found to order antiferromagnetically at 65 K due to the magnetic moments carried on Co atoms. In contrast, Sc100Co25In7 was characterized as a weak Pauli paramagnet.