The structure and magnetic properties of Th4Mn13Sn5

We have synthesized the new intermetallic compound Th4Mn13Sn5: it crystallizes with the Th4Fe13Sn5 type structure, tetragonal tP44, space group P4/mbm, a = 8.423(1) Å and c = 11.972(2) Å. The Mn ions in Th4Mn13Sn5 order ferro/ferrimagnetically around 110 K. A low magnetization of 0.13 μB/Mn at 4.2 K in a field of 70 kOe and a large fractional temperature independent contribution to susceptibility in the paramagnetic regime suggest an appreciable itinerancy of the Mn 3-d state in this compound. The electrical resistivity shows an anomaly at the magnetic transition and varies as T2 below 30 K with a coefficient of 8.38 × 10−3 μΩ cm/K2. The low temperature heat capacity data furnish a Sommerfeld coefficient of 16.9 mJ/g atom K2. In the course of present work we have also identified the ThMn0.2Sn2 phase which adopts a defective CeNiSi2 type structure, orthorhombic oS16, space group Cmcm with a = 4.476(2) Å, b = 17.059(3) Å and c = 4.398(1) Å.