Physical properties of Ce2CoSn2

A complete physical characterisation, through specific heat, electrical resistivity and magnetization measurements was performed, in a wide temperature range on the new phase Ce2CoSn7, which crystallizes in a very large fee cell with a structure type similar to the Tb117Fe52Ge112 one. From the real part of the AC susceptibility data a broad maximum call be observed at 7 K with an inflexion point, hi agreement with the maximum observed in the imaginary part of the AC susceptibility, at a lower temperature (around 6 K). We hypothesize that the lower maximum can be attributed to an antiferromagnetic transition while the upper one could be related to the onset of a Kondo regime, ale antiferromagnetic order is confirmed by magnetization measurements performed at 2 K in magnetic fields up to 9 Tesla: a metamagnetic transition could be observed around 0.4 Tesla. In the paramagnetic range the inverse of susceptibility follows a modified Curie-Weiss law, with an effective paramagnetic moment mu =2.89 mu (B) and a paramagnetic Curie temperature slightly positive. The heat capacity results suggest that this phase might be a heavy fermion system, with an electronic specific heat coefficient gamma =1.3 J/K-2 mel. The electrical resistivity measurements exhibit a pronounced minimum at about 13 It and below this temperature a logarithmic Kondo-like behaviour is observed. (C) 2001 Elsevier Science B.V. All rights resented.