Abstract and subjects
We report specific heat (C) and magnetization (M) of single crystalline Ce4Pt12Sn25 at temperature down to approximate to 50 mK and in fields up to 3 T. C/T exhibits a sharp anomaly at 180 mK, with a large jump in a Sommerfeld coefficient gamma = C/T of Delta gamma = 30 J/molK(2)-Ce, which, together with corresponding cusp-like magnetization anomaly, indicate antiferromagnetic (AFM) ground state with Nel temperature T-N = 0.18 K. Numerical calculations based on Heisenberg model reproduce well zero field specific heat data, and point to a very small Kondo scale T-K clearly placing Ce4Pt12Sn25 in the weak exchange coupling J < J(c) limit of the Doniac diagram. Magnetic field suppresses AFM state at H* approximate to 0.7 T, much more rapidly than indicated by theoretical calculations.