Mixed Valence Properties of CeM 2 Si 2 (M  Mn, Fe, Co, Ni, Cu)

Lattice parameter measurements in the temperature range 12 to 300 K and L III edge measurements in the range 4.2 to 300 K are performed on the compounds CeM 2 Si 2 (M Mn, Fe, Co, Ni, Cu) to study the valence changes. Magnetic measurements (1.6 to 600 K) for fields up to 1 T confirm antiferromagnetism of CeMn 2 Si 2 ( T N ≈ 370 K) and show enhanced Pauli paramagnetism of mixed valence compounds with M Fe, Co, Ni with spin fluctuation temperatures around 150 K with Co, Ni. Transport properties measurements show that the compounds with M Co, Ni, Fe do not become superconducting down at 18 mK and that a Fermi liquid behaviour exists in the range 40 to 70 K.