Magnetic, specific-heat, and resistivity measurements of alloys CePd2-x+yMnxSi2-y (0 x2, -0.1y0.1)

Measurements of (a) the lattice parameters at room temperature, (b) the magnetic susceptibility in the temperature range 1.5 K<T<300 K, (c) the electrical resistivity from 4.2 to 300 K, and (d) the specific heat from 1.5 to 60 K have been performed on the pseudobinary system CePd2-xMnxSi2. In the intermediate concentration range the character of the magnetic behavior changes from 4f magnetism-due to the Ce magnetic moments oriented in the [110] direction in the Kondo-lattice system CePd2Si2 to 3d magnetism in the [001] direction carried by the Mn atoms without a magnetic moment at the Ce sites for CeMn2Si2. Both boundary compounds crystallize with ThCr2Si2 structure and order antiferromagnetically at 10 and 379 K, respectively. The values of the electronic specific heat show a strong enhancement in the intermediate composition range where the change of the magnetic character occurs; this points (together with a reduction of the entropy for CePd2Si2 at TN) to the appearance of spin fluctuations and/or Kondo scattering with screening of the Ce moments. Furthermore the Néel temperatures and the values sensitively depend upon the stoichiometry y in CePd2+ySi2-y.