XRD, AC susceptibility and DSC studies of PrMn2-xNixGe2 compounds

X-ray powder diffraction, AC susceptibility and differential scanning calorimetry (DSC) studies were performed on the polycrystalline PrMn2-xNixGe2 (0less than or equal toxless than or equal to1) compounds. Substitution of Ni for Mn leads a linear decrease in the lattice constant c and the unit cell volume, while it gives rise a change of magnetic properties from ferromagnetic to anti-ferromagnetic behavior for small values of x<1. The samples with x=0.8 and 1.0 have a Neel temperature of about 33 K and 35 K, respectively. The samples with low Ni concentration are ferromagnetic and show an additional increase in the susceptibility. The substitution of nonmagnetic Ni for Mn weakens strength of the molecular field acting on Mn layers, yielding decrease of Curie temperature. The results lead to the construction of the partial x-T magnetic phase diagram. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.