A magnetic study of the ThCr2Si2-type RPd2Ge2 (R=Pr, Nd) compounds. Magnetic structure of PrPd2Ge2 from powder neutron diffraction

The magnetic properties of the PrPd2Ge2 and NdPd2Ge2 compounds have been investigated by magnetic measurements, specific heat measurements and neutron diffraction experiments. The PrPd2Ge2 compound orders antiferromagnetically below TN=5.0(2) with an original modulated magnetic structure characterized by a magnetic cell three times larger than the chemical one by tripling of the c parameter. The palladium atom is non magnetic and the Pr moments are parallel to the c-axis with a value of ≈2.0 μB at 2 K. The specific heat measurements clearly detect a low temperature transition for the NdPd2Ge2 compound, interpreted as a Nd sublattice antiferromagnetic ordering below 1.3(2) K.