Magnetic interactions in Pr1-xTbxMn2Ge2

The magnetic moments in the rare earth and Mn sublattices of RMn2Ge2, where R is a rare earth element, feature a variety of ordering configurations. In PrMn2Ge2 and TbMn2Ge2, the interlayer magnetic coupling in the Mn sublattice is, respectively, ferromagnetic and antiferromagnetic below about 350 K. At low temperatures, the rare earth sublattice also orders and reconfigures the ordering in the Mn sublattice. In this study, we investigate the variations in the magnetic properties of Pr1-xTbxMn2Ge2 as a function of rare earth concentration by examining the evolution of the features in the temperature dependence of the magnetization. The results of earlier neutron diffraction and Mossbauer studies on samples with x = 0 and 1 are also used for interpreting the magnetization data and to give an account of the competing effects between various magnetic structures in the Mn and rare earth sublattices. The results are summarized in the Pr1-xTbxMn2Ge2 magnetic phase diagram. (C) 2002 Elsevier Science B.V. All rights reserved.