Magnetic properties of RMn2Ge2 compounds (R=La, Ce, Pr, Nd, Cd, Tb, Dy, Ho, Er, and Th)

Abstract

Magnetic properties RMn₂Ge₂ compounds where R is La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, and Th have been investigated from 4.2 to 500 K. LaMn₂Ge₂, CeMn₂Ge₂, PrMn₂Ge₂, and NdMn₂Ge₂ are ferromagnetic with Curie temperatures of 306, 316, 334, and 334 K, respectively. The heavy rare‐earth compounds do not order ferromagnetically until low temperatures. GdMn₂Ge₂ shows a sharp magnetic transition at 97 K both in the magnetization‐vs‐temperature and resistivity‐vs‐temperature data. For this compound, it is proposed that above 97 K the Mn moments order antiferromagnetically among themselves while the Gd moments are disordered. Below 97 K the Mn moments couple ferromagnetically with each other but are opposed to the ordered Gd sublattice. Magnetic moment obtained at 4.2 K can be explained for all the compounds on the basis of an antiferromagnetic coupling between Mn and rare‐earth spins.