LOCAL AND ITINERANT MAGNETISM AND CRYSTAL-STRUCTURE OF RRH2GE2 AND RRU2GE2 (R = RARE-EARTH)

The compounds RRh//2Ge//2 and RRu//2Ge//2 were synthesized. X-ray studies show that they have the expected ThCr//2Si//2 tetragonal-type structure. Magnetization studies at 1. 8-300 K, **1**5**1Eu Mossbauer studies at 4. 1, 77 and 300 K and the crystallography studies show the following: All RRh//2Ge//2 like RRh//2Si//2 exhibit two magnetic phase transitions, one corresponding to the antiferromagnetic ordering of the local rare earth moments, T//N equals 8-90 K, the other corresponding to the itinerant electron ordering of the Rh sublattice, T//M equals 3-9 K. The heavy rare earths in RRu//2Ge//2 order antiferromagnetically and undergo a spin-flop transition in a relatively low magnetic field, less than 10koe. The light elements in RRu//2Ge//2 order in a ferromagnetic, somewhat unclear structure.