Multiple magnetic transitions and anomalous magnetism in Tb2CuGe3

We report the formation of a compound, Tb2CuGe3, in a AlB2-derived hexagona l structure and its magnetic characteristics by electrical resistance (1.4- 300 K), magnetization (2-300 K) and heat-capacity (2-50 K) measurements. Th e results establish that there is an onset of antiferromagnetic ordering at a temperature close to 19 K, which is much larger than the de Gennes scale d value. The data also present evidence for additional magnetic transitions at lower temperatures, say at about 13 and 8 K, which also appear to be of antiferromagnetic type, however, with possible differences in the Fermi su rfaces/magnetic structure. These results characterize that this compound is an interesting magnetic system. (C) 2001 Elsevier Science Ltd. All rights reserved.