Anomalous behavior of physical properties in RMg2Ni9 (R = Ce and Pr) with a two-dimensional rare earth arrangement

We performed the magnetic susceptibility, electrical resistivity and specif ic heat measurements on the new compounds RMg2Ni9 (R = Ce and Pr) crystalli zed in a PuNi3-type hexagonal. The results indicate that CeMg2Ni9 is a typi cal valence fluctuated compound with gamma = 80 mJ/mol CeK2, but it shows n either the - ln T dependence in the rho-T curve nor any broad peak in %-T c urve. It seems likely that the unusual physical properties of RMg2Ni9 are i nfluenced by the two dimensionality of the rare earth arrangement. (C) 1999 Elsevier Science B.V. All rights reserved.