COMPLEX MAGNETISM IN A NEW ALLOY, EU2PDSI3, WITH 2 CRYSTALLOGRAPHICALLY INEQUIVALENT SITES

Lattice constants, electrical resistivity, heat capacity, AC and DC ma gnetic susceptibility and Eu-151 Mossbauer effect studies on a new int ermetallic compound, Eu2PdSi3, found to crystallize in an AlB2-derived hexagonal crystal structure, are reported. The results establish that the Eu ions are in the divalent state down to low temperatures, under going two magnetic transitions, one at 40 K and the other at 10 K, per taining to two different Eu sites. Interestingly, the minority Eu ions at the 2(b) sites order at a relatively high temperature (40 K) and t his magnetic interaction is inferred to be ferromagnetic and quasi one -dimensional along the c-axis. The magnetic structure below 5 K follow ing magnetic ordering (at 10 K) of the majority ions at 6(h) sites app ears to be quite complex. In short, the crystallographic and (hence) t he overall magnetic behaviors of this compound present an interesting situation. (C) 1998 Elsevier Science B.V. All rights reserved.