LARGE LOW-TEMPERATURE MAGNETORESISTANCE AND MAGNETIC-ANOMALIES IN TB2PDSI3 AND DY2PDSI3

The results of heat-capacity (C), magnetic susceptibility (chi), elect rical resistivity (rho) and magnetoresistance (Delta rho/rho) measurem ents on the compounds, Tb2PdSi3 and Dy2PdSi3, are reported. The result s establish that these compounds undergo long-range magnetic ordering (presumably with a complex magnetic structure) below (T-c =) 23 and 8 K, respectively. The Delta rho/rho is negative in the vicinity of T-c and the magnitude grows as T-c is approached from higher temperatures as in the case of well-known giant magnetoresistance systems (La manga nite-based perovskites); this is attributed to the formation of some k ind of magnetic polarons. The magnitude of Delta rho/rho at low temper atures is quite large, for instance, about 30% in the presence of 60 k Oe field at 5 K in Dy sample. (C) 1998 Elsevier Science Ltd. All right s reserved.