Large Low Temperature Magnetoresistance and Magnetic Anomalies in Tb$_2$PdSi$_3$ and Dy$_2$PdSi$_3$

TL;DR

This study investigates the magnetic and magnetoresistive properties of Tb$_2$PdSi$_3$ and Dy$_2$PdSi$_3$, revealing large low-temperature magnetoresistance linked to magnetic ordering and polaron formation.

Contribution

It provides new insights into the magnetic ordering and giant magnetoresistance phenomena in these rare-earth compounds at low temperatures.

Findings

Magnetic ordering occurs below 23 K in Tb and 8 K in Dy compounds.

Negative magnetoresistance increases near the magnetic transition temperature.

Magnetoresistance reaches about 30% at 5 K under 60 kOe in Dy$_2$PdSi$_3$.

Abstract

The results of heat-capacity, magnetic susceptibility, electrical resistivity and magnetoresistance $(\Delta \rho/\rho)$ measurements on the compounds Tb$_2$PdSi$_3$ and Dy$_2$PdSi$_3$, are reported. The results establish that these compounds undergo long-range magnetic ordering (presumably with a complex magnetic structure) below (Tc=) 23 and 8 K respectively. The $\Delta \rho/\rho $ is negative in the vicinity of Tc and the magnitude grows as Tc is approached from higher temperature as in the case of well-known giant magnetoresistance systems (La manganite based perovskites); this is attributed to the formation of some kind of magnetic polarons. The magnitude of magnetoresistance at low temperatures is quite large, for instance, about 30% in the presence of 60 kOe field at 5 K in the Dy sample.