Observation of a temperature dependent electrical resistance minimum above the magnetic ordering temperature in Gd$_2$PdSi$_3$

TL;DR

This study reports a temperature-dependent electrical resistance minimum in Gd$_2$PdSi$_3$ occurring above its magnetic ordering temperature, likely caused by electron localization due to exchange interactions, and explores its suppression under magnetic fields.

Contribution

It presents the first observation of a resistance minimum above magnetic order in a Gd alloy, proposing a novel electron localization mechanism prior to magnetic ordering.

Findings

Resistivity shows a minimum at ~45 K above 21 K magnetic order

Magnetic field suppresses the resistance minimum

Electron localization via exchange interaction proposed as mechanism

Abstract

Results on electrical resistivity, magnetoresistance, magnetic Results on electrical resistivity, magnetoresistance, magnetic susceptibility, heat capacity and Gd Mossbauer measurements on a Gd-based intermetallic compound, Gd$_{2}$PdSi$_{3}$ are reported. A finding of interest is that the resistivity unexpectedly shows a well-defined minimum at about 45 K, well above the long range magnetic ordering temperature (21 K), a feature which gets suppressed by the application of a magnetic field. This observation in a Gd alloy presents an interesting scenario. On the basis of our results, we propose electron localization induced by s-f (or d-f) exchange interaction prior to long range magnetic order as a mechanism for the electrical resistance minimum.