Thermoelectric determination of electronic entropy change in Ni-doped FeRh

TL;DR

This study experimentally evaluates the electronic entropy change in Ni-doped FeRh using heat capacity, Seebeck effect, and Hall measurements, revealing magnetic field dependence of electronic entropy.

Contribution

It provides the first comprehensive experimental analysis of electronic entropy change in Ni-doped FeRh across a magnetic transition using multiple thermoelectric methods.

Findings

Electronic entropy change .9 J/kgK from heat capacity

Seebeck coefficient indicates up to 4 J/kgK entropy change

Electronic entropy increases by 10% at 6 T magnetic field

Abstract

The net entropy change corresponding to the charge carriers in a Ni-doped FeRh bulk polycrystal was experimentally evaluated in a single sample using low temperature heat capacity experiments with applied magnetic field, and using Seebeck effect and Hall coefficient measurements at high temperatures across the first order transition. From the heat capacity data a value for the electronic entropy change \(\Delta S_{el}\approx8.9\) J\ kg\(^{-1}\)K\(^{-1}\) was extracted, whereas a value of up to 4 J\ kg\(^{-1}\)K\(^{-1}\) was obtained form the Seebeck coefficient. Additionally, the analysis of the Seebeck coefficient allows tracing the evolution of the electronic entropy change with applied magnetic field. An increase of the electronic entropy with increasing applied magnetic field is evidenced, as high as 10 percent at 6 T.