Composition and temperature dependence of the thermoelectric power of Ni$_{2+x}$Mn$_{1-x}$Ga alloys

TL;DR

This study investigates how the thermoelectric power of Ni$_{2+x}$Mn$_{1-x}$Ga alloys varies with temperature and composition, revealing insights into electronic structure changes during phase transitions.

Contribution

It provides new experimental data on TEP behavior across different compositions and links these changes to microstructural and electronic structure modifications.

Findings

TEP varies with temperature and Ni content.

Electronic density of states changes are linked to Jahn-Teller distortions.

Microstructural transitions influence thermoelectric properties.

Abstract

The thermoelectric power (TEP) measurements have been carried out to investigate the changes in the electronic structure associated with the intermartensitic and martensitic transitions in Ni$_{2+x}$Mn$_{1-x}$Ga (0 $\le$ x $\le$ 0.19). The samples have been characterized by a.c. magnetic susceptibility measurements. The correlation between the TEP and the microstructural changes sensitive to the increasing Ni content in Ni$_{2+x}$Mn$_{1-x}$Ga has been investigated. The changes in the density of states as reflected in the temperature variation of the TEP are consistent with the conclusions drawn from the Jahn-Teller mechanism of lattice distortion.