Superparamagnetic and metal-like Ru2TiGe: a propitious thermoelectric material

TL;DR

This study investigates Ru2TiGe, a Heusler alloy, revealing its superparamagnetic behavior at low temperatures and promising thermoelectric properties with a ZT of 0.025 at 390 K, indicating potential for thermoelectric applications.

Contribution

It provides the first detailed analysis of the magnetic and thermoelectric properties of Ru2TiGe, highlighting its high power factor and low thermal conductivity for thermoelectric use.

Findings

Superparamagnetic interactions dominate below 20 K.

Large Seebeck coefficient yields high power factor.

ZT value of 0.025 at 390 K suggests thermoelectric potential.

Abstract

We report a study of structural, magnetic, heat capacity and thermoelectric properties of a Rubased Heusler alloy, Ru2TiGe. The magnetic measurements reveal that at higher temperatures, diamagnetic and Pauli paramagnetic contributions dominate the magnetic behaviour whereas, at lower temperatures (T<= 20 K), superparamagnetic interaction among clusters is observed. Effect of such magnetic defects is also evident in the electrical resistivity behaviour at lower temperatures. Though the temperature dependence of resistivity exhibits a metal-like nature, the large value of Seebeck coefficient leads to an appreciable power factor of the order of 1 mW/mK2 at 300 K. Large power factor as well as low thermal conductivity results in a value of ZT = 0.025 at 390 K for Ru2TiGe that is orders of magnitude higher than that of the other pure Heusler alloys and point towards its high potential for practical thermoelectric applications.