A straightforward 2$\omega$ technique for the measurement of the Thomson effect

TL;DR

This paper introduces a simple, fast, and precise 2ω technique for measuring the Thomson coefficient in thermoelectric materials using dynamical heating and harmonic analysis.

Contribution

The paper presents a novel 2ω measurement method for the Thomson effect that improves accuracy and speed over existing techniques.

Findings

Method accurately measures Thomson coefficient in platinum and nickel.

Second harmonic response is proportional to the Thomson coefficient.

Analytical and numerical models identify key sources of measurement error.

Abstract

We present a simplified, rapid, and accurate method for the measurement of the thermoelectric Thomson coefficient by the dynamical heating of a suspended wire by an alternating current. By applying a temperature gradient across the wire, we find that the response at the second harmonic of the excitation frequency is directly proportional to the Thomson coefficient. The absolute thermoelectric coefficient of a single material can therefore be extracted with high precision by a phase sensitive detector. We test our method on platinum and nickel wires and develop both analytical and numerical models to determine the leading sources of error.