Development of an Absolute Measurement Technique for the Seebeck Coefficient using the Thomson Effect

Abstract

The Seebeck coefficient is the most widely measured property specific to thermoelectric materials. The absolute Seebeck coefficient S determined from the Thomson effect is highly sensitive to systematic errors incurred in the determination of the material thermal conductivity and geometry and heat loss from the sample to surroundings caused by temperature differences. Here, we review a technique for the precision measurement of S based on the Thomson effect using an AC-DC technique. This technique utilizes accurate equivalent-amplitude AC and DC currents, which can eliminate the need for acquiring accurate thermal conductivity and geometry values. These parameters can be replaced by the precisely and readily measurable parameters of electrical resistance and temperature changes caused by the Joule effect. The correction term of the heat loss owing to heat transfer via the thermocouple vanishes upon calculating the ratio of the measured temperature changes for both AC and DC excitations.