Experimental Setup for the Measurement of Low Temperature Seebeck Coefficient of Single Crystal and Bulk Materials

Abstract

A differential thermopower setup is fabricated for both the single crystal and bulk materials in the temperature range of 16–320 K. One advantage of this apparatus is that the sample separation can be changed according to the requirement between 2 and 5 mm. In this setup silver paint is used for the improvement of thermal and electrical conductivity between copper (thermocouple) leads and material. Seebeck coefficients are measured using a filter circuit at fixed temperature by making different temperature gradients for highly resistive compounds (<100 KW) and continuously with a temperature difference of 0.3–0.5 K in case of metallic compounds. This setup is calibrated by using the high purity lead material and used it for the calculation of absolute seebeck coefficient of materials of interest. Our calculated Seebeck coefficient of copper from the measurement value of lead differs from the standard value of copper by +1.4 μV/K with a transition around 41 K related to the silver contain.

Keywords: Thermo power, differential method, experimental design, computer automation