Seebeck Coefficient Measurement Probe by Using a Differential Thermocouple

When a temperature gradient is imposed at the ends of a conducting material, a voltage will be generated on this material. This phenomenon is known as the Seebeck effect and is characterized by the Seebeck coefficient. Thermopower, or Seebeck coefficient measurements, can provide a deeper understanding of the properties of a sample, its normal state behavior, and help progress on applications, such as thermoelectric generators, cooling systems, and temperature measurement devices. The samples of interest for thermopower measurements in our lab are filled-skutterudite compounds, for they exhibit thermoelectric effects. For this purpose, a thermopower measurement probe was designed and its resolution tested using Nickel 201 alloy and platinum samples. It was concluded that the device provides measurements within 3% error in the 100K-300K range. However, measurements bellow 100K must be improved, since current data indicates measurements are limited by the operating range of the type-T thermocouple used. Thus, future improvement will consist of adding a Cernox thermometer on the hot platform to account for a more accurate temperature difference at low temperatures.