Design, fabrication and calibration of low cost thermopower measurement set up in low- to mid-temperature range

The Seebeck coefficient, in combination with electrical and thermal conductivity, enables the evaluation of thermoelectric performance of the functional materials. A compact thermopower measurement set up, capable of carrying out the measurements in the mid-temperature range (300-700 K), has been designed, developed and fabricated in-house. The set-up is calibrated first by performing the measurement of thermopower of constantan, alumel, and chromel specimen (reference material) at 313 K. The two data sets obtained on the sample of CaMnO3 in the temperature range of 300-700 K, using the presently developed set-up and a commercial set-up (M/s LINSIES, Model LSR 3), are in fair agreement. The error in the measurement of Seebeck coefficient in the presently developed apparatus is estimated to be less than 5% in the entire temperature range. The instrument design and method of data acquisition have been presented in detail.