Measurements of the Seebeck Coefficient of Thermoelectric Materials by an AC Method

摘要

All ac method for measurement of the Seebeck coefficient was developed. Specimens were heated periodically at frequencies in the range 0.2-10 Hz using a semiconductor laser. The small temperature increase and the resultant ther- moelectric power were measured with a Pt-Pt 13/100, Rh thermocouple (25 μm in diameter) through a lock-in amplifier. The Seebeck coefficient of a Pt_(90)Rh_(10) foil measured by the ac method was in agreement with that obtained from the standard table. The optimum frequency and specimen thickness for the ac method were 0.2 Hz and 0.1-0.2 mm, respectively.