Development of an Improved Probe Design and Analysis Method for Reliable Thermopower Measurements

Thermopower is a fundamental thermodynamic property that provides insight into the behavior of strongly correlated electron materials. Quantified by the Seebeck coefficient, this value represents the ratio of voltage generated over the temperature gradient applied across a sample. Previous thermopower measurements in our lab were hindered by lengthy experiments and complicated analysis [1]. To improve efficiency, we implemented a faster analysis technique known as the slope method and began directly regulating temperature (T) on the cold side thermometer. Testing with 99.9% platinum showed consistent results between the slope and steady-state methods under a temperature gradient ~3% above the regulated cold-side temperature, as well as agreement with literature above 80 K. Deviations below 80 K were attributed to the differential type T thermocouple which has limited resolution for low temperature measurements. These results confirm the slope method’s validity for faster, reliable thermopower measurements. To enhance sub-80 K accuracy, we developed a new probe incorporating a hot-side thermometer and simultaneous measurement of target and reference samples, enabling more precise removal of background contributions.

REF [1] A. Capa Salinas, et al. Proceedings of NCUR 2019, Page 171-177.