Designing thermopower measurement probe*

The conversion of electrical energy into thermal energy and vice versa is called the thermoelectric effect, and it can be characterized by one of the effects known as the Seebeck effect. This effect can be determined by the Seebeck coefficient, which is measured by the electrical voltage developed across the conducting or semiconducting materials when temperature differences are applied at the ends of these materials. The Seebeck coefficient may be negative or positive, depending on the type of charge carriers: electrons or holes. This effect can be useful in power generation, thermocouples for temperature control or pressure monitoring, and many other industrial applications. Many strongly correlated electron materials exhibit a thermoelectric effect. Therefore, the Seebeck coefficient is an important physical property to be monitored. Experimental results of the thermopower values from the previous probe design show that the performance of the measurements needs improvement below 100K. This is due to the limitations of the type T differential thermocouple and the inefficiency of subtracting background from only one sample holder. In the new probe design, we plan to implement two Cernox thermometers on the hot side platform and the cold side platform. In addition to this, we are modifying the probe design to run the measurements simultaneously for two sample holders to efficiently subtract off the background contributions. We will use nickel 201 alloy and platinum as standard reference materials to check the accuracy of our new thermopower probe.