9:30 AM - 9:45 AM
▲ [21a-C102-3] Role of contact pad on the local heating during thermoelectric power measurements of Silver Chalcogenide subjected to unusual heating
Keywords:High Power Thermoelectric, Unusual heating, Spatial separation
Spatial phase separation was found to play a vital role in the recently observed colossal Seebeck effect along with metallic electric conduction in Ag2S under an unusual temperature gradient by G. Kim et al. In this configuration a high Seebeck coefficient of approx. –650 uVK-1 was observed along with a relatively low electrical resistivity (~ 2 mOhm-cm). The unique and uncommon measurement setup was designed and fabricated to impose spatial phase separation. This setup consists of two heaters, one of which is a usual heater and the other to induce a temperature gradient from between the bottom and top surface. This heater induces the coexistence of an insulating low-temperature phase at the top and a metallic high-temperature phase at the bottom. The combination of these two-layered phases could considerably fuel the power factors to higher values.
We realized that a straightforward measurement of power generation from Ag2S is challenging due to the non-trivial Peltier effect and Joule heating at the junctions of the sample and the contact leads. Modification of the temperature control loop helped to extract the tip effect. In addition, palladium paste was used to fabricate the contact pad of lead wires/thermocouples to avoid the convergence of electrical current. We confirmed that the pad size at the contacts possesses a significant effect on the heating/cooling of the tip of thermocouples during the power measurements. Different probe arrangements and heater positions were also employed to perform the more reliable measurements of power generation from Ag2S by significantly reducing the local heating/cooling in association with the electrical current convergence.
We realized that a straightforward measurement of power generation from Ag2S is challenging due to the non-trivial Peltier effect and Joule heating at the junctions of the sample and the contact leads. Modification of the temperature control loop helped to extract the tip effect. In addition, palladium paste was used to fabricate the contact pad of lead wires/thermocouples to avoid the convergence of electrical current. We confirmed that the pad size at the contacts possesses a significant effect on the heating/cooling of the tip of thermocouples during the power measurements. Different probe arrangements and heater positions were also employed to perform the more reliable measurements of power generation from Ag2S by significantly reducing the local heating/cooling in association with the electrical current convergence.