High temperature transport probe for thermopower and resistivity measurements

We have recently developed a device to measure resistivity and Seebeck values of a material as a function of temperature over a range of 80K < T < 700K. These measurements overlap in temperature with our existing apparatus (4K < T < 320K). These measurements are necessary for the investigation of potential thermoelectric materials at elevated temperatures, where power generation applications are important. The probe design allows for various types of samples to be evaluated from needle like samples ( L approximate to 2mm, D approximate to 50 mu m) to larger pressed pellet samples ( approximate to 2mm x 2mm x 10mm). Separate high temperature cartridge heaters are used to stabilize both the absolute temperature, T, as well as the temperature difference, Delta T. Thermocouples measuring T+Delta T/2 and T-Delta T/2 are also employed to measure sample voltages for resistance and thermoelectric power. Design details and measurement specifics will be discussed. Data taken on standards a well as some research samples will be presented.