Instrument for simultaneous measurement of Seebeck coefficient and thermal conductivity in the temperature range...

Fabrication and characterization of an instrument for the high-temperature simultaneous measurement of the Seebeck coefficient (S) and thermal conductivity (κ) have been carried out with Python automation. The steady-state-based Fourier's law of thermal conduction is employed for κ measurement. The parallel thermal conductance technique is implemented for heat loss measurement. Introducing a thin heater and insulating heater base minimizes the heat loss and makes it easier to arrive at high temperatures. Measurement of S is carried out using the differential method. The same thermocouples are used to measure the temperature as well as voltage for S measurement. Care of temperature dependent S of the thermocouple has also been taken. Simple design, small size, and lightweight make this instrument more robust. All the components for making a sample holder are easily available in the market and can be replaced as per the user's demand. This instrument can measure samples with various dimensions and shapes in the temperature range 300-800 K. The instrument is validated using different classes of samples, such as nickel, gadolinium, Fe₂VAl, and LaCoO₃. A wide range of S values from ∼-20 to ∼600 μV/K and κ values from ∼1.1 to ∼23.5 W/m K are studied. The measured values of S and κ are in good agreement with the reported data.