Perpustakaan Digital ITB

Figure of merit characterizations for thermoelectric materials were investigated. Resistivity, thermopower and thermal conductivity temperature-dependent measurements by incorporating the CTI-Cryogenic Model 350 CP closed-cycle He refrigerator system were performed. The design was carried out by LabVIEW 8.0 for computer controlled automatic measurement through GPIB interface within the temperature range from 50 K to 300 K after the chamber is vacuumized down to 10(-6)mbar. Generally, transport measurements are done by providing an external perturbation to the sample and measuring the response of the sample. In our case, the external perturbation is voltage source for resistivity measurements and heat supply for thermopower and thermal conductivity measurements. The response is either an electrical voltage and a heat gradient over the sample. We use standard copper for calibration of the setup which resistivity, thermopower and thermal conductivity were already determined precisely from the reference. From the calculation result of ZT, copper has the high value near 300 K, which is 0.6.