Simultaneous measurements of thermopower, thermal conductivity, and electrical resistivity between 1.2 and 350 K

We described a fast‐cooling cryostat with a novel cooling system using a nitrogen heat pipe. The principal feature of the cryogenic assembly is an evacuated calorimeter containing a heat sink which can be maintained successively at 1, 4.2, and 77 K during the experiment. This allows sample regulation from 1.5 to 350 K. An electronic circuit including noise filters and nanovoltmeters is used to measure the electrical resistivity, thermal conductivity, and thermoelectric power of conducting or semiconducting materials. We used a commercially available Au–Fe–chromel couple as the working thermocouple. First, we calibrated it against germanium and platinum resistance thermometers, and compared the thermoelectric scale so obtained with previous calibrations. We report a preliminary test on pure lead which enabled us to obtain the absolute thermoelectric powers of AuFe and chromel and also to estimate the parasitic radiative heat transfer during thermal conductivity measurements. We also report the three transport properties of the title for an amorphous Ce0.3Al0.7 alloy prepared by sputtering a crystalline CeAl3 compound. The thermal conductivity and electrical resistivity were essentially those associated with amorphous materials. The thermoelectric power exhibited structure at low temperatures which suggests that a weak magnetism appeared in this glassy structure formed from the typical Kondo compound CeAl3.