Description of the parallel thermal conductance technique for the measurement of the thermal conductivity of small diameter samples

Abstract

In order to measure the thermal conductivity of small needlelike samples (2.0×0.05×0.1 mm3) such as pentatellurides and single carbon fibers, we have developed a new technique called the parallel thermal conductance (PTC) technique. In the more typical steady state method that is used for measuring thermal conductivity, thermocouples are attached to the sample in order to measure the temperature gradient and a heater in order to supply this gradient. However, attaching thermocouples and heaters directly to small samples may be relatively difficult, and cause large heat losses and errors. Thus, the measurement of the thermal conductivity of small samples and thin films has been a formidable challenge, with only few successes, due, among other factors, to the heat loss. It is also difficult for the small samples to support the heaters and thermocouples without causing damage to the sample. In this paper we describe the recently developed PTC method providing measurements on standards as well as single carbon fibers, in addition to preliminary pentatelluride crystals measurements.