Simultaneous Measurement of Low-Temperature Specific Heat and Thermal Conductivity by Temperature-Wave Method

Abstract

An experimental procedure is proposed for a simultaneous measurement of thermal conductivity and thermal diffusivity of a specimen by a modified temperature-wave (Ångström's) method. The temperature wave is generated by an AC current in a heater attached to the specimen. The diffusivity can be obtained from the phase difference of the temperature wave between two positions of the specimen, and the conductivity is determined from the static temperature gradient produced by the DC component of input power. The temperatures and their variation at two positions are detected by carbon film resistance thermometers. The specific heat of the specimen is derived from the values of thermal diffusivity and conductivity. An example of experimental results is given for the case of Cu-Al alloy specimen. The reliability of the measured values of conductivity and diffusivity is estimated to be 5∼8% in liquid-helium temperature range.