An Analysis for Measurement of Thermal Diffusivity Components of Anisotropic Platelike Samples by AC Calorimetric Method

Abstract

This work examines the effects of anisotropy and transparency on measurements of thermal diffusivity components with an ac calorimetric method associated with laser heating. Analytical results indicate that the region where the two-dimensional effect occurs increases with the decrease of the ratio of cross-plane to in-plane thermal diffusivity. The region also increases with the optical thickness of the sample. The linear relations, as indicated by a decay constant from which the cross-plane thermal diffusivity is deduced, are not obtained for media of both optically moderate and thin thickness, while at sufficiently large optical thickness, anisotropy and two-dimensional effects are found insignificant.

High-Temperature Thermoelectric Properties of NaxCoO2-δ Single Crystals

“…The in-plane thermal diffusivity was estimated by the ac calorimetric method associated with optical pulse heating. [13][14][15] The reliability of the measurements was confirmed by measuring the relevant properties of nickel as a reference.…”

Interlayer thermal conductivity of rubrene measured by ac-calorimetry

“…If the sample is sufficiently thin 13,19 (e.g. d<<L,w) and the light is absorbed uniformly on the surface, the heat flow will be one-dimensional and, if  >>1/ 1 , the magnitude of the oscillating temperature on the back surface is given by 16 :…”

“…A number of frequency dependent techniques, in which oscillating power is applied to the sample and resulting temperature oscillations measured, have been developed to measure thermal conductivity of small samples. [7][8][9][10][11][12][13][14][15] For these, the power transported out of the sample by leads and radiation determines the "external" thermal time constant,  1 , but measurements are typically made at frequencies  >>1/ 1 , 8 so that heat loss and radiation corrections are negligible. 11 Perhaps the most widely used of ac-methods is the "3" technique, 11 in which oscillating power is applied to a Joule heater deposited on the sample and the temperature oscillations of the heater measured.…”

High-temperature thermoelectric properties of Na/sub x/CoO/sub 2-δ/ single crystals

“…The density was measured by the Archimedes method, and the heat capacity was measured by the differential scanning calorimeter. The in-plane thermal diffusivity was estimated by the ac calorimetric method associated with optical pulse heating [13][14][15].…”