## ac-Calorimetric Measurement of Transverse Thermal Conductivity    [PDF]

H. Zhang, J. W. Brill
We discuss how ac-calorimetry, commonly used to measure heat capacities of thin samples, can be used to measure the thermal diffusivity, and therefore the thermal conductivity, {\kappa}, along the thickness of the sample. We discuss the various limitations of the technique, which is best suited for materials with small diffusivities, such as layered materials for which the interlayer thermal conductivity can be very small. Examples are shown for two polymeric materials, PTFE (teflon) and PMMA (plexiglass), in which our values of {\kappa} are somewhat smaller than those observed by others, and crystalline sapphire and rubrene. For the latter, the interlayer thermal conductivity is almost an order of magnitude smaller than the in-layer value, but its temperature dependence indicates that the interlayer mean free path is at least a few layers.
View original: http://arxiv.org/abs/1304.7305