Thermal Conductivity and Lorenz Function of Gadolinium between 5° and 310°K

Abstract

The thermal conductivity (λ) of a polycrystalline gadolinium sample, having an electrical resistivity of 2.41 μΩ cm at 4.18°K, has been studied as a function of temperature (T) between 5° and 310°K. The thermal conductivity has a maximum value of 0.333 W cm−1 °K−1 at 16.5°K. Changes in the slope of the λ vs T curve occur at 230° and 270°K. The former is believed due to the rapidly varying easy cone of magnetization. The second anomaly is associated with the ferromagnetic-paramagnetic transformation. The Lorenz function, from measured thermal conductivity and electrical resistivity data on the same sample, has been calculated as a function of temperature. This function clearly indicates that in addition to the electronic thermal conductivity there is considerable phonon and possibly some magnon heat transport.