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.