Anomalous Thermal Conductivity of the Rare Earth Metals—Gadolinium, Terbium, and Dysprosium

Abstract

Recent measurements of the thermal (K) and electrical (σ) conductivities of the rare earth metals (gadolinium, terbium, and dysprosium), indicate that the ratio Kσ−1 T−1 is considerably larger than the value predicted by the Wiedemann-Franz law. At low temperatures, a significant lattice contribution to the thermal conductivity (and possibly some magnon contribution) seems to account for the experimental results. At higher temperatures, the bipolar mechanism of heat transport is probably responsible for the observed behavior. If this interpretation is correct, other transport properties should exhibit anomalous behavior. In particular, the Nernst and Ettingshausen effects should be anomalously large and therefore these rare earth metals may be useful in devices for refrigeration or electrical power generation.