Thermal Conductivity of Polycrystalline Dysprosium from 5 to 305°K

Thermal conductivity of polycrystalline dysprosium has been studied between 5 and 305^∘{}K. An abrupt decrease in the thermal conductivity occurs at the ferromagnetic-antiferromagnetic transformation. The transition from the antiferromagnetic to the paramagnetic state causes a gradual increase in the thermal conductivity with increasing temperatures. The Lorenz number of dysprosium has been calculated as a function of temperature. It is concluded that in addition to the electronic thermal conductivity there is considerable lattice conductivity and possibly some magnon conductivity. An apparatus for determining the thermal conductivity of solids from liquid-helium to room temperatures is briefly described.