Effect of magnetic ordering on the infrared spectra of holmium

Abstract In lanthanides, such as holmium, ordering of the local magnetic moments strongly affects the scattering rate of the conduction electrons (Kondo lattice). We performed infrared measurements on single crystalline holmium in a range from 1.2 meV to 1.2 eV at temperatures between 5 and 300 K. In the ordered state a reduced scattering rate in the Drude regime reflects the decrease of phonon as well as magnetic scattering. We observe an exchange splitting of 372 meV at the Fermi level and a low-frequency feature at about 37 meV.