title: Infrared spectroscopy and the ferromagnetic transition in Gd.
abstract: The low energy electronic structure of Gd has been investigated experimentally by infrared reflectance spectroscopy, and theoretically from first principles, using the fully relativistic Dirac linear-muffin-tin-orbital (LMTO) method in the local spin density approximation (LSDA) as well as within the LSDA + U approach. The reflectance of a Gd single crystal was measured with the electric field in the plane perpendicular to the c-axis for temperatures between 50 K and slightly above the Curie temperature (293 K) in the frequency range between 100 and 12 000 cm(-1) (0.013-1.5 eV). As Gd enters the ferromagnetic state, the dissipative part of the optical conductivity exhibits interesting spectral weight transfers over the whole spectral range measured. It is shown that the ab initio calculations reproduce well the experimental spectra for the ferromagnetic state and allow one to explain the microscopic origin of the optical response of Gd in terms of interband transitions.
authors.affiliation: Department of Physics, Brock University, St. Catharines, ON, L2S 3A1, Canada.
authors.forename: L H
authors.initials: LH
authors.lastname: Obied
authors.forename: D A
authors.initials: DA
authors.lastname: Crandles
authors.forename: V N
authors.initials: VN
authors.lastname: Antonov
authors.forename: S K
authors.initials: SK
authors.lastname: Bose
authors.forename: O
authors.initials: O
authors.lastname: Jepsen
mesh_terms: D018360:Crystallography, X-Ray; D005682:Gadolinium / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry*; D008962:Models, Theoretical; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014732:Vibration
chemical_list: D005682:Gadolinium