title: Experimental investigation of the electronic structure of Gd(5)Ge(2)Si(2) by photoemission and x-ray absorption spectroscopy.
abstract: The electronic structure of the magnetic refrigerant Gd(5)Ge(2)Si(2) has been experimentally investigated by photoemission and x-ray absorption spectroscopy. The resonant photoemission and x-ray absorption measurements performed across the Gd N(4,5) and Gd M(4,5) edges identify the position of Gd 4f multiplet lines, and assess the 4f occupancy (4f(7)) and the character of the states close to the Fermi edge. The presence of Gd 5d states in the valence band suggests that an indirect 5d exchange mechanism underlies the magnetic interactions between Gd 4f moments in Gd(5)Ge(2)Si(2). From 175 to 300 K the first 4 eV of the valence band and the Gd partial density of states do not display clear variations. A significant change is instead detected in the photoemission spectra at higher binding energy, around 5.5 eV, likely associated to the variation of the bonding and antibonding Ge(Si) s bands across the phase transition.
authors.affiliation: Laboratorio Nazionale TASC INFM-CNR, Basovizza-Trieste, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Bondino
authors.forename: A
authors.initials: A
authors.lastname: Brinkman
authors.forename: M
authors.initials: M
authors.lastname: Zangrando
authors.forename: F
authors.initials: F
authors.lastname: Carbone
authors.forename: D
authors.initials: D
authors.lastname: van der Marel
authors.forename: D L
authors.initials: DL
authors.lastname: Schlagel
authors.forename: T A
authors.initials: TA
authors.lastname: Lograsso
authors.forename: K A
authors.initials: KA
authors.lastname: Gschneidner
authors.forename: V K
authors.initials: VK
authors.lastname: Pecharsky
authors.forename: F
authors.initials: F
authors.lastname: Parmigiani