Articolo in rivista, 2007, ENG, 10.1103/PhysRevB.75.235109

Temperature-independent ytterbium valence in YbGaGe

Doyle, BP; Carleschi, E; Magnano, E; Malvestuto, M; Dee, AA; Wills, AS; Janssen, Y; Canfield, PC

CNR, INFM, Lab Nazl TASC, I-34012 Basovizza, TS, Italy; Univ Trieste, Dipartmento Fis, I-34127 Trieste, Italy; Sincrotrone Trieste SCpA, I-34012 Basovizza, TS, Italy; Univ Coll London, Dept Chem, London WC1H 0AJ, England; Royal Inst Great Britain, Davy Faraday Res Lab, London W1S 4BS, England; Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France; Iowa State Univ, Ames Lab, Ames, IA 50011 USA

We have determined the ytterbium valence as a function of temperature in the reported near-zero thermal expansion material YbGaGe using x-ray photoemission at various incident photon energies. The Yb 3d, 4d, and 4f levels, which directly yield the Yb valence, have been measured. Careful analysis enabled the clear separation of surface and bulk contributions. Resonant photoemission at the 4d-4f absorption edge was used to enhance the low contribution of the Yb3+ component. Contrary to the initially proposed Yb valence transition, we find no change in the valence from room temperature down to 115 K.

Physical review. B, Condensed matter and materials physics 75

Keywords

ZERO THERMAL-EXPANSION, X-RAY SOURCE, YB COMPOUNDS, PHOTOEMISSION-SPECTROSCOPY, SINGLE-CRYSTALS

CNR authors

Carleschi Emanuela, Doyle Bryan Patrick, Magnano Elena

CNR institutes

INFM – Centro di responsabilità scientifica INFM