Preparation and chemical properties of the skutterudites (Ce-Yb) {sub y}Fe{sub 4-x}(Co/Ni) {sub x}Sb{sub 12}

Journal Article · Tue Mar 08 00:00:00 EST 2005 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2004.10.023· OSTI ID:20889751

Berardan, D ^[1]; Alleno, E ^[1]; Godart, C ^[1]; Rouleau, O ^[1]; Rodriguez-Carvajal, J ^[2]

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1. Laboratoire de Chimie Metallurgique des Terres-Rares, ISCSA-CNRS, 2-8 rue Henri Dunant 94320 Thiais (France)
2. Laboratoire Leon Brillouin, CEA-CNRS, Centre d'etudes de Saclay, 91191 Gif sur Yvette (France)

The double-filled skutterudites Ce {sub y/2}Yb {sub y/2}Fe{sub 4-x}Co {sub x}Sb{sub 12} and Ce {sub y/2}Yb {sub y/2}Fe{sub 4-x}Ni {sub x}Sb{sub 12} have been synthesized as single phase materials. The evolution of the lattice parameters and of the filling fractions with substitutions on the transition metal site have been studied by X-ray diffraction and electron probe microanalysis, respectively. Both results were compared to that of single filled series (Ce/Yb) {sub y}Fe{sub 4-x}(Co/Ni) {sub x}Sb{sub 12}. It shows that double-filled skutterudites can be understood as a solid solution between single filled ones. The valence states of Ce and Yb in all series have been studied using X-ray absorption spectroscopy at the L{sub 3} edges, and we discuss their relationships with structural parameters. Ce is always trivalent, whereas Yb valence state decreases as Yb fraction increases. No distortion of the environment or sub-position of Yb in the cage have been seen by neutron diffraction. The Seebeck coefficient has been measured using a home made apparatus from 120 K to 300 K. It shows a crossover from p- to n-type conductivity for Co or Ni rich skutterudites in the six series. We discuss the influence on the room temperature thermopower of valence states, filling fractions and substitution rate on the transition metal site. Thermopower seems to be only driven by charge carriers concentration.

• OSTI ID: 20889751
• Journal Information: Materials Research Bulletin, Vol. 40, Issue 3; Other Information: DOI: 10.1016/j.materresbull.2004.10.023; PII: S0025-5408(04)00342-3; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
CHARGE CARRIERS
CHEMICAL PROPERTIES
COMPLEXES
ELECTRICAL PROPERTIES
ELECTRON MICROPROBE ANALYSIS
INTERMETALLIC COMPOUNDS
LATTICE PARAMETERS
NEUTRON DIFFRACTION
SEMICONDUCTOR MATERIALS
SOLID SOLUTIONS
TEMPERATURE RANGE 0273-0400 K
TRANSITION ELEMENTS
VALENCE
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY