Melnychenkc-Koblyuk, N., Grytsiv, A., Rogl, P. F., Rotter, M., Bauer, E., Durand, G., Kaldarar, H., Lackner, R., Michor, H., Royanian, E., Koza, M., & Giester, G. (2007). Clathrate formation in the Ba-Pd-Ge system: Phase equilibria, crystal structure, and physical properties. Physical Review B, 76(144118). https://doi.org/10.1103/physrevb.76.144118
E136 - Institut für Theoretische Physik E138-03 - Forschungsbereich Functional and Magnetic Materials
-
Journal:
Physical Review B
-
ISSN:
2469-9950
-
Date (published):
31-Oct-2007
-
Number of Pages:
11
-
Publisher:
AMER PHYSICAL SOC
-
Peer reviewed:
Yes
-
Keywords:
Condensed Matter Physics; Electronic, Optical and Magnetic Materials
-
Abstract:
Phase relations at subsolidus temperatures as well as at T=800 °C, crystallographic data, electrical and thermal transport measurements, and heat capacity data are reported for several compositions within the clathrate type-I solid solution: Ba8PdxGe46−x−y y ( is a vacancy). The solid solution derives from binary clathrate Ba8Ge43 3 with a solubility limit of 3.8 Pd atoms per formula unit at T=800 °C. Structural investigations throughout the homogeneity region confirm cubic primitive symmetry consistent with the space group type Pmn and lattice parameters ranging from a=1.0657(2) nm for Ba8Ge433 to a=1.077 41(2) nm for Ba8Pd3.8Ge42.2 0.0. The primary field of clathrate crystallization has been elucidated from micrography and differential thermal analyses. Both heat capacity and inelastic neutron diffraction define a low-lying, almost localized, phonon branch. Studies of transport properties evidence electrons as the majority charge carriers for most of the homogeneity region; however, at the Pd-rich limit, holes dominate the electronic transport. The crossover between both regimes provides appropriate conditions for attractively high Seebeck values. The lattice contribution dominates the overall thermal conductivity.
en
Research Areas:
Metallic Materials: 60% Special and Engineering Materials: 40%