[Zurück]

N. Melnychenko-Koblyuk, A. Grytsiv, P. Rogl, E. Bauer, R. Lackner, E. Royanian, M. Rotter, G. Giester:
"Structure and Physical Properties of Clathrate I Systems Ba₈Pd_xSi_46-x and Ba₈Pt_xSi_46-x";
Journal of the Physical Society of Japan, 77 (2008), S. 54 - 60.

Phase relations at 900 °C, crystal chemistry, electrical and thermal transport measurements, and heat capacity data are reported for the clathrate systems: Ba₈{Pd,Pt}_xSi_46-x. For both systems a ternary clathrate phase was identified with a small homogeneity region extending at 900 °C for 2.5≤_xPd≤4.1 and 2.8≤_xPt≤4.9, respectively. Structural investigations of these clathrate phases at 300, 200 and 100 K define cubic primitive symmetry with the space group type Pm3n consistent with clathrate type I. Studies of electronic and thermal transport groups both series of compounds close-by a semiconducting state. An sizeable charge carrier concentration in these systems, however, prevents sufficiently large thermopower values. In comparison to isostructural type I clathrates based on Ge, thermal conductivity - dominated by the lattice contribution - is larger due to the smaller mass of Si.

clathrate type I structure, Ba₈Pd_xSi_46-x, Ba₈Pt_xSi_46-x, phase equilibria, XPD, XSCD, transport properties

http://jpsj.ipap.jp/link?JPSJS/77SA/54/