TRANSPORT-PROPERTIES OF RUSI, RUGE, OSSI, AND QUASI-BINARY ALLOYS OF THESE COMPOUNDS

RuSi, RuGe, OsSi and the solid solutions RuSi0.5Ge0.5 and Ru0.5Os0.5Si are investigated. All of them crystallize in the cubic B20 structure. The systems RuSi-RuGe and RuSi-OsSi form solid solutions which obey V egard's law. RuSi, RuSi0.5Ge0.5, and RuGe are semiconductors with band gaps of 0.26, 0.20 and 0.15 eV, respectively. OsSi and Ru0.5Os0.5Si a re degenerate semiconductors; their band gaps are larger than 0.26 eV. The thermal conductivity of the materials is dominated by the contrib utions of the lattice. The magnetic behavior is temperature independen t and diamagnetic. RuSi and RuSi0.5Ge0.5 exhibit large Seebeck coeffic ients of almost 300 mu V K-1, but their dimensionless thermoelectric f igure of merit ZT does not exceed 0.03. (C) 1998 Elsevier Science S.A. All rights reserved.