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Zusammenfassung:
A systematic investigation on tuning the charge carrier concentration by
substitution of the Ru position in RuIn3 is performed. Samples with
nominal composition Ru0.95T0.05In3 (T = Re, Rh, Ir) were synthesized via
liquid-solid-reaction and subsequent spark plasma sintering treatment.
The chemical composition was characterized by X-ray, metallographic and
microstructure analysis revealing solid solutions in the samples with Rh
and Ir, whereas Re cannot be incorporated in RuIn3. Minor oxide
impurities in the commercially available starting elements, the
homogeneity range of RuIn3 and the redox potentials of the participating
elements are the key for interpreting the observed lattice parameters
and the corresponding composition. Both, substitutions with Rh or Ir and
Re inclusions in RuIn3 lead independently to a significant decrease of
the total thermal conductivity down to approximately one half of the
value observed for binary RuIn3, prepared with commercially available
starting materials. The electrical resistivity was reduced by
substitution and the temperature dependence changes from
semiconductor-like, for RuIn3, to metal-like in the substitution
derivatives. At the same time the sign change in the thermopower at high
temperatures, characteristic for binary RuIn3, is suppressed, attaining
only electrons as majority carriers. (C) 2014 Elsevier Inc. All rights
reserved.
