Journal of Electronic Materials

, Volume 45, Issue 3, pp 1382–1388 | Cite as

Miscibility Gap in the Phase Diagrams of Thermoelectric Half-Heusler Materials CoTi\(_{1-x}Y_x\)Sb (Y = Sc, V, Mn, Fe)

  • Joaquin Miranda MenaEmail author
  • Elisabeth Rausch
  • Siham Ouardi
  • Thomas Gruhn
  • Gerhard H. Fecher
  • Heiko G. Schoberth
  • Heike Emmerich
  • Claudia Felser


The half-Heusler system CoTi\({_{1-x}Y_x}\)Sb (Y = Sc, V, Mn, Fe) has been investigated by means of an ab initio-based mean-field model which provides phase diagrams of alloys. Co(Ti,Y)Sb materials show a miscibility gap, which leads to spontaneous demixing within a spinodal region. The results are compared with experimental investigations of microstructure and transport properties of the alloys. The thermoelectric properties of the solid solution were investigated comprehensively by measuring the temperature dependence of the Seebeck coefficient as well as electrical and thermal conductivity. Compared with pure CoTiSb, the thermal conductivity of substituted CoTi\({_{0.9}Y_{0.1}}\)Sb was significantly reduced by approximately 53% for Y = V. Here, we report on the effect of phase separation in the Co(Ti,Y)Sb system and its consequences for the thermoelectric figure or merit.


Thermoelectric materials transition-metal alloys and compounds atomic-scale structure Heusler compounds phase separation 


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The authors acknowledge financial support from the Deutsche Forschungsgemeinschaft (Program SPP 1386). We thank Sylvia Kostmann for specimen preparation, and Monika Eckert, Petra Scheppan, and Ulrich Burkhardt for SEM and EDX measurements.


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Copyright information

© The Minerals, Metals & Materials Society 2015

Authors and Affiliations

  • Joaquin Miranda Mena
    • 1
    Email author
  • Elisabeth Rausch
    • 2
  • Siham Ouardi
    • 2
  • Thomas Gruhn
    • 1
  • Gerhard H. Fecher
    • 2
  • Heiko G. Schoberth
    • 1
  • Heike Emmerich
    • 1
  • Claudia Felser
    • 2
  1. 1.Lehrstuhl für Material- und Prozesssimulation, Universität BayreuthBayreuthGermany
  2. 2.Max Planck Institute for Chemical Physics of SolidsDresdenGermany

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