Dresden 2014 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 35: Poster I: Application of thin films; Focus session: Sensoric micro and nano-systems; Focus Session: Sustainable photovoltaics with earth abundant materials; Graphen (joint session with TT; MA; HL; DY; O); Ion and electron beam induced processes; Layer properties: electrical, optical, and mechanical properties; Magnetic/organic interfaces, spins in organics and molecular magnetism; Micro- and nanopatterning (jointly with O); Organic electronics and photovoltaics (jointly with CPP, HL, O); Thermoelectric materials

DS 35.69: Poster

Mittwoch, 2. April 2014, 17:00–20:00, P1

Phase separation in the (Ti,Zr,Hf)CoSb_0.8Sn_0.2 system for improved thermoelectric properties — •Elisabeth Rausch¹, Benjamin Balke¹, and Claudia Felser^1,2 — ¹Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität Mainz — ²Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden

Heusler compounds with C1_b structure are very promising materials for high-temperature thermoelectric applications. Their advantages are excellent electronic properties reflected in high power factors and high mechanical stability. However, disadvantage is their relatively high thermal conductivity. To overcome this obstacle the fabrication process of state-of-the-art p-type materials based on the TiCoSb system all involve a nano structuration via ball-milling. We herein present an alternative approach for the improvement of the thermoelectric properties. The effect of an intrinsic phase separation caused by isoelectronic alloying of Ti with Zr and Hf was investigated in the system YCoSb_0.8Sn_0.2 (Y = Ti, Zr, Hf, Ti_0.5Hf_0.5, Zr_0.5Hf_0.5, Ti_0.5Hf_0.5, Ti_0.3Zr_0.35Hf_0.35). Upon this we achieved a thermal conductivity as low as 3.1 mW/K and a maximum figure of merit ZT of 0.9 at 979 K with a simple arc melting fabrication process.