Dresden 2014 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

DS: Fachverband Dünne Schichten

DS 42: Thermoelectric Materials

DS 42.13: Talk

Thursday, April 3, 2014, 18:15–18:30, CHE 89

Reduced thermal conductivity in Half-Heusler superlattices — •Paulina Holuj¹, Tino Jaeger¹, Benjamin Balke², Sascha Populoh³, Anke Weidenkaff³, Claudia Felser², and Gerhard Jakob¹ — ¹Institute of Physics, University of Mainz, Germany — ²Institute of Inorganic and Analytical Chemistry, University of Mainz, Germany — ³EMPA, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland

Research on thermoelectric materials has strongly increased in recent years due to their high application potential in production of a clean energy from wasted heat. Despite many advantages, their weakness is the limited efficiency, that is related to the dimensionless figure of merit ZT=α²σκ⁻¹T. One of the approaches to enhance ZT is the reduction of the thermal conductivity by phonon scattering at the interfaces of a superlattice (SL), keeping electrical parameters (α²σ) unchanged.

The ability to produce good quality SLs made out of Half-Heusler compounds is demonstrated by a clearly visible satellite peaks in X-ray diffractograms. Additionally, measured data are in good agreement with simulated patterns. Expected reduction of the thermal conductivity of TiNiSn/Zr_0.5Hf_0.5NiSn SLs has been obtained by the differential 3ω method. High temperature measurements of the Seebeck coefficient show a reversible behavior up to 550 K, revealing the stability of SLs up to this temperature range.

Currently HfNiSn, another member of the family of Half-Heusler materials is under investigation, where the ratio of interface scattering to atomic disorder scattering is enhanced.