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A3: High temperature materials

Manipulating Thermal Conduction in Bulk Polycrystalline SrTiO3-δ Ceramics via Nonstoichiometry Tuning

Arash Mehdizadeh Dehkordi1, Sriparna Bhattacharya2, Husam N. Alshareef3 and Terry M. Tritt1,2
1 Dept. of Mater. Sci. and Eng., Clemson University2 Dept. of Phys. and Astronomy, Clemson University3 Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST)

Large thermal conductivity (~ 12 Wm-1K-1 at 300K) in SrTiO3 detrimentally affects the thermoelectric performance of these oxide materials. Due to the inherent small phonon mean free path in strontium titanate, nanostructuing techniques are not viable options for the improvement of thermoelectric properties through the reduction of the lattice thermal conductivity. In this study, we experimentally investigate the composition-structure-property relationship in these polycrystalline ceramics with a focus on the thermal properties. A significant reduction in thermal conductivity (~ 40% at room temperature) was achieved for nonstoichiometric SrTiO3 versus reported for pristine single crystal counterpart.  Samples were synthesized using a combined solid-state reaction and spark plasma sintering (SPS) technique in order to achieve high density polycrystalline bulk materials. The results of thermal transport measurements will be presented and discussed over a wide temperature range. These results could provide a guideline for manipulating thermal properties of SrTiO3 in order to further improve thermoelectric performance of these oxide ceramics.

 

This collaborative research was funded by the competitive Faculty Initiated Collaboration (FIC) grant from KAUST.