Effective thetnial conductivity of SrBi4Ti4O15-La0.7Sr0.3Mn0.3 oxide composite: Role of particle size and interface thermal resistance

We present a novel approach to reduce the thermal conductivity (k) in thermoelectric composite materials using acoustic impedance mismatch and the Debye model, Also, the correlation between interface thermal resistance (R-int) and the particle size of the dispersed phase on the k of the composite is discussed. In particular, the k of an oxide composite, which consists of a natural superlattice Aurivillius phase (SrBi4Ti4O15) as a matrix and pemvskite (La0.7Sr0.3MnO3) as a dispersed phase, is investigated. A significant reduction ink of composite, even lower than the k of the matrix when the particle size of La0.7Sr0.3MnO3 is smaller than the Kapitza radius (a(k)) is observed, depicting that R-int dominates for particle size lower than a(k) due to increased surface to volume ratio. The obtained results have the potential to provide new directions for engineering composite thermoelectric systems with desired thermal conductivity and promising in the field of energy harvesting.

Automated summary

This study presents a novel approach to reduce thermal conductivity in thermoelectric composite materials using acoustic impedance mismatch and the Debye model, and investigates the correlation between interface thermal resistance and particle size on the thermal conductivity of the composite. Experimental results show a significant reduction in thermal conductivity of the composite when the particle size of the dispersed phase is smaller than a certain value, providing new directions for engineering composite thermoelectric systems with desired thermal conductivity.