Transport and mechanical property evaluation of (AgSbTe)1−x(GeTe)x (x=0.80, 0.82, 0.85, 0.87, 0.90)

(AgSbTe2)1−x(GeTe)x (known collectively by the acronym of their constituent elements as TAGS-x, where x designates the mole fraction of GeTe) materials, despite being described over 40 years ago, have only recently been studied in greater detail from a fundamental standpoint. We have prepared a series of samples with composition (AgSbTe2)1−x(GeTe)x (x=0.80, 0.82, 0.85, 0.87 and 0.90). Cast ingots of the above compositions were ground and consolidated by spark plasma sintering (SPS). Sintering conditions, specifically high applied pressures of 65 MPa and slow heating rates, were identified as important variables that lead to samples with low porosity and good mechanical strength. The resulting ingots were cut for high temperature electrical, thermal transport and mechanical property evaluation. TAGS-85 was found to have the highest ZT of all samples investigated (ZT=1.36 at 700 K) as a result of its very low value of thermal conductivity. Hall effect measurements performed from 5 to 300 K found these materials to have complex multi-band transport characteristics.

Grapical AbstractPowder X-ray diffraction of TAGS-x (x=0.80, 0.82, 0.85, 0.87 and 0.90) showing characteristic bifurcation indicative of rhombohedral structure.Figure optionsDownload full-size imageDownload as PowerPoint slide