Structural, characterization and electrical properties of AgPbmSbTem+2 compounds synthesized through a solid-state microwave technique

• Synthesized the quaternary alloys AgPbmSbTem+2 by solid state microwave at 1173 to 1183 K for 25 min.
• The behavior of m-value with increased lattice constant of the powder.
• The value of the S is –419.69 μVK−1 for AgPb8SbTe10 at 338 K.
• The value of S2σ for AgPb8SbTe10 sample reaches 1.87 mW K−2 m−1 at 310 K.

AgPbmSbTe2+m compounds are prepared through solid-state microwave synthesis method with different elements ratio of m (0.0 ≤ m ≤ 10). The X-ray diffraction method confirmed that all of the synthesized samples are polycrystalline with a rock salt NaCl-type crystalline structure. The lattice constant of the prepared AgPbmSbTe2+m increases from 6.089 Å to 6.467 Å with the increase in the mole fraction (m) from 0.0 to 10, respectively. Scanning electron microscopy images showed that increasing the mole fraction allows the continuous growth of multigrains, and volume of these grains increased with m value. The electrical conductivity (σ) measurements of AgPbmSbTe2+m prepared with a different m ratio exhibited a degenerate semiconductor behavior for all samples, and the sample prepared with m = 0 showed a higher σ of 482.96 S/cm at 300 K compared by the others. All of the samples had a negative Seebeck coefficient (S), indicating that the AgPbmSbTe2+m compounds are of n-type conductivity. Moreover, the maximum value of S is −419.69 μV/K at 338 K that obtained for the sample prepared with m = 8 while the minimum value of S was ˗6.8 μV/K recorded when the composition ratio of 4.