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Phase-pure Aurivillius Bi5Ti3FeO15 nanoparticles were successfully prepared using a sol–gel method. Behaviours of crystallisation were characterised by XRD, DTA, FT-IR, Raman spectra and HRTEM. Mass spectrum was used to monitor the combustion products of all organics in the xerogel during calcination. An intermediate product, Bi2O2CO3, which blocks the generation of the pyrochlore phases, was confirmed by XRD patterns and IR spectra. Calculated by XRD data using the Debye–Scherrer method, the average grain size in powders calcinated at 500 °C was 17.7 nm and grew to 80.5 nm at 850 °C. The local symmetry connected to FeO6 octahedral was broken. The XRD refinement and XPS analyses inferred the valence increase of ferric ions. The maximum magnetisation of nanoparticles prepared at 850 °C was 4.2 emu/g. The field cooling (FC) and zero field cooling (ZFC) tests showed a wide range of the blocking temperature (T B) around 8–45 K answering for the lack of hump corresponding to the transition from superparamagnetism to blocking state.

The ternary Ag0.405Sb0.532Te alloy was prepared by spark plasma sintering, and its transport properties involving Seebeck coefficients, electrical and thermal conductivities were evaluated. The results reveal that the electrical conductivity mildly decreases from 7.6×104 S·m−1 to 6.6×104 S·m−1 when the temperature increases from 316 K, to 548 K. Above 438 K, the thermal conductivity gradually increases with the increase of the temperature, and below 438 K, a relative stable value of about 0.86 W·K−1·m−1 is obtained. The maximum thermoelectric figure of merit ZT is up to 0.65 at 548 K, a little higher than 0.61 of the ternary alloy Ag0.365Sb0.558Te. The thermoelectric properties have been improvement compared with the Ag-doped AgxBi0.5Sb1.5-xTe3 alloys (x=0-0.4). The action mechanism of the second phase Ag-Sb-Te ternary alloy precipitated in the AgxBi0.5Sb1.5-xTe3 alloys has been re-discussed.