Rietveld refinement of the semiconducting system Bi2−xFexTe3 from X-ray powder diffraction

The semiconducting system Bi_2−xFe_xTe₃ (x = 0.0, 0.02, 0.04 and 0.08) was synthesized at 1000 °C for 30 h. The scanning electron microscope (SEM) image reveals the tendency of the Bi_2−xFe_xTe₃ system to form a sheet structure with more pronounced alignment and to enhance the formation of some microstructure tubes. The structure of the system under study was refined on the basis of X-ray powder diffraction data using the Rietveld method. The analysis revealed the complete miscibility of Fe in the Bi₂Te₃ matrix and hence the formation of single phase. The system crystallizes in the space group R-3m 1 6 6]. The lattice parameters and the unit cell size slightly change by the incorporation of Fe. The refinement of instrumental and structural parameters led to reliable values for the R_B, R_F and Chi².