Crystallographic modeling and impedance studies of gadolinium modified La1−xGdxMnO3 (x = 0.1–0.3) ceramics

Abstract The crystal chemistry of perovskite structured ceramic phases: La 0.9 Gd 0.1 MnO 3 (LMGd-1), La 0.8 Gd 0.2 MnO 3 (LMGd-2) and La 0.7 Gd 0.3 MnO 3 (LMGd-3) have been investigated using General Structure Analysis System (GSAS) programming. The LMGd phases crystallize in the space group R -3 c and Z  = 6. Powder diffraction data have been subjected to Rietveld refinement to arrive at a satisfactory structural convergence of Rietveld parameters: R p , R wp and goodness of fit. Lattice parameters, bond lengths and bond angles have been calculated from GSAS software. Their electrical behaviour investigated by impedance spectroscopy in the frequency range 42 Hz–5 MHz at temperatures between 50 ° and 300 °C. Nyquist plots show the dominance of grain contribution and Debye – like relaxation in the materials. Conductivity data as a function of temperature and frequency suggest semiconductor behavior of the materials.