Crystal structure transition and multiferroic properties in Bi_(1-x)Ho_xFeO_3 (x = 0.05, 0.10, 0.15, 0.20) ceramic by rietveld analysis

摘要

Bi_(1-x)Ho_xFeO_3 multiferroics (with x = 0.05, 0.10, 0.15, & 0.20) were synthesized via conventional solid state reaction method. X-ray patterns recorded by powder diffraction method depicts change in crystal structure at concentration x = 0.20. Rietveld refinement of the XRD patterns deduce the stabilisation of rhombohedral R3c phase upto concentration x = 0.15, while for concentration x = 0.20, the mixed phase model including rhombohedral R3c and orthorhombic Pnma space group was established to give the best fitting. Dielectric behaviour of all prepared ceramic samples was carried by impedance / gain phase analyser within the frequency range from 100Hz to 7MHz at different temperatures. The electron density contours obtained by G-Fourier program of Fullprof suite deduced the smooth spread of diffracting elements throughout the refinement simulated crystal structure. The change in crystal structure is attributed to the distortion of FeO_6 octahedra via doping of Ho at phase boundaries.