Room temperature crystal structure and low temperature scaling behavior of 0.70BiFeO3-0.30Sr(Fe0.5Nb0.5)O3 ceramic

Abstract

The frequency-dependent dielectric relaxation of ferroelectric BiFeO3-0.30Sr(Feo.5Nb0.5)O3 (BF-0.30SFN) ceramic, synthesized by solid-state reaction route is studied in the temperature range from 2 K to 300 K by ac-impedance spectroscopy. The x-ray diffraction profile of the powder sample of 0.70BF-0.30SFN at room temperature exhibits coexistence of two phases. The first phase is monoclinic in Cc space group and the second is cubic in Pm-3m space group. The ionic polarization calculated from structural data is found to be ~ 29.297µ.C/cm2. The activation energy calculated from the frequency dependence of imaginary part of electric modulus spectra is found to be 0.415eV, which suggests that the bulk conduction in BF-0.30SFN is due to polaron hopping based on the electron carriers. The scaling behavior of the imaginary part of the electric modulus (M") suggests that the relaxation describes the same mechanism at various temperatures. The SEM microstructure of this ceramic show the grain size lies in the range 3um to lOum and EDS spectra reveals the good chemical homogeneity of the ceramic sample. © 2019 American Institute of Physics Inc.. All rights reserved.