Investigation on impedance spectroscopy and transport properties of co-doped bismuth ferrite ceramics

Yttrium (Y) and cobalt (Co) co-doped bismuth ferrite (BFO) nanopowders were synthesized by the sol-gel method. The purity of the phase of the samples was confirmed by the X-ray diffraction technique. Both grains and grain boundaries contribute to the electrical response of the samples. The modulus studies show that the charge carriers can perform both long- and short-range mobility. Meanwhile, the Nyquist plot analysis confirms the samples' non-Debye-type relaxation behaviour and negative temperature coefficient resistance nature. The frequency-dependent AC conductivity obeys the power law A omega s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A\omega<^>{s}$$\end{document} at a higher frequency. AC conductivity increases from 1.300 x 10-5 to 8.463 x 10-4 S m-1, increasing Y and Co contents in the BFO sample. The temperature dependence of the AC conductivity suggests the presence of different conduction processes for all the samples.