Cerium modified (BiFeO3)0.5 – (MgTiO3)0.5 ceramics: Structural, microstructural, dielectric, transport and optical properties

Abstract

In this communication, the synthesis (solid-state reaction) and characterization (structural, dielectric, and optical) of the 0.5BiFeO3-0.5MgTi1-xCexO3 (x = 0, 0.03. 0.06 and 0.1), (BFMTO) ceramics are reported. The x-ray diffraction (XRD) analysis confirms the formation of orthorhombic crystal symmetry (#Cmm2) and is well-supported by the results of the tolerance factor. The average crystallite size is about 30 nm. The ratio of average grain size to average crystallite size may be one of the reasons for better dielectric properties in the prepared samples. The microstructural analysis by scanning electron microscopy (SEM) micrograph suggests the presence of uniformly distributed grains through well-defined grain boundaries. The compositional and purity of the samples were studied by energy dispersive x-ray analysis (EDX). The study of the Fourier transform infrared spectroscopy (FTIR) spectrum reveals the presence of all functional groups related to constituent elements in the samples. The analysis of the dielectric properties suggests the presence of the Maxwell-Winger type of dispersion. The study of impedance spectroscopy suggests the fact that how the grains and grain boundaries play an important role in defining the conductivity mechanism and hence prove a non-Debye type of relaxation. The presence of semicircular arcs for x = 0, 0.03, 0.06, and 0.1 ceramics in both Nyquist and Cole-Cole plots reveal a negative temperature coefficient of resistance (NTCR) character. The study of UV visible spectra predicts an energy bandgap in the range of 1.24 to 1.62 eV, which makes the compound a suitable candidate for photovoltaic applications.