Microstructural and dielectric characteristics of the Ce-doped Bi\(_{2}\)FeMnO\(_{6}\)

Abstract

A double-perovskite material Bi2FeMn0.94Ce0.06O6 (BFMCO) was synthesized by solid state reaction technique and characterized it by various techniques (structural, microstructural, dielectric, impedance and modulus properties). The material has an orthorhombic crystal structure with an average crystallite size of 52.4 nm, as revealed by X-ray diffraction data (XRD). The scanning electron microscope (SEM) image shows the presence of nano rod-shaped grains and well-defined grain boundaries in this material, with an average grain size of 21.8 µm. The Energy dispersive X-ray (EDX) analysis and color mapping confirm the purity and the composition of the material. The dielectric, impedance and modulus properties are investigated in the temperature range of 25℃ to 500℃ and frequency range of 1 kHz to 1 MHz. The material exhibits a high dielectric constant at low frequency region and a low dielectric loss, which make it a suitable candidate for better energy storage devices. The impedance study reveals the negative temperature coefficient of resistance (NTCR) behavior of the material. The modulus study indicates the non-Debye relaxation of the material. The semi-conducting nature of the material is verified by the semi-circular arcs observed in both Nyquist and Cole-Cole plots. Thermally activated conduction mechanism is confirmed from ac conductivity study.