Investigation of the structural, surface topographical, fractal, capacitive, and electrical properties of a defect brownmillerite perovskite material KBiFeMnO5 for electronic devices

Abstract

This article reports the development and characterizations (structural, surface topographical, fractal, dielectric, transport, impedance, resistive, and current–voltage properties) of a defect brownmillerite material KBiFeMnO₅. Preliminary investigation of the X-ray diffraction (XRD) pattern with the Monte Carlo technique with McMaille 4.0 shows monoclinic symmetry having lattice parameters: a = 8.261 Å, b = 8.251 Å, c = 7.524 Å, and β = 108.58°. The analysis of the Williamson–Hall plot illustrates the average crystallite size and micro-lattice strain are 124.6 nm and 0.002, respectively. The scanning electron microscopic image examines the microstructural surface topography, fractal analysis, and surface roughness (using the standard of ISO25178) of the material. Maxwell–Wagner dielectric dispersion, relaxation, and transport mechanisms are investigated utilizing dielectric, impedance, and conductivity spectra accumulated within the experimental frequency (1 kHz to 1 MHz) and temperature (25–500 °C) ranges. The energy band of an intrinsic region with a 1 MHz frequency indicates the semiconducting behavior of the material. The logarithmic current density and electric field are used to investigate the presence of ohmic and space charge limited conduction (SCLC) mechanisms. The thermistor constant (β) is determined to be 4633.86, and the temperature coefficient of resistance (TCR) is −0.00322, which may be suitable for high-temperature NTC thermistors and other related device applications.