A comprehensive study of structural, dielectric, electrical, thermal, and optical properties of Na/W co-doped BiMnO3 complex electroceramic; (Bi1/2Na1/2)(Mn1/2W1/2)O3

Abstract

In this report, we present the fabrication through the solid-state method and subsequent characterization (structural, electrical, optical, and thermal properties) of a lead-free Na/W modified complex BiMnO₃ ceramic of a chemical composition (Bi_1/2Na_1/2)(Mn_1/2W_1/2)O₃. The structural analysis, including the determination of structure and lattice parameters, was performed using X-ray diffraction data, revealing a monoclinic crystal structure of the material. Additional insights into its vibrational properties were obtained through Raman spectroscopy and Fourier Transform Infrared spectrum. The electronic behaviour of the prepared sample was investigated using photoluminescence (PL). Scanning electron microscope analysis revealed a uniform distribution of grains. The energy-dispersive X-ray study confirmed compositional uniformity. Furthermore, a comprehensive analysis of dielectric properties, impedance, modulus, and conductivity was carried out over a range of frequencies (1 kHz – 1 MHz) and temperatures (25 °C – 500 °C) to understand the Maxwell–Wagner type of dielectric dispersion, relaxation, and transport mechanisms. The Nyquist plots and the temperature-dependent conductivity data exhibited a negative temperature coefficient of resistance behavior. The modulus data indicated a scaling nature, indicative of non-Debye type relaxation. Additionally, the study of polarization with an electric field suggested the possibility of a ferroelectric behavior of the material.