Structural characterization and dielectric behavior of substituted bismuth niobate Bi17Nb3-4xV2xP2xO33 with fluorite-like structure

Abstract

Structural, morphological, and dielectric properties of substituted bismuth niobates Bi17Nb3-4xV2xP2xO33 with a fluorite-like structure have been reported. The study focuses on substituting Nb5+ with V5+ and P5+ cations in Bi17Nb3O33. The resulting ceramics were synthesized using the solid-state reaction technique, and their crystal structure was analyzed using X-ray diffraction. The analysis confirmed the stabilization of the compounds in a single phase of a cubic fluorite structure. Structural refinement analysis has been performed for the compound Bi17Nb2.4V0.3P0.3O33 to investigate the details of the crystalline structure which was found to be a cubic fluorite structure at room temperature (space group Fm3‾m). Scanning Electron Microscopy (SEM) was used to examine the surface morphology of the samples, which exhibited irregular shapes and heterogeneous size distribution. The dielectric properties of the ceramics were analyzed, and the dielectric permittivity (ε’) and loss factor (tan δ) were measured at different frequencies and temperatures. The results showed anomalies in each frequency-dependent curve, indicating a relaxation phenomenon. The electrical conductivity (σ) of the ceramics was studied, and it was found that the conductivity displayed a frequency-independent plateau at low frequencies, indicating a semiconductor behavior. The complex impedance spectra and electrical modulus analysis were also conducted to investigate the relaxation processes in the material.