Synthesis, morphology investigation and electrical conduction mechanism of rubidium yttrium diphosphate

Abstract

The rubidium yttrium diphosphate compoundwas synthesized by solid route. The characteristics of this compound have been determined using X-ray powder diffraction, morphological, Raman and complex impedance spectroscopy. While X-ray powder diffraction revealed that RbYP₂O₇ compound crystallizes in the monoclinic system (P2₁/c space group), the SEM mapping demonstrated that the particles have the shape of squares of different sizes and demonstrate that the mean crystalline size of the specimen is 1.75 μm. The complex impedance spectra analysis indicated that the electrical features of the compound are largely dependent on temperature and frequency. Two semi circles are detectable in the Nyquist plots of the complex impedance spectra, suggesting the contribution of the effects of the grain and grain boundary. Non-Debye type relaxation mechanism coupled with negative temperature coefficient of resistance (NTCR) behaviour was indicated by temperature dependent impedance spectroscopy. Additionally, the AC conductivity frequency dependence was interpreted in terms of Jonscher’s law, whereas DC conductivity promotes the polaron assisted hopping in RbYP₂O₇ composition having activation energies of the grain σ_g and grain boundary are Ea_g= 0.81 eV and Ea_gb = 1.21 eV, respectively. The power law exponent (s) yielded that the correlated barrier hopping (CBH) model corresponds to the dominant transport process in this material. Furthermore, the multiple relaxation process was revealed by the modulus spectroscopy dominated by the mixed Rb⁺ cation motion within the investigated material structure.