The analysis of the structure, electrical, and dielectric properties of δ-MnO2 prepared through hydrothermal processes

In this work, the structure, electrical, and dielectric properties of nano size structured of MnO2 were studied. The preparation was carried out through hydrothermal processes of a mixture of KMnO4 solution, HNO3, and SiO2 at 180°C in various dwell times of reaction: 7, 9, and 20 hours. X-ray powder diffraction (XRD) patterns of all prepared samples were identified δ-MnO2 having nano-size particle. Micro-strain and dislocation inside the grains were also presented. The impedance complex analysis Z′ - Z″ plots were performed in the frequency range of 0.1 Hz-32 MHz and room temperature signing grains and grain boundaries resistance and capacitance electrical circuit network. The AC conductivity, and dielectric properties: relative permittivity, areal capacitance, losses (tan δ), were explored to analyzed structural variation related to sample preparation.