Structural, thermodynamic, electrical and dielectric properties of SrZnP2O7 diphosphates compared to SrAII P2O7 (A = Sr and Ni) with analysis of OLPT conduction mechanism
Abstract
A polycrystalline sample of SrZnP2O7 was successfully synthesized via the conventional solid-state reaction method. Its structural and vibrational properties were characterized using X-ray powder diffraction (XRD) and infrared (IR) spectroscopy, while its electrical and dielectric properties were investigated through impedance spectroscopy. XRD analysis confirmed the formation of a single-phase compound crystallizing in the monoclinic system with space group P21/n. The IR spectrum revealed all the expected vibrational modes associated with the P2O7 polyhedral units. Electrical conductivity measurements, carried out over a frequency range of 209 Hz to 1 MHz and a temperature range of 550 K to 711 K, were used to analyze the conduction mechanism. The temperature dependence of the frequency exponent āsā indicated that the conduction in SrZnP2O7 follows the overlapping large polaron tunneling (OLPT) model. A strong correlation between the material's structure and its electrical performance was established. Furthermore, comparative analysis with previously reported compounds, Sr2P2O7 and SrNiP2O7, demonstrated that SrZnP2O7 exhibits superior ionic conductivity, highlighting its promising potential for applications in solid-state ionic devices.