Dielectric behavior, Complex modulus, and conduction mechanism studies of Ni-doped La2SrFe2-xNixTiO9 triple perovskite for high-frequency electronic applications

In this study, we have examined the dielectric, a.c conductivity, and complex modulus studies of Ni-doped triple perovskite La₂SrFe_2-xNi_xTiO₉ at low temperatures prepared by using the solid-state reaction route method. The XRD analysis shows that the material possesses the orthorhombic structure with space group Pnma. The observed enhancement of the dielectric constant with temperature and its reduction with frequency can be revealed by applying the Maxwell–Wagner relaxation model. The dielectric loss study shows that the material possesses the Arhenious relaxation behavior. From the Arrhenius equation, we have found the activation energy of the material whose values are nearly close to each other. From the impedance spectroscopy studies, we have observed that the material possesses the contribution of both the grains and the grain boundaries, where grains are observed at lower frequencies and the grain boundaries are at higher frequencies. Our observations reveal that all modulus curves converge at low temperatures, demonstrating a similar relaxation pattern, while the curves at high temperatures display a dispersed behavior beyond the peak frequency. The observed AC conductivity adheres to Jonscher’s power law, suggesting that the synthesized material exhibits semiconducting characteristics. Additionally, the temperature-dependent components indicate that the material aligns with the non-overlapping polaron hopping and carrier barrier hopping models, which are the most suitable frameworks for elucidating the conduction mechanism of the samples. The Non-overlapping Tunneling Model (NSPTmodel) has facilitated calculating hopping energy, density of states, and hopping distance, enhancing its potential applications in high-frequency electronic and switching devices.