Conduction mechanism and dielectric relaxation in LiMg0.5Fe2O4 spinel ferrite: A temperature- and frequency-dependent complex impedance study

Abstract

The development of multifunctional materials represents a leading area of research, aiming to enhance material versatility for a wide range of applications. Ferrite materials have garnered important interest due to their exceptional properties. In this study, LiMg₀.₅Fe₂O₄ was synthesized by solid-state reaction with sintering at 1100 °C. X-ray powder diffraction confirmed the formation of a single cubic spinel phase with the Fd $\bar{3}$ m space group. The scanning electron microscopy revealed a grain size of approximately 2.27 μm. Impedance spectroscopy was conducted over a temperature range of 300 K–390 K and a frequency range of 10²Hz–10⁶ Hz. The Nyquist plot highlighted the contributions of grain, grain boundary, and electrode effects across a studied temperature range. AC conductivity follows the Jonscher law and conduction mechanisms governed by the correlated barrier hopping and non-overlapping small-polaron tunneling models. Furthermore, the temperature coefficient of resistivity suggests that LiMg₀.₅Fe₂O₄ is a promising candidate for optoelectronic devices, infrared radiation detection, and bolometric applications.