Dielectric and structural properties of SiO2-LiFe5O8 glass–ceramics prepared by sol–gel processing

The lithium ferrite (LiFe5O8) is a very interesting ferromagnetic material due to its square hysteresis loop and high Curie temperature. It has attracted the attention of scientists and engineers for a long time with regard to their application as a low-cost substitute of garnet ferrites in several devices. In this work we present the first studies of the (x)SiO2-(1−x)[Li2O.5Fe2O3] (% mol) glass and glass–ceramic, with x = 94 and x = 97%, prepared by the sol–gel method. The influence of the heat-treatment parameters, in the glass and glass–ceramics structure prepared was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy measurements. The increase of the volume ratio between the LiFe5O8 particles and the glass matrix leads to an increase of the conductivity. The dielectric measurements show that the crystalline growth orientation of the LiFe5O8 particles, embedded in the glass matrix, is random.