The Effect of Nano-SiO2 on the Structural, Electrical and Magnetic Properties of SiO2-LiFe5O8 Glass–ceramics Prepared by Sol Gel Auto-combustion Processing

Abstract

The glass–ceramic with the composition x(LiFe5O8)/(100 – x) SiO2 (x = 20, 30, 40, 50, 100 wt. % ) were prepared by sol gel auto-combustion method. The influence of the SiO2 ratio in the glass-ceramics strucure prepared was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Crystalline phases (LiFe5O8, SiO2, Fe2O3) were observed by X-ray powder diffraction in the glasses annealed at 800°C for 2h. The crystallite size was found to increase from 27.29 nm (x = 20%) to 91.48 nm(x = 100 %). The microstructure of the formed powders was SiO2 ratio dependent. Increasing the SiO2 ratio was found to inhibit the grain growth of the formed ferrite. The electrical conductivity of glass-ceramics samples were raised with increasing the concentration of SiO2 ratio as the result of increasing the hopping of electrons between Fe2+ and Fe3+ ions. The magnetic characteristics of the prepared glass ceramics were performed using a vibrating sample magnetometer in function of the magnetic field. The samples heat -treated at 800°C for 2h present a ferrimagnetic behavior. Alongside, the formed crystalline silicate lithium ferrite had good magnetic properties. High saturation magnetization (51.9 emu/g) was attained the formed ferrite sample of x = 100 % ratio annealed at 800°C for 2h.