Structural, AC conductivity, dielectric behavior and magnetic properties of Mg-substituted LiFe sub(5)O sub(8) powders synthesized by sol-gel auto-combustion method

• Published in: Journal of materials science. Materials in electronics 2015-08, Vol.26 (8), p.6040-6050
• Main Authors: El-Shaarawy, M G, Rashad, M M, Shash, N M, Maklad, M H, Afifi, F A
• Format: Article
• Language: English
• Subjects: Alternating current; Annealing; Electric fields; Ferrite; Lithium ferrite; Magnesium; Magnetic properties; Sol gel process
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-015-3181-2

Magnesium-substituted lithium ferrite powders (Li sub(1-x)Mg sub(2x)Fe sub(5-x)O sub(8) where x = 0.0-0.8) were prepared by sol-gel auto-combustion method. XRD profiles revealed that all compositions were single cubic ferrite structure for the precursors annealed at 800 degree C for 2 h. The crystallite size was found to decrease whereas the lattice parameter was increased with increasing Mg super(2+) ion content. The microstructure of the formed powders was Mg concentration dependent. Increasing the Mg super(2+) ion ratio was found to inhibit the grain growth of the formed ferrite. The AC electrical conductivity of Mg super(2+) ion substituted lithium ferrite samples was raised with increasing the concentration of Mg super(2+) ions as the result of increasing the hopping of electrons between Fe super(2+) and Fe super(3+) ions. Meanwhile, dielectric constant ( epsilon ') was diminished with increasing the frequency of external electric field as well as increasing the temperature and concentration of Mg super(2+) ions. Alongside, the formed crystalline magnesium substituted lithium ferrite had good magnetic properties. High saturation magnetization (78.7 emu/g) was attained by the formed ferrite sample at Mg super(2+) molar ratio of 0.4 annealed at 800 degree C for 2 h.