Controlling the composition, microstructure, electrical and magnetic properties of LiFe5O8 powders synthesized by sol gel auto-combustion method using urea as a fuel

• Published in: Journal of magnetism and magnetic materials Vol. 374; pp. 495 - 501
• Main Authors: Rashad, M.M., El-Shaarawy, M.G., Shash, N.M., Maklad, M.H., Afifi, F.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2015
• Subjects: Combustion synthesis; Electrical property; Magnetic property; Microstructure; Spinel ferrite; Magnetic property; Combustion synthesis; Electrical property; Microstructure; Spinel ferrite
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2014.08.090

Nanocrystalline lithium ferrite LiFe5O8 powders were synthesized by the sol gel auto-combustion method from the corresponding metal nitrates using urea as a fuel. DTA results showed that the LiFe5O8 phase started to form at temperature around 385°C. X-ray diffraction analysis indicates that all compositions were formed in a single-phase cubic spinel structure at different annealing temperatures from 400 to 800°C for 2h. The lattice parameter was found to decrease whereas the particle size was increased with annealing temperature. The frequency exponent “s” of lithium ferrite lies in the range 0.5≤s≤1, which confirmed the electron hopping between Fe2+ and Fe3+ ions. The electron mobility in LiFe5O8 samples ranged from 0.05 to 0.29eV, which clearly indicated that the present lithium ferrites have semiconductor-like behavior. The saturation magnetization was increased on increasing the annealing temperature up to 800°C. High saturation magnetization (Ms=51.9emu/g) was achieved for the ferrite powders produced at annealing temperature 800°C for 2h.
•LiFe5O8 phase was prepared at low temperature 400°C.•Microstructure was temperature dependent.•Electron mobility ranged from 0.05 to 0.29eV.•Frequency exponent “s” lies in the range 0.5≤s≤1•Good magnetization was achieved.