Effect of sintering temperature and the particle size on the structural and magnetic properties of nanocrystalline Li0.5Fe2.5O4

• Published in: Journal of magnetism and magnetic materials 2011-12, Vol.323 (23), p.3104-3108
• Main Authors: Shirsath, Sagar E., Kadam, R.H., Gaikwad, Anil S., Ghasemi, Ali, Morisako, Akimitsu
• Format: Article
• Language: English
• Subjects: Blocking temperature; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Li0.5Fe2.5O4; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetization; Particle size; Permittivity (dielectric function); Physics; Sintering temperature
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2011.06.065

Sintering temperature and particle size dependent structural and magnetic properties of lithium ferrite (Li0.5Fe2.5O4) were synthesized and sintered at four different temperatures ranging from 875 to 1475K in the step of 200K. The sample sintered at 875K was also treated for four different sintering times ranging from 4 to 16h. Samples sintered at 1475K have the cubic spinel structure with a small amount of α-Fe2O3 (hematite) and γ-Fe2O3 (maghemite). The samples sintered at≤1275K do not show hematite and maghemite phases and the crystals form the single phase spinel structure with the cation ordering on octahedral sites. Particle size of lithium ferrite is in the range of 13–45nm, and is depend on the sintering temperature and sintering time. The saturation magnetization increased from 45 to 76emu/g and coercivity decreases from 151 to 139Oe with an increase in particle size. Magnetization temperature curve recorded in ZFC and FC modes in an external magnetic field of 100Oe. Typical blocking effects are observed below about 244K. The dielectric constant increases with an increase in sintering temperature and particle size. ► Lithium ferrite with heat treatment. ► Structure changes from disordered system to ordered system. ► Magnetization increases with sintering temperature. ► Blocking temperature increases with sintering temperature. ► Coercivity decreases with sintering temperature.