Structural and magnetic properties of Li–Cu mixed spinel ferrites

• Published in: Physica. B, Condensed matter Condensed matter, 2011-04, Vol.406 (9), p.1799-1804
• Main Authors: Manjura Hoque, S., Samir Ullah, M., Khan, F.A., Hakim, M.A., Saha, D.K.
• Format: Article
• Language: English
• Subjects: Coercivity; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Copper; Copper ferrite; Curie temperature; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; Ferrites; Lattice parameter; Lithium ferrites; Magnetic properties and materials; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Permeability; Physics; Sintering; Temperature dependence; X-rays
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2011.02.031

Li0.5−x/2CuxFe2.5−x/2O4 (where x=0.0–1.0) ferrites have been prepared by solid-state reaction. X-ray diffraction was used to study the structure of the above investigated ferrites at various sintering temperatures. Samples were sintered at 1000, 1100 and 1200°C for 3h in the atmosphere. For the sintering temperature of 1000°C, Li0.5−x/2CuxFe2.5−x/2O4 undergoes cubic to tetragonal transformation for higher Cu content. However, for the sintering temperature of 1100 and 1200°C, X-ray diffraction patterns are mainly characterized by fcc structure, though presence of tetragonal distortion was found by other temperature dependence of initial permeability curves. The lattice parameter, X-ray density and bulk density were calculated for different compositions. Curie temperature was measured from the temperature dependence of initial permeability curves. Curie temperatures of Li–Cu mixed ferrites were found to decrease with the increase in Cu2+ content due to the reduction of A–B interaction. As mentioned earlier, temperature dependence of initial permeability curves was characterized by tetragonal deformation for the samples containing higher at% of Cu. The complex initial permeability has been studied for different samples. The B–H loops were measured at constant frequency, f=1200Hz, at room temperature (298K). Coercivity and hysteresis loss were estimated for different Cu contents.