Study of the dielectric behavior of Co–Ni–Li nanoferrites

• Published in: Journal of magnetism and magnetic materials Vol. 350; pp. 12 - 18
• Main Authors: Assar, S.T., Abosheiasha, H.F., El Nimr, M.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric loss; Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectric property; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electric stiffness; Electrical modulus; Exact sciences and technology; Ferrite; Grain boundaries; High strength steels; Hopping (conductivity); Nanoparticle; Nanostructure; Nickel; Permittivity (dielectric function); Physics; S parameters; Ferrite; Nanoparticle; Dielectric property; Electrical modulus; Electric stiffness; Grain boundaries; Electrical conductivity; Charge carriers; Dielectric relaxation; Ferrites; Nanoparticles; Complex impedance; Dielectric losses; Chemical composition; Stiffness; Permittivity
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2013.09.022

The ac conductivity and dielectric properties of Co0.5Ni0.5−2xLixFe2+xO4 nanoparticle ferrite samples (from x=0.00 to 0.25 in step of 0.05) synthesized by the citrate precursor method were studied by using a complex impedance technique. The effect of varying the frequency, temperature and composition on ac conductivity, dielectric constant and dielectric losses was discussed and justified in terms of hopping of charge carriers between Fe+3 and Fe+2 ions, Ni+2 and Ni+3 ions and Co+2 and Co+3 ions. The obtained results of the variation of S parameter with temperature show that the classical barrier hopping model is the most probable mechanism in the samples under investigation. While the results of the Cole–Cole diagrams of M″ vs. M′ at different temperatures ensure the presence of grain and grain boundaries having different but comparable conductivities in the investigated nanoparticle samples and also indicate that the studied ferrites exhibit the so called “electric stiffness”. •Dielectric properties of Co–Ni–Li ferrites had been studied by using a complex impedance technique.•Adding Li ions to the Co–Ni nanoferrites improves their dielectric properties.•The non-Debye type of dielectric relaxation prevails in the prepared nanosamples.•The classical barrier hopping model is the most probable mechanism for the prepared samples.•The diagrams of M″ vs. M′ indicate that the dominant property in the samples is electric stiffness.