title: Magnesium-zinc ferrite nanoparticles: effect of copper doping on the structural, electrical and magnetic properties.
abstract: In this paper, Mg0.5Zn0.5-Cu(x)Fe2O4 ferrites nanoparticles were synthesized by facile co-precipitation route and characterized in detail in terms of their structural, electrical and magnetic properties as a function of Cu concentration. The prepared samples have cubic spinel phase as confirmed by X-ray diffraction patterns. The decrease of the lattice constant and increase of X-ray density indicate the solubility of Cu ions in the spinel lattice. The AC conductivity measurements between 300 K and 773 K at different frequencies 1 KHz up to 1 MHz, showed two different behaviors as semiconductor-like at high temperature and frequency depending behavior associated with dispersion phenomena at low temperatures. The conduction mechanism in the system is influenced by Cu concentration and the dominant one is the hopping conduction mechanism. Dielectric measurements at the same conditions of temperatures and frequencies exhibited that the dielectric loss increases with increasing the temperature and decreasing the frequency indicating the semiconducting nature of the ferrite compounds. An anomalous behavior of the dielectric loss is observed in samples with high Cu content which explained in terms of resonance between frequency accompanied the electronic hopping and the frequency of the external electric field. The analysis of Mössbauer spectra revealed that copper free compound is super-paramagnetically relaxed in nature and zinc free compound demonstrates ferrimagnetic order. Moreover, hyperfine field spectrum shows the migration of Cu ions from octahedral to tetrahedral site in zinc free compound.
authors.affiliation: Faculty of Science, Department of Physics, Zagazig University, Zagazig 44519, Egypt.
authors.forename: H M
authors.initials: HM
authors.lastname: Zaki
authors.forename: S
authors.initials: S
authors.lastname: Al-Heniti
authors.forename: Ahmad
authors.initials: A
authors.lastname: Umar
authors.forename: F
authors.initials: F
authors.lastname: Al-Marzouki
authors.forename: A
authors.initials: A
authors.lastname: Abdel-Daiem
authors.forename: T A
authors.initials: TA
authors.lastname: Elmosalami
authors.forename: H A
authors.initials: HA
authors.lastname: Dawoud
authors.forename: F S
authors.initials: FS
authors.lastname: Al-Hazmi
authors.forename: S S
authors.initials: SS
authors.lastname: Ata-Allah