Preparation and electrical properties of Ni-Cu-Zn system doped with the magnesium oxide.

A sery of ferrite samples, Ni_0.1Cu_0.2Mg_xZn_0.7-xFe₂O₄, (x = 0.00, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70) have been prepared by the standard ceramic techniques, sintered at 1200°C for 2 h, and their crystalline structures were investigated by using X-ray diffraction, which confirmed the formation of Ni_0.1Cu_0.2Mg_xZn_0.7-xFe₂O₄ phase. The presence of Mg content increases the crystallinity of the given ferrite which is considered as catalyst for the accomplishment of the solid state reaction. The lattice parameter and crystallite size were calculated from XRD. The cationic distribution was estimated from the theoretical values of lattice parameters. The IR spectra analysis has been studied.The dielectric constant for the ferrite system Ni–Cu–Zn gradually increases with temperature up to nearly Curie temperature and then increase sharply beyond the T_c. The Curie temperature obtained from the versus έ T is in agreement with the Curie temperature obtained from other measurements. Dielectric loss tangent (tan δ) has the same behavior as dielectric constant . (έ) A minimum value of dielectric loss tangent (tan δ) for the system "Ni–Cu–Zn" was observed at x = 0.45. Magnetic permeability has been studied. The dependence of initial permeability on temperature exhibit a peak which is called Hopkinson peak (HP) in the vicinity of Curie temperature and confirmed the phase purity of ferrite sample. The increasing of porosity and decreasing of grain size play an important role in decreasing μ_i. It is clear that the value of T_c is found to increase by increasing the concentration of diamagnetic substitution Mg for "Ni–Cu–Zn" system. [ABSTRACT FROM AUTHOR]