Magnetic, Electric and Optical Properties of Mg-Substituted Ni-Cu-Zn Ferrites

The Ni0.25-x Mg (x) Cu0.30Zn0.45Fe2O4 (x = 0.00 mol, 0.05 mol, 0.10 mol, 0.15 mol, 0.20 mol and 0.25 mol) magnetic oxide system was prepared by a sol-gel auto--combustion method using glycine as a fuel. X-ray diffraction study reveals the formation of pure spinel lattice symmetry along with the presence of a small fraction of unreacted Fe2O3 phase as a secondary phase due to incomplete combustion reaction between fuel and oxidizer. The lattice constant (a) was found to decrease with the increase of Mg2+ content; the average crystallite size (D) is observed in the range of 26.78-33.14 nm. At room temperature, all the samples show typical magnetic hysteresis loops with the decrease of magnetic moment (n (B)) of Ni-Cu-Zn ferrites with the increase of Mg2+ content. The intrinsic vibrational absorption bands for the tetrahedral and octahedral sites of the spinel structure were confirmed by infrared (IR) spectroscopy. The optical parameters such as refractive index (eta), velocity of IR waves (v) and jump rates (J (1), J (2), J) were studied and found to be dependent on the variation of the lattice constant. The Curie temperature (T (c)) of Ni-Cu-Zn mixed ferrite was found to decrease with Mg2+ addition. The composition x = 0.15 mol.% with a low dielectric loss tangent of 2% seems to have potential for multilayer chip inductor applications at a wide range of frequencies.