Study of cation distribution, structural and electrical properties of Al-Zn substituted Ni-Co ferrite

In the present study, Nanocrystalline Ni0.5-xZnxCo0.5Fe2-yAlyO4 (0 <= x <= 0.5 and 0 <= y <= 1.0) powders were fabricated via the sol-gel auto-combustion route. X-ray diffraction study revealed that the formation of single-phase Al-Zn substituted Ni-Co ferrites which have a cubic spinel structure. The lattice parameter shows a decreasing trend from 8.344 to 8.289 angstrom with the composition of Al3+-Zn2+. The range of crystallite size calculated from the Scherer formula is 46-6.9 nm. Cation distribution indicates that Zn2+ strongly occupies tetrahedral A-site and Al3+ ions occupied both tetrahedral A-site and octahedral B-site for all composition. Using the vibrating sample magnetometer, it is observed that the Coercive field (Hc), saturation magnetization (Ms), rotational permeability (mu(rk)), anisotropy field (Ha) and anisotropy constant (K-1) decreases with increasing the composition of Al3+-Zn2+. Fabricated samples show normal dielectric behavior and dielectric constant is increased with an increase of Al-Zn concentration.