Structural, microstructural, magnetic and optical behaviour of nanostructured Ni0.5Zn0.5Fe2O4 thin films

Abstract

Ni0.5Zn0.5Fe2O4 (Ni-Zn) nanocrystalline thin films were deposited on Si and quartz substrates by metallo-organic decomposition (MOD) method using spin coating technique. The films were annealed at different temperature ranging from 4500 to 7000C for 2h. The structural properties of the samples were studied by X-ray diffraction and atomic force microscope. The influence of annealing temperature on, microstructure and magnetic properties of Ni0.5Zn0.5Fe2O4 thin films has been systematically investigated. The X-ray diffraction patterns confirm the formation of cubic spinel structure in these samples. The crystalline orientation of the films is changed from (311) to (400) on increasing annealing temperature to 5500C. The crystallite size also increases from ~ 12 to 16nm. The maximum magnetization value Ms ~302 emu/cm3, was measured for Ni-Zn thin films annealed at 7000 C. The nanocrystalline thin films have shown superparamagnetic characteristic. The optical properties of Ni0.5Zn0.5Fe2O4 thin film annealed at 7000C were investigated. The optical parameters such as refractive index (n), extinction coefficient (k), energy band gap, optical dielectric constant and conductivity have been extracted from the transmission spectrum measured in the wavelength range 400 -1100nm. The refractive index and extinction coefficients of the Ni-Zn film were obtained by the Swanepoel method.