Synthesis and magnetic studies of pure and doped NiZn ferrite films using Sol gel method

In this work, the effect of Co and Cu doping on the magnetic properties of Nickel Zinc ferrite films was investigated. Three types of films with composition Ni0.5Zn0.5Fe2O4, Ni0.35Cu0.2Zn0.45Fe2O4 and Ni0.35Co0.2Zn0.45Fe2O4 were prepared using the sol-gel method. These films were annealed at 500, 600, 700 and 800 degrees C using a rapid thermal annealing furnace. XRD diffraction confirmed the formation of single-phase spinel structure in these films. Magnetic properties such as saturation magnetization (Ms) and coercivity of these films were measured using an alternating gradient magnetometer. The highest values of Ms were obtained for films annealed at 600 degrees C which are 350, 334 and 261 emu/cm3 for undoped, Co doped and Cu doped films, respectively. The corresponding coercivity values of these films were 102, 509 and 95 Oe. Thus, Co0.2 doping resulted in an increase in the coercivity whereas Cu0.2 doping reduced the coercivity. Grain size distribution was measured using a scanning electron microscope. It was observed that at higher annealing temperatures (above 600 degrees C), films developed cracks which results in the reduction of the saturation magnetization from such films.