Structural and magnetic properties of NiCuZn ferrite films deposited using sputtering

Ferrite films are promising materials for power inductor applications. In this work, we investigated the structural and magnetic properties of Ni0.35Cu0.2Zn0.45Fe2O4 films to understand the correlation between annealing temperature, grain size, crystallite size, lattice constant, microstrain, dislocation density, and magnetic properties. The films were deposited at room temperature on Si substrates using sputtering method. Films were annealed post-deposition to tune the microstructure. The crystallinity and spinel structure of the films were confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy revealed that films were crack-free, and a linear growth in the grain size with an increase in annealing temperature was observed. The crystallite size, lattice constant, microstrain, and dislocation density calculated from the XRD data indicate that the lattice imperfection decreased when films were annealed at higher temperatures, resulting in an increase in the value of saturation magnetization. Crack-free films with maximum saturation magnetization of 387 emu/cc were obtained from the film annealed at 800 °C.