Annealing Effects on Semitransparent and Ferromagnetic ZnFe2O4 Nanostructured Films by Sol-Gel

ZnFe2O4 films have been prepared using a sol-gel route. The influences of annealing temperature as well as annealing atmosphere on the structural, morphological, magnetic, and optical properties were investigated. The TEM and SEM images show that ZnFe2O4 films are polycrystalline in nature and homogeneous with densely packed grains. ZnFe2O4 films exhibit ferromagnetic behavior at 300 K and high transparency (>= 80%) above the absorption band edge. With decreasing annealing temperature and annealing oxygen partial pressure, the saturated magnetism at 300 K is improved and the optical band gap is decreased. The reasons are discussed, and the results show that semitransparent ZnFe2O4 films with room-temperature ferromagnetism can be successfully prepared using a sol-gel method.