Effect of thermal annealing on the film and substrate/film interface: the case of ZnFe2O4

Abstract

Herein, we reported the effect of thermal annealing on the ZnFe2O4 film and substrate/film interface. These films were grown on MgO(200) substrate using radio frequency sputtering and were further annealed at 200, 400, and 600 °C. The thickness of the as-grown film was 109 nm, which was observed to decrease with annealing due to the increase of film/substrate interface as determined from high-resolution electron microscopy (HRTEM). Zn K-edge X-ray absorption near edge structure (XANES) spectrum exhibits spectral features at 600 °C that are characteristics of ZnFe2O4. Annealing modulated the metal–oxygen hybridization process in these films as evidenced from the pre-edge region of O K-edge spectra. Selected area diffraction further envisages changes in the crystalline nature of films and interface regions.