Thickness effect on structural properties of post annealed barium hexaferrite films deposited by ion beam sputtering

•Annealing of BaFe12O19/Al2O3 (102) films led to the formation of a layered structure.•Surface layer of BaFe12O19/Al2O3 (102) films could have (00l) crystal texture.•The morphology of the surface BaFe12O19/Al2O3 (102) depends on the substrate temperature.•The thickness of BaFe12O19 film influences the type of its texture after annealing. Barium hexaferrite thin films were prepared by ion beam deposition on sapphire (102) single crystal substrates. The structural properties of the films were analyzed by means of X-ray diffraction, atomic force microscopy, magnetic force microscopy and scanning electron microscopy. The obtained results were interpreted as a presence of layered structure with different types of texture and its formation mechanism is proposed. The significant influence of BaFe12O19 thickness on its microstructure was observed. Films obtained under certain conditions are potentially fit for further growing of oriented hexaferrite with out-of-plane orientation of c-axis.