Crystallization of amorphous precursor of Ba-ferrite film: A real-time synchrotron X-ray scattering study

Abstract

The crystallization of the amorphous precursor of a Ba-ferrite thin film was studied in real-time synchrotron x-ray scattering experiments. We found that a very thin (similar to 50 Angstrom) epitaxial Fe3O4 sublayer was formed in the as-deposited amorphous precursor grown on sapphire (001), The nucleation of crystalline alpha-Fe2O3 phase from the amorphous precursor started at 300 degrees C and continued at higher annealing temperatures. The mosaic distribution of the alpha-Fe2O3 grains was about 0.67 degrees full-width at half-maximum (FWHM), relatively large compared to that of the Fe3O4 sublayer, The crystallization of the Ba-ferrite phase occurred at 600 degrees C, The Fe3O4 sublayer was transformed from 600 degrees C to extremely well-aligned (0.05 degrees FWHM) alpha-Fe2O3 phase. It is noteworthy that the crystallization of the Ba-ferrite phase occurred during the transformation of the Fe3O4 sublayer to the well-aligned alpha-Fe2O3 grains, The Fe3O4 sublayer might play an important role in the crystallization of amorphous Ba-ferrite film.