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 (/spl sim/50 /spl Aring/) epitaxial Fe/sub 3/O/sub 4/ sublayer was formed in the as-deposited amorphous precursor grown on sapphire [001]. The nucleation of crystalline /spl alpha/-Fe/sub 2/O/sub 3/ phase from the amorphous precursor started at 300/spl deg/C and continued at higher annealing temperatures. The mosaic distribution of the /spl alpha/-Fe/sub 2/O/sub 3/ grains was about 0.67/spl deg/ full-width at half-maximum (FWHM), relatively large compared to that of the Fe/sub 3/O/sub 4/ sublayer. The crystalization of the Ba-ferrite phase occurred at 600/spl deg/C. The Fe/sub 3/O/sub 4/ sublayer was transformed from 600/spl deg/C to extremely well-aligned (0.05/spl deg/ FWHM) /spl alpha/-Fe/sub 2/O/sub 3/ phase. It is noteworthy that the crystallization of the Ba-ferrite phase occurred duping the transformation of the Fe/sub 3/O/sub 4/ sublayer to the well-aligned /spl alpha/-F/sub 2/O/sub 3/ grains. The Fe/sub 3/O/sub 4/ sublayer might play an important role in the crystallization of amorphous Ba-ferrite film.