The effect of underlayer for Ba-ferrite sputtered films on c-axis orientation

A thin amorphous Ba–Fe–O film was deposited as an underlayer for the growth of c-axis oriented hexagonal barium ferrite (BaM) films using a facing targets sputtering system. This underlayer facilitates the crystallization and improves the crystallinity for hexagonal M phase. BaM films with c-axis orientation can be prepared at Ts of 525 °C on the underlayer. BaM films prepared on this amorphous underlayer exhibit a good c-axis orientation with c-axis dispersion angle Δθ50 as small as 3°. It is shown by the x-ray photoemission spectroscopy profile that this underlayer prevents deep diffusion of Ba and Fe into the substrate surface.