Impact of chemical segregation on magnetic anisotropy of iron oxide films.

• Iron oxide films with variable magnetic anisotropy made by magnetron sputtering. • High resolution X-ray spectroscopy insights chemical phase composition. • Hard X-ray magnetometry extracts substrate-free magnetization profiles. • Coexistence of ferromagnetic and (super)paramagnetic components is proved. • Vertically elongated magnetite intrusions enhance perpendicular magnetic anisotropy. Texture-induced magnetic anisotropy is realized in iron oxide thin films deposited at room temperature onto Si(1 0 0) substrates using reactive magnetron sputtering of a Fe 2 O 3 target. Diversities in morphology and magnetic properties are evidenced by electron microscopy and vibrating sample magnetometry. Additional insight provided by X-ray absorption spectroscopy and X-ray magnetic circular dichroism reveals fundamental differences in chemical composition and element selective magnetic properties between the films deposited in the presence of Ar and N 2 reactive gas. Taking advantage of hard X-ray magnetometry, substrate-free magnetization profiles of the films were derived and deconvoluted into major magnetic components. In addition to ferromagnetic components with anisotropy defined by texture a significant contribution of (super)paramagnetic components due to rich interface structure of these nanocomposite films is observed. [ABSTRACT FROM AUTHOR]