Effect of Al2O3 Additive on the Soft Magnetic Properties of High-Bs Fe-Co-Al-O Films on a Thin Underlayer

Abstract

To understand the origin of the soft magnetic properties of Fe-Co system films with a high saturation magnetic flux density (B s), structural analysis was performed by conducting detailed X-ray diffraction (XRD) measurements and transmission electron microscope (TEM) observations in a wide range of film thicknesses and Al 2O3 compositions. An initial growth layer with small grains, a continuous columnar structure, and alternation of the crystal orientation according to the film thickness are important for obtaining good soft magnetic properties in a wide range of film thicknesses. These features can be obtained by using a combination of an Al 2O3 additive of about 1-3 at% and a thin underlayer. The mechanism of the soft magnetic properties of Fe-Co system films seems to be partially explained by the existence of an initial growth layer with good soft magnetic properties and the exchange-coupling effect with the initial growth layer.

Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

“…C, CoPt-TiO 2 , and Ru are a protective, a recording, an intermediate layer, respectively. The B s of an FeCo SUL was 2.45 T. IrMn was used as an fcc underlayer to obtain soft magnetic properties in the FeCo film [5][6][7], and an antiferromagnetic layer to pin the FeCo film [8]. A Pt underlayer is effective in increasing the crystal orientation of the IrMn, which is necessary to enhance the exchange coupling energy between FeCo and IrMn films.…”