Abstract
To realize higher areal density in hard disk drives (HDDs), it is necessary to develop soft magnetic materials with high saturation magnetic flux density (Bs) as pole tip materials for write heads. We have developed soft magnetic FeCoAlO films with a Bs of -2.4 T, which is close to the limit of Bs in thermal equilibrium ferromagnetic alloys. Uniaxial anisotropy is obtained in the as-made films without an applied field during sputtering. The films have sufficient magnetic thermal stability and corrosion resistance to withstand magnetic head fabrication processes. For write heads with pole tips composed of FeCoAlO films, the overwrite (O/W) is about -45 dB. Accordingly, it is established that ultrahigh Bs FeCoAlO films are effective for improving write performance.
