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The magnetic and structural properties of graded media fabricated by ion implantation of nitrogen (14 N+), oxygen (16O+), and cobalt (59Co+) ions in the CoCrPt–SiO2 recording layer of prototype disk have been studied. Ion implantation of the species was controlled at the atomic scale to fabricate the graded media. Magnetometric measurements indicated that the coercivity was reduced with an increasing dose of the implanted species. The observation of an increase in magnetic domain size has been attributed to the reduction in magnetocrystalline anisotropy energy, which is desirable for achieving graded media. The study indicates that the magnetic properties can be tailored by the appropriate selection of the implantation dose and species.

Ion implantation is a promising technique for fabricating high density bit patterned media (BPM) as it may eliminate the requirement of disk planarization. However, there has not been any notable study on the impact of implantation on BPM fabrication of FePt, particularly at nano-scale, where the lateral straggle of implanted ions may become comparable to the feature size. In this work, implantation of antimony ions in patterned and unpatterned L10-FePt thin films has been investigated. Unpatterned films implanted with high fluence of antimony exhibited reduced out-of-plane coercivity and change of magnetic anisotropy from perpendicular direction to film-plane. Interestingly, for samples implanted through patterned masks, the perpendicular anisotropy in the unimplanted region was also lost. This noteworthy observation can be attributed to the displacement of Fe and Pt atoms from the implantation sites to the unimplanted areas, thereby causing a phase disorder transformation from L10 to A1 FePt.

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