SNR Impact of Magnetic Capping Layer in Granular FePt-L1₀ Media

In this work, we present a micromagnetic modeling study on a scheme to enhance the medium signal-to-noise ratio (SNR) in heat-assisted magnetic recording (HAMR). The micromagnetic model that incorporates the perpendicular L1(0) ordering with the Fe/Pt superlattice is employed in this study, which enables the modeling of media with separate magnetic properties for each individual layer. By adding a relatively thin Co-based magnetic capping layer on top of FePt-L1(0) granular thin film, the simulation study finds that the recording performance can be significantly improved, especially at high linear densities, provided the capping layer has significantly higher Curie temperature than that of FePt-L10 material. The study also found that the enhancement of adding the capping layer reaches saturation at 2 nm thickness. The SNR gain also increases monotonically as the capping layer anisotropy field decreases from 3 to 10 kOe.