CoCrPt-oxide based perpendicular recording media with hybrid soft magnetic underlayers

Writability of magnetic recording media with high anisotropy constant (Ku) is one of the major challenges encountered in extremely high density recording. A possible avenue to improve writability in perpendicular magnetic recording is to reduce the spacing between the writing head and the soft magnetic underlayer (SUL) or head-to-keeper spacing (HKS). A hybrid layer structure for reducing the HKS between the SUL and the writing head is investigated. The proposed structure makes use of a crystalline SUL with in-plane anisotropy together with an amorphous SUL to form a hybrid SUL (H-SUL). The H-SUL design helps to achieve better surface smoothness, thinner HKS, and good c -axis dispersion for the recording layer while still maintaining small and exchange-decoupled grains. Micromagnetic simulation demonstrates that the H-SUL scheme helps in improving writing field effectiveness and increasing field gradient along down-track and cross-track directions.