American Institute of Physics, Journal of Applied Physics, 10(104), p. 103905
DOI: 10.1063/1.3013883
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Writability of magnetic recording media with high anisotropy constant (K(u)) 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.