Spinel ferrite Co-γFe2O3 perpendicular media on exchange-coupled underlayers

Spinel ferrite Co-γFe 2 O 3 films have advantages of high coercivity, high stability without protective layer, and low noise performance for magnetic recording layer. Also, exchange-coupled Co-Zr-Nb/Co-Sm underlayers showed superior characteristics. The Co-Sm hard magnetic layer pinned the domains of Co-Zr-Nb soft magnetic layer effectively and decreased the noise coming from the soft magnetic layer. Combining the Co-γFe 2 O 3 recording layer and exchange-coupled Co-Zr-Nb/Co-Sm underlayers, the triple-layered perpendicular media showed abilities for ultrahigh-density perpendicular recording.