Si/NiFe/FeCoB Crystalline SUL to Reduce Ru Intermediate Layer Thickness for CoPtCr-SiO$_{2}$ Granular Perpendicular Magnetic Recording Media

Bcc-FeCo (110) textured Ru/FeCoB films with high in-plane anisotropy field Hk were prepared as crystalline soft magnetic underlayers (SULs). The differences in crystallographic texture of the Ru intermediate layer (IML) and magnetic properties of Ru/CoPtCr-SiO
₂
films with or without a FeCoB crystalline SUL were investigated. Ru/CoPtCr-SiO
₂
films without Ru/FeCoB SULs exhibited a random orientation of Ru crystallites and in-plane magnetic anisotropy. On the other hand, Ru/CoPtCr-SiO
₂
films deposited on the Ru/FeCoB SULs exhibited (001) preferential orientations of the CoPtCr as well as the Ru IMLs and possessed perpendicular magnetic anisotropy. The reduction of the thickness of the Ru IML from 30 nm to 1 nm did not cause the degradation of integrated intensity of the CoPtCr (002) diffraction peak. The application of the Si/NiFe/FeCoB SUL improved the FeCo (110) crystalline orientation, compared to the Ru/FeCoB SUL, and promoted (001) crystalline orientation of the CoPtCr-SiO
₂
granular recording layer. The correlative relationship between Deltathetas
₅₀
of FeCo (110) texture and that of CoPtCr (002) texture was confirmed.