Soft magnetic and crystallographic properties of Ni81Fe 19/Co67Cr33 multilayers as backlayers in perpendicular recording media

Multilayers composed of Ni₈₁Fe₁₉ and paramagnetic Co₆₇Cr₃₃ interlayers were prepared by facing targets sputtering as backlayers for perpendicular magnetic recording media. This multilayered film must satisfy the requirements for both improvement of (111) plane orientation and for providing excellent soft magnetic properties. Co₈₃Cr₁₇ recording layers deposited onto [Ni₈₁Fe₁₉/Co₆₇Cr₃₃(50 Å)]_n multilayers exhibited good c-axis orientation as a consequence of lattice matching with the (111) oriented fcc Ni-Fe plane. This effect was further improved by depositing the multilayer on to paramagnetic Co₆₇Cr₃₃ layers. Soft magnetic properties of Ni-Fe layers were also improved by forming multilayered structure. Ferromagnetic resonance (FMR) studies indicated that there is no significant interdiffusion in the multilayered structure. FMR also suggest that one of the origins of soft magnetism in the multilayers was related to the reduction of inhomogeneity of localized anisotropy. Increased Knoop hardness of the multilayers was also observed using multilayers