SOFT MAGNETIC UNDERLAYER HAVING HIGH TEMPERATURE ROBUSTNESS FOR HIGH AREAL DENSITY PERPENDICULAR RECORDING MEDIA

摘要

In one embodiment, a perpendicular magnetic recording medium includes: a substrate; and a soft magnetic underlayer structure positioned above the substrate, where the soft magnetic underlayer includes: a coupling layer; a first soft underlayer positioned above the coupling layer; and a second soft underlayer positioned below the coupling layer, where a difference between a magnetic flux density of the soft magnetic underlayer structure at 25° C. and a magnetic flux density of the soft underlayer structure at 85° C. is less than or equal to about 10% of the magnetic flux density of the soft magnetic underlayer structure at 25° C.

主权项

1. A perpendicular magnetic recording medium, comprising:
a substrate; and a soft magnetic underlayer structure positioned above the substrate, wherein the soft magnetic underlayer structure comprises:
a coupling layer;a first soft underlayer positioned above the coupling layer; anda second soft underlayer positioned below the coupling layer, wherein a difference between a magnetic flux density of the soft magnetic underlayer structure at 25° C. and a magnetic flux density of the soft underlayer structure at 85° C. is less than or equal to about 10% of the magnetic flux density of the soft magnetic underlayer structure at 25° C., wherein at least one of the soft underlayers comprises a soft magnetic alloy including Co and Fe, wherein an amount of Co in the soft magnetic alloy satisfies the condition:Co_c[Co_c+Fe_c]≥2-2·Bs(RT),where Co_C represents the atomic percentage of Co in the soft magnetic alloy, Fe_c represents the atomic percentage of Fe in the soft magnetic alloy, and Bs(RT) represents the magnetic flux density of the soft underlayer structure in Teslas.