发明名称 |
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. |
申请公布号 |
US9406328(B2) |
申请公布日期 |
2016.08.02 |
申请号 |
US201414446193 |
申请日期 |
2014.07.29 |
申请人 |
HGST Netherlands B.V. |
发明人 |
Tonooka Shun;Shimizu Masayoshi;Nakagawa Hiroyuki;Tanahashi Kiwamu |
分类号 |
G11B5/706;G11B5/667;G11B5/716;G11B5/65;G11B5/66 |
主分类号 |
G11B5/706 |
代理机构 |
Zilka-Kotab, PC |
代理人 |
Zilka-Kotab, PC |
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. |
地址 |
Amsterdam NL |