Magnetic recording capping layer with multiple layers for controlling anisotropy for perpendicular recording media
View Patent ↗A method is described for improving recording performance of a perpendicular media. The method includes controlling the anisotropy levels in different sublayers of the magnetic recording layers of the perpendicular media. Further, the different sublayers thicknesses can be altered to match the media to a particular head.
1. A perpendicular recording media for a hard disk drive including:
a substrate;
a soft under layer above the substrate;
a magnetic recording layer above the soft underlayer comprising a magnetic sublayer;
an exchange coupling layer above the magnetic sublayer, and a cap layer above the exchange coupling layer; and an overcoat above the magnetic recording layer, wherein the cap layer includes a bottom cap layer with a anisotropy (Ms) between 375 and 550 emu/cc and a top cap layer with an Ms between 250 emu/cc and 375 emu/cc;
wherein the bottom cap layer is between 2.5 nm and 4 nm and the top cap layer is between 0.6 nm and 2 nm.
2. The perpendicular recording media of claim 1 , wherein the magnetic sublayer includes an oxide.
3. The perpendicular recording media of claim 2 , wherein the bottom cap layer has an Ms between 400 emu/cc and 500 emu/cc.
4. The perpendicular recording media of claim 2 , wherein the top cap layer has an Ms between 290 emu/cc and 340 emu/cc.
5. The perpendicular recording media of claim 2 , wherein the thickness ratio of the top cap layer to the bottom cap layer is between 0.1 and 1.
6. The perpendicular recording media of claim 5 , wherein the thickness ratio of the top cap layer to the bottom cap layer is between 0.3 and 0.7.
7. The perpendicular recording media of claim 2 , wherein the bottom cap layer has an Ms between 400 emu/cc and 500 emu/cc and the top cap layer has an Ms between 290 emu/cc and 340 emu/cc.
8. The perpendicular recording media of claim 7 , wherein the thickness ratio of the top cap layer to the bottom cap layer is between 0.1 and 1.
9. The perpendicular recording media of claim 8 , wherein the thickness ratio of the top cap layer to the bottom cap layer is between 0.2 and 0.7.
10. A perpendicular recording media including:
a substrate;
a soft under layer above the substrate;
a magnetic recording layer above the soft underlayer comprising a magnetic sublayer;
an exchange coupling layer above the magnetic sublayer;
and a cap layer above the exchange coupling layer;
and an overcoat above the magnetic recording layer,
wherein the cap layer includes a bottom cap layer with an anisotropy (Ms) between 200 and 400 emu/cc and a top cap layer with an Ms between 400 emu/cc and 700 emu/cc;
wherein the top cap layer is between 2 nm and 10 nm and the bottom cap layer is between 1 nm and 5 nm.
11. The perpendicular recording media of claim 10 , wherein the magnetic sublayer includes an oxide.
12. The perpendicular recording media of claim 11 , wherein the bottom cap layer has an Ms between 250 emu/cc and 350 emu/cc.
13. The perpendicular recording media of claim 12 , wherein the top cap layer has an Ms between 500 emu/cc and 600 emu/cc.
14. The perpendicular media of claim 11 , wherein the bottom cap layer has an Ms between 250 emu/cc and 350 emu/cc and the top cap layer has an Ms between 500 emu/cc and 600 emu/cc.
15. The perpendicular media of claim 11 , wherein
the top cap layer is between 2 nm and 10 nm and the bottom cap later is between 1 nm and 5 nm; and
the exchange coupling layer is between 0.5 nm and 2 nm.
16. The perpendicular media of claim 14 , wherein
the top cap layer is between 2 nm and 10 nm and the bottom cap later is between 1 nm and 5 nm; and
the magnetic sublayer including an oxide is between 5 nm and 20 nm.