High performance perpendicular magnetic granular media consisting of multiple exchange control layers
A perpendicular magnetic recording media comprises a substrate, a first magnetic oxide layer, a first exchange control layer, a second magnetic oxide layer, a second exchange control layer, and a magnetic cap layer positioned above the substrate, in this order. The first magnetic oxide layer may have an anisotropy energy (Ku) between 6×10 6 and 8×10 6 erg/cm 3 , and a magnetization (Ms) between 600 and 800 emu/cm 3 . The second magnetic oxide layer may have a Ku between 5×10 6 and 8×10 6 erg/cm 3 , and an Ms between 550 and 750 emu/cm 3 . The first exchange control layer may have an Ms between 0 and 100 emu/cm 3 . The second exchange control layer may have an Ms between 0 and 40 emu/cm 3 .
1. A perpendicular recording media, comprising:
a substrate;
an underlayer, a first magnetic oxide layer, a first exchange control layer, a second magnetic oxide layer, a second exchange control layer, and a magnetic cap layer positioned above the substrate, in this order, wherein
the first magnetic oxide layer has an anisotropy energy (Ku) between 6×10 6 and 8×10 6 erg/cm 3 , and an magnetization (Ms) between 600 and 800 emu/cm 3 ;
the second magnetic oxide layer has a Ku between 5×10 6 and 8×10 6 erg/cm 3 , and an Ms between 550 and 750 emu/cm 3 ;
the first exchange control layer has an Ms between 0 and 100 emu/cm 3 ; and
the second exchange control layer has an Ms between 0 and 40 emu/cm 3 .
2. The perpendicular recording media of claim 1 , wherein:
a third magnetic oxide layer is positioned above the second exchange control layer.
3. The perpendicular recording media of claim 2 , wherein:
a third exchange control layer is positioned above the third magnetic oxide layer.
4. The perpendicular recording media of claim 3 , wherein:
the third exchange control layer has an Ms between 0 and 100 emu/cm 3 .
5. The perpendicular recording media of claim 2 , wherein:
the third magnetic oxide layer has a Ku between 4×10 6 and 7.5×10 6 erg/cm 3 , and an Ms between 500 and 750 emu/cm 3 .
6. The perpendicular recording media of claim 1 , wherein:
the first exchange control layer has a thickness less than 10 Å.
7. The perpendicular recording media of claim 1 , wherein
the underlayer includes at least one of ruthenium and ruthenium oxide.
8. The perpendicular recording media of claim 1 , wherein
the magnetic cap layer includes CoPtCr.
9. The perpendicular recording media of claim 1 , wherein
the magnetic oxide layers include CoPtCr-oxide.
10. The perpendicular recording media of claim 1 , wherein
the magnetic oxide layers have a substantially equal thickness.
11. The perpendicular recording media of claim 1 , wherein
the exchange control layers include CoCrRuB-oxide.
12. The perpendicular recording media of claim 1 , wherein
the exchange control layers have a substantially equal thickness.
13. The perpendicular recording media of claim 1 , wherein
a thickness ratio of the second exchange control layer to the first exchange control layer is between 1.4 and 1.6.
14. The perpendicular recording media of claim 1 , wherein
a product KuV/kT is between 92 and 95 for the second magnetic oxide layer, where Ku is an anisotropy energy of the second magnetic oxide layer, V is a volume of magnetic grains in the second magnetic oxide layer, k is Boltzman's constant, and T is an absolute temperature of the second magnetic oxide layer at storage temperatures.
15. The perpendicular recording media of claim 1 , wherein
the underlayer may further include AF coupled CoFeTaZr soft-magnetic layers.
16. The perpendicular recording media of claim 1 , wherein
the underlayer may further include a NiW alloy seed layer.
17. The perpendicular recording media of claim 1 , wherein
the magnetic oxide layers and the exchange control layers are configured to provide the perpendicular recording media with a media writeability of between 35 and 37 dB.
18. The perpendicular recording media of claim 1 , wherein
the magnetic oxide layers and exchange control layers are configured to provide the perpendicular recording media with a recording performance such that +0.9 order bit error rate, +0.8 dB signal-to-noise ratio, +1.8 dB overwrite, and +1.5% resolution are achieved.
19. A perpendicular recording media, comprising:
a substrate;
a first magnetic oxide layer, a first exchange control layer, a second magnetic oxide layer, a second exchange control layer, a third magnetic oxide layer, a third exchange control layer, and a magnetic cap layer positioned above the substrate, in this order, wherein
the first magnetic oxide layer has an anisotropy energy (Ku) between 6×10 6 and 8×10 6 erg/cm 3 , and an magnetization (Ms) between 600 and 800 emu/cm 3 ;
the second magnetic oxide layer has a Ku between 5×10 6 and 8×10 6 erg/cm 3 , and an Ms between 550 and 750 emu/cm 3 ;
the third magnetic oxide layer has a Ku between 4×10 6 to 7.5×10 6 erg/cm 3 , and an Ms between 500 and 750 emu/cm 3 ;
the first exchange control layer has an Ms between 0 and 100 emu/cm 3 ;
the second exchange control layer has an Ms between 0 and 40 emu/cm 3 ; and
the third exchange control layer has an Ms between 0 and 100 emu/cm 3 .
20. A perpendicular recording media, comprising:
at least one underlayer;
a substrate, a first magnetic oxide layer, a first exchange control layer, a second magnetic oxide layer, a second exchange control layer, a third magnetic oxide layer, a third exchange control layer, and a magnetic cap layer; wherein
the first magnetic oxide layer has an anisotropy energy (Ku) between 6×10 6 and 8×10 6 erg/cm 3 , and an magnetization (Ms) between 600 and 800 emu/cm 3 ;
the second magnetic oxide layer has a Ku between 5×10 6 and 8×10 6 erg/cm 3 , and an Ms between 550 and 750 emu/cm 3 ;
the third magnetic oxide layer has a Ku between 4×10 6 to 7.5×10 6 erg/cm 3 , and an Ms between 500 and 750 emu/cm 3 ;
the first exchange control layer has an Ms between 0 and 100 emu/cm 3 ;
the second exchange control layer has an Ms between 0 and 40 emu/cm 3 ;
the third exchange control layer has an Ms between 0 and 100 emu/cm 3 ; and
the first exchange control layer has a thickness less than 10 Å.