Magnetic write head for providing spin-torque-assisted write field enhancement
Disclosed herein are magnetic write heads for providing spin-torque-assisted write field enhancement, and hard disk drives comprising such magnetic write heads. Within the write gap, each magnetic write head comprises a main pole, a trailing shield, a spacer disposed between the main pole and the trailing shield, a non-magnetic layer disposed between the main pole and the trailing shield, and a magnetic DC-field-generation (DFG) layer adjacent to the spacer and disposed between the spacer and the non-magnetic layer. In some embodiments, the DFG layer is the only magnetic layer within the write gap that is not adjacent to the main pole or the trailing shield.
1. A magnetic write head for providing spin-torque-assisted write field enhancement,
the magnetic write head comprising, within a write gap:
a main pole;
a trailing shield;
a spacer disposed between the main pole and the trailing shield, wherein the spacer is non-magnetic;
a non-magnetic layer disposed between the main pole and the trailing shield; and
a DC-field-generation (DFG) layer adjacent to the spacer and disposed between the spacer and the non-magnetic layer, wherein the DFG layer is magnetic,
wherein the DFG layer is the only magnetic layer within the write gap that is not adjacent to the main pole or the trailing shield.
2. The magnetic write head recited in claim 1 , wherein a thickness of an effective write gap including the spacer, the non-magnetic layer, and the DFG layer is between about 15 nm and about 25 nm.
3. The magnetic write head recited in claim 1 , wherein a product of a thickness of the DFG layer and a magnetic saturation flux density of the DFG layer is between about 3 nm×Tesla and about 9 nm×Tesla.
4. The magnetic write head recited in claim 1 , wherein a thickness of the spacer is between about 3 nm and about 5 nm, a thickness of the DFG layer is between about 3 nm and about 9 nm, and a thickness of the non-magnetic layer is between about 8 nm and about 19 nm.
5. The magnetic write head recited in claim 1 , wherein the spacer comprises copper, silver, gold, or an alloy comprising copper, silver, or gold.
6. The magnetic write head recited in claim 1 , wherein the spacer is adjacent to the main pole or adjacent to the trailing shield.
7. The magnetic write head recited in claim 1 , wherein the non-magnetic layer comprises at least one of nickel, chromium, aluminum, ruthenium, tantalum, or copper.
8. The magnetic write head recited in claim 1 , wherein the non-magnetic layer comprises a nickel-aluminum alloy or a nickel-chromium alloy.
9. The magnetic write head recited in claim 1 , wherein a magnetic saturation flux density of the DFG layer is between about 1 Tesla and about 1.5 Tesla.
10. The magnetic write head recited in claim 1 , wherein the DFG layer comprises:
a first layer comprising at least one of cobalt, iron, or a cobalt-iron alloy, wherein a thickness of the first layer is between about 0.2 nm and about 1 nm; and
a second layer comprising an alloy of cobalt, a first element, and a second element, wherein the first element is manganese or iron, and the second element is germanium, aluminum, silicon, or gallium, and wherein a thickness of the second layer is between about 2 nm and about 8 nm.
11. The magnetic write head recited in claim 10 , wherein the first layer comprises cobalt-iron, and the second layer comprises cobalt-manganese-germanium.
12. The magnetic write head recited in claim 10 , wherein the DFG layer further comprises:
a third layer comprising at least one of cobalt, iron, or a cobalt-iron alloy, wherein a thickness of the third layer is between about 0.2 nm and about 1 nm.
13. The magnetic write head recited in claim 12 , wherein the third layer comprises cobalt-iron.
14. The magnetic write head recited in claim 1 , wherein the DFG layer comprises:
a first layer comprising at least one of cobalt or a cobalt-iron alloy, wherein a thickness of the first layer is between about 0.2 nm and about 1 nm; and
a second layer comprising at least one of nickel, iron, or a nickel-iron alloy, wherein a thickness of the second layer is between about 2 nm and about 8 nm.
15. The magnetic write head recited in claim 14 , wherein the first layer comprises cobalt, and the second layer comprises nickel-iron.
16. The magnetic write head recited in claim 1 , further comprising a magnetic notch between the trailing shield and the main pole, wherein the trailing shield and the magnetic notch or the main pole and the magnetic notch are made of identical materials.
17. The magnetic write head recited in claim 1 , further comprising a magnetic notch between the trailing shield and the spacer, or between the main pole and the spacer.
18. The magnetic write head recited in claim 17 , wherein a thickness of the magnetic notch is between about 1 nm and about 10 nm.
19. A hard disk drive, comprising:
a magnetic disk; and
a magnetic write head for providing spin-torque-assisted write field enhancement, the magnetic write head comprising:
a main pole,
a trailing shield,
a spacer disposed between the main pole and the trailing shield, wherein the spacer is non-magnetic,
a non-magnetic layer disposed between the main pole and the trailing shield, and
a DC-field-generation (DFG) layer adjacent to the spacer and disposed between the spacer and the non-magnetic layer, wherein the DFG layer is magnetic, and wherein the DFG layer is the only magnetic layer within a write gap of the magnetic write head that is not adjacent to the main pole or the trailing shield.
20. The hard disk drive recited in claim 19 , wherein the DFG layer comprises:
a first layer comprising at least one of cobalt, iron, or a cobalt-iron alloy, wherein a thickness of the first layer is between about 0.2 nm and about 1 nm; and
a second layer comprising an alloy of cobalt, a first element, and a second element, wherein the first element is manganese or iron, and the second element is germanium, aluminum, silicon, or gallium, and wherein a thickness of the second layer is between about 2 nm and about 8 nm.
21. The hard disk drive recited in claim 19 , wherein the DFG layer comprises:
a first layer comprising at least one of cobalt or a cobalt-iron alloy, wherein a thickness of the first layer is between about 0.2 nm and about 1 nm; and
a second layer comprising at least one of nickel, iron, or a nickel-iron alloy, wherein a thickness of the second layer is between about 2 nm and about 8 nm.