Transverse biased shields for perpendicular recording to reduce stray field sensitivity
View Patent ↗A method for reducing flux concentrating capacity of a shield in a magnetic read/write head positioned to read perpendicular residual magnetic fields on a magnetic media. Permeability of the shield is reduced in a direction oriented perpendicular to the magnetic media by inducing a transverse magnetic bias field within the shield.
1. A perpendicular magnetic head comprising:
a magnetoresistive read device positioned to read perpendicular residual magnetic fields on a magnetic media in proximity with the read device;
a shield at least partially surrounding the read device comprising a magnetic material having an orientation selected to capture stray magnetic fields; and
a transverse magnetic bias field within the shield.
2. The magnetic head of claim 1 wherein the transverse magnetic field is in the range of 30–500 Oe.
3. The magnetic head of claim 1 wherein the transverse magnetic bias is applied by exchange pinning technique.
4. The magnetic head of claim 1 wherein the transverse magnetic bias is applied by field anneal to induce magnetocrystalline anisotropy.
5. The magnetic head of claim 1 wherein the transverse magnetic bias is applied by stress-induced magnetocrystalline anisotropy.
6. The magnetic head of claim 1 wherein the read device comprises a giant magnetoresistive device.
7. A method for reducing flux concentrating capacity of a shield, said shield at least partially surrounding a magnetoresistive read device positioned to read perpendicular residual magnetic fields on a magnetic media, said method comprising:
reducing permeability of said shield in a direction oriented perpendicular to said magnetic media by inducing a transverse magnetic bias field within said shield.
8. The method of claim 7 , wherein said step of inducing a transverse magnetic bias field within the shield further comprises inducing said transverse magnetic field bias within said shield by an exchange pinning technique.
9. The method of claim 7 , wherein said step of inducing a transverse magnetic bias field within the shield further comprises inducing said transverse magnetic field bias within said shield by field anneal to induce magnetocrystalline anisotropy.
10. The method of claim 7 , wherein said step of inducing a transverse magnetic bias field within the shield further comprises inducing said transverse magnetic field bias within said shield by stress-induced magnetocrystalline anisotropy.
11. A perpendicular magnetic head for a disk drive with a magnetic media having perpendicular residual magnetic fields, said perpendicular magnetic head comprising:
a shield associated with the magnetic media, said shield comprising a magnetic material having an orientation selected to capture stray magnetic fields; and
a transverse magnetic bias field within the shield.
12. The magnetic head of claim 11 wherein the transverse magnetic field is in the range of 30–500 Oe.
13. The magnetic head of claim 11 wherein the transverse magnetic bias is applied by exchange pinning technique.
14. The magnetic head of claim 11 wherein the transverse magnetic bias is applied by field anneal to induce magnetocrystalline anisotropy.
15. The magnetic head of claim 11 wherein the transverse magnetic bias is applied by stress-induced magnetocrystalline anisotropy.
16. A magnetic data storage device comprising:
a perpendicular recording medium;
a read/write head, including a read element and a write element;
drive electronics coupled to position the read/write head over selected locations of the perpendicular recording medium;
a shield, at least partially surrounding the read element, comprising a magnetic material having an orientation selected to capture stray magnetic fields; and
a transverse magnetic bias field within the shield.
17. The magnetic data storage device of claim 16 wherein the transverse magnetic field is in the range of 30–500 Oe.
18. The magnetic data storage device of claim 16 wherein the transverse magnetic bias is applied by exchange pinning technique.
19. The magnetic data storage device of claim 16 wherein the transverse magnetic bias is applied by field anneal to induce magnetocrystalline anisotropy.
20. The magnetic data storage device of claim 16 wherein the transverse magnetic bias is applied by stress-induced magnetocrystalline anisotropy.
21. The magnetic data storage device of claim 16 wherein the read head comprises a giant magnetoresistive device.