Magnetic recording head including background magnetic field generator
View Patent ↗A perpendicular recording head ( 10 ) for use with magnetic recording media ( 30 ) includes a main pole ( 14 ) and a magnetic field source which is positioned sufficiently close to the main pole tip to generate a background magnetic field in the recording media. A conductive magnetizing coil ( 20 ) surrounding the main pole is preferably used as the magnetic field source. The background magnetic field generated by the magnetizing coil effectively reduces the coercivity of the magnetic recording media in the region affected by the background field. The recording head enables writing on high coercivity/high anisotropy magnetic media, thereby achieving extremely high recording densities.
1. A perpendicular recording head for use with a magnetic recording medium, the perpendicular recording head comprising:
a main pole having a tip;
a yoke connected to the main pole having a thickness greater than a thickness of the main pole; and
an electrically conductive magnetizing coil at least partially surrounding the yoke and positioned sufficiently close to the main pole tip to generate a background magnetic field in the magnetic recording medium when current is passed through the magnetizing coil, wherein the current passed through the magnetizing coil is sufficient to cause magnetic saturation of the main pole tip, and the combination of a magnetic field generated from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium.
2. The perpendicular recording head of claim 1 , wherein the magnetizing coil at least partially surrounds the main pole.
3. The perpendicular recording head of claim 2 , wherein the magnetizing coil comprises a single winding around the main pole.
4. The perpendicular recording head of claim 1 , wherein the magnetizing coil is spaced apart from an outer surface of the yoke.
5. The perpendicular recording head of claim 1 , wherein the magnetizing coil is positioned directly adjacent an outer surface of the yoke.
6. The perpendicular recording head of claim 1 , wherein the magnetizing coil is at least partially embedded in an outer surface of the yoke.
7. The perpendicular recording head of claim 1 , wherein the ratio of the yoke thickness to the main pole thickness is less than about 10:1.
8. The perpendicular recording head of claim 1 , wherein the ratio of the yoke thickness to the main pole thickness is from about 2:1 to about 5:1.
9. The perpendicular recording head of claim 2 , wherein the magnetizing coil has a radial dimension R measured from an axis defined by the main pole, the magnetizing coil has a pole tip distance D measured from the magnetizing coil to the pole tip in a direction parallel with the main pole axis, and the ratio of R:D is from about 1:1 to about 10:1.
10. The perpendicular recording head of claim 9 , wherein the ratio of R:D is from about 1:1 to about 10:1.
11. The perpendicular recording head of claim 9 , wherein the radial dimension R is from about 0.1 to about 5 micron.
12. The perpendicular recording head of claim 9 , wherein the pole tip distance D is from about 0.1 to about 5 micron.
13. The perpendicular recording head of claim 1 , wherein the background magnetic field is greater than 100 Gauss.
14. The perpendicular recording head of claim 1 , wherein the background magnetic field is greater than 1,000 Gauss.
15. The perpendicular recording head of claim 1 , wherein the background magnetic field is greater than 2,000 Gauss.
16. The perpendicular recording head of claim 1 , wherein the background magnetic field is from about 5,000 to about 10,000 Gauss.
17. The perpendicular recording head of claim 1 , wherein the background magnetic field has a strength H b , a magnetic field generated at the main pole tip has a strength H p , and the ratio of H b :H p is from about 1:10 to about 10:1.
18. The perpendicular recording head of claim 17 , wherein the ratio of H b :H p is from about 4:10 to about 3:1.
19. A magnetic recording apparatus, comprising:
a magnetic recording medium including an upper layer having a plurality of data storage tracks, and a lower layer being magnetically soft relative to the data storage tracks; and
a recording head including a main pole having a tip, a yoke connected to the main pole having a thickness greater than a thickness of the main pole, and an electrically conductive magnetizing coil at least partially surrounding the yoke and positioned sufficiently close the main pole tip to generate a background magnetic field in the magnetic recording medium when the recording head is positioned at a flying height above the magnetic recording medium and current is passed through the magnetizing coil, wherein the current passed through the magnetizing coil is sufficient to cause magnetic saturation of the main pole tip, and the combination of a magnetic field generated from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium.
20. The magnetic recording apparatus of claim 19 , wherein the magnetizing coil at least partially surrounds the main pole.
21. The magnetic recording apparatus of claim 20 , wherein the magnetizing coil has a radial dimension R measured from an axis defined by the main pole, the magnetizing coil has a pole tip distance D measured from the magnetizing coil to the pole tip in a direction parallel with the main pole axis, and the ratio of R:D is from about 1:1 to about 10:1.
22. The magnetic recording apparatus of claim 20 , wherein the background magnetic field has a strength H b , a magnetic field generated at the main pole tip has a strength H p , and the ratio of H b :H p is from about 1:10 to about 10:1.
23. The magnetic recording apparatus of claim 19 , wherein the magnetizing coil generates a magnetic field at the main pole tip in addition to the background magnetic field that is generated when the current is passed through the magnetizing coil.
24. A method of storing data on a magnetic storage medium, the method comprising the steps of:
providing a magnetically permeable main pole having a tip;
providing a yoke connected to the main pole having a thickness greater than a thickness of the main pole;
providing an electrically conductive magnetizing coil at least partially surrounding the yoke adjacent to the main pole tip;
providing a magnetic storage medium adjacent the main pole tip;
passing current through the magnetizing coil sufficient to cause magnetic saturation of the main pole tip;
directing a magnetic field from the saturated main pole tip toward the magnetic storage medium; and
additionally generating a background magnetic field in the magnetic storage medium from the magnetizing coil, wherein the combination of the magnetic field from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium.