Adjacent track readers

• US 7,755,863 B2
• Filed: 03/14/2006
• Issued: 07/13/2010
• Est. Priority Date: 03/14/2006
• Status: Active Grant

• Current Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: Buchan, William A., Neumann, Lawrence G.
• Primary Examiner(s): BLOUIN, MARK S
• Application Number:
  US11/376,588
• Publication Number:
  US 20070217078A1
• Time in Patent Office: 1,582 Days
• Field of Search: None
• US Class Current: 360/77.01
• CPC Class Codes: G11B 5/3958 the active elements being arranged in a single plane, e.g. "matrix" disposition

Abstract

Aspects include readers for magnetic storage media. Each reader is operable to read multiple tracks from the storage media simultaneously by using a plurality of active regions, each active region for reading a different track. The active regions may be disposed in rows of columns, and between rows, each active region in a row may be separated from other active regions in that row to prevent interference between those active regions. Active regions of different rows may be offset from each other such that no active region overlaps with another active region over the same data track. Active regions may share shielding and/or sense current conductors. Active regions may comprise AMR, CIP GMR, CPP GMR, including spin valve and tunneling varieties of flux sensors. Multiple active regions in a row may be defined from a single MR element by spaced apart voltage tabs. Readers may be integrally fabricated in layers.

Claims

1. A reader for reading from a magnetic storage device, the reader comprising:

a first row of a plurality of magnetoresistive active regions for sensing magnetic flux indicative of stored data, each active region separated from nearest active regions in the first row by respective inactive regions; and

a second row of a plurality of active regions, each active region of the second row separated from nearest active regions in the second row by respective inactive regions, wherein each active region in the second row is columnwise offset from active regions in the first row by about a width of the active regions.

2. The reader of claim 1, wherein each inactive region is at least as wide as the active regions.

3. The reader of claim 2, wherein each inactive region is wider than the active regions by a guard band distance.

4. The reader of claim 3, wherein the guard band distance is smaller than half the width of the active region.

5. The reader of claim 2, wherein the guard band distance is between 0.1 microns and 0.5 microns wide.

6. The reader of claim 1, wherein active regions of the first row overlap with corresponding active regions of the second row by a distance that is small compared with the width of the active regions.

7. The reader of claim 1, further comprising:

a third row of a plurality of active regions, each active region of the third row separated from nearest active regions in the third row by an inactive region approximately at least twice the width of the active region, wherein

the respective inactive regions separating active regions in the first row and active regions in the second row are each approximately at least twice the width of each active region, and active regions in the first, second and third rows are columnwise offset from each other by approximately the width of the active regions.

8. The reader of claim 1, wherein each active region is coupled with a source of a current and a sink of the current, and the inactive regions respectively include a first and a second permanent magnet for biasing the active regions.

9. The reader of claim 8, wherein the first permanent magnet and the second permanent magnet respectively function as the source of current and the sink of the current.

10. The reader of claim 1, wherein each active region shares a biasing permanent magnet with at least one other active region.

11. The reader of claim 1, wherein respective first and second magnetic shields are formed with each row, the first shield and the second shield disposed to face each other with a non-magnetic material separating the first shield and the second shield and with the active and inactive regions of each respective row embedded in the non-magnetic material.

12. The reader of claim 11, wherein the thickness of the first and second magnetic shields is in the range of 0.4 to 4.0 microns.

13. The reader of claim 11, wherein the thickness of the first and second magnetic shields is between 1.0 micron and 2.0 microns.

14. The reader of claim 11, wherein the thickness of the non-magnetic material separating the first and second magnetic shields is in the range of 0.1 to 0.5 microns.

15. The reader of claim 11, wherein the thickness of the non-magnetic material separating the first and second magnetic shields is in the range of approximately two to three times a length of a shortest magnetic domain on a magnetic medium to be read.

16. The reader of claim 1, wherein the first row and the second row share a magnetic shield.

17. The reader of claim 16, wherein a thickness of the magnetic shield is in the range of 0.4 to 4.0 microns.

18. The reader of claim 16, wherein a thickness of the magnetic shield is in the range of 1.0 to 2.0 microns.

19. The reader of claim 1, wherein the first row and the second row share a magnetic shield that serves as a current conductor for active regions of the first row and the second row.

20. The reader of claim 1, further comprising a layer of magnetic shields interspersed with non-shielding material, each magnetic shield of a width at least as great as the width of the active regions plus widths of biasing magnets bracketing the active region.

21. The reader of claim 20, wherein the width of each magnetic shield is at least as great as the width of the active region plus the widths of the biasing magnets plus widths of conductors for sourcing current to and sinking current from each active region.

22. The reader of claim 1, further comprising a layer of magnetic shields, each magnetic shield for disposition in electrical contact with respective active regions of the first row, each magnetic shield separated from others by non-magnetic regions, and serving as either a current source or a current sink for the respective active regions.

23. The reader of claim 1, wherein each active region comprises one of an AMR sensor, a CIP GMR sensor, a CPP spin valve GMR sensor, and a CPP tunneling GMR sensor.

24. The reader of claim 1, wherein each active region width is about half a width of data tracks recorded on a storage medium.

25. The reader of claim 24, wherein the active region width is in the range of 0.5 to 10.0 microns.

26. The reader of claim 1, wherein active regions of each row are formed from a unitary magnetoresistive element subdivided by a plurality of voltage tabs.

27. In a reader for reading from a magnetic storage medium, a face portion of the reader for opposing a surface of the magnetic storage medium, the face portion comprising:

a plurality of active regions disposed into a plurality of adjacent rows, each row having multiple active, regions, with inactive regions separating active regions in each row, and with column-wise offsets for active regions between adjacent rows;

wherein each inactive region has a width at least approximately as great as the width of the active region multiplied by one less than the number of rows of the plurality.

28. The face portion of claim 27, further comprising at least one magnetic shield disposed between adjacent rows.

29. The reader of claim 28, wherein the at least one magnetic shield includes a magnetic shield shared between each adjacent row.

30. The reader of claim 29, wherein each shared magnetic shield serves as a conductor of electrical charge for at least two active regions.

31. The reader of claim 27, wherein the plurality of adjacent rows includes at least four rows, and no active region is column-wise nearest to any active region of an adjacent row, compared with active regions of non-adjacent rows.

32. The reader of claim 27, wherein each row includes a first permanent magnet proximate a first end of the row and a second permanent magnet proximate a second end of the row, and each active region of each row is defined by a plurality of spaced apart voltage tabs in electrical contact with a magnetoresistive element disposed between the first permanent magnet and the second permanent magnet.

33. The reader of claim 27, wherein each active region of each row shares a permanent magnet biasing element with another active region of that row.

34. The reader of claim 27, wherein each active region of each row shares at least one electrical contact with at least one other active region for conducting electrical current for both active regions.

35. A reader for magnetic storage media, comprising:

a plurality of rows of integrally formed magnetoresistive read elements, each read element of a row spaced apart from adjacent read elements of that row by at least a width of the active region multiplied by the number of rows in the plurality, and read elements of all rows of the plurality columnwise offset from each other at least by a width of an active region of the read elements.

36. The reader of claim 35, further comprising a shield for conducting electrical current for at least one of the active regions during operation of the reader.