Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
2001-01-12
2003-01-07
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
Reexamination Certificate
active
06504675
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to heads for high track density perpendicular magnetic recording, and more particularly relates to writing poles of such heads which exhibit a suppressed effect of the skew angle on the width of the recorded track.
BACKGROUND INFORMATION
Perpendicular magnetic recording systems have been developed for use in computer hard disk drives. A typical perpendicular recording head includes a trailing write pole, a leading return or opposing pole magnetically coupled to the write pole, and an electrically conductive magnetizing coil surrounding the write pole. The bottom of the opposing pole has a surface area greatly exceeding the surface area of the tip of the write pole.
Conventional perpendicular recording media typically include a hard magnetic recording layer and a soft magnetic underlayer which provide a flux path from the trailing write pole to the leading opposing pole of the writer. To write to the magnetic recording media, the recording head is separated from the magnetic recording media by a distance known as the flying height. The magnetic recording media is moved past the recording head so that the recording head follows the tracks of the magnetic recording media, with the magnetic recording media first passing under the opposing pole and then passing under the write pole. Current is passed through the coil to create magnetic flux within the write pole. The magnetic flux passes from the write pole tip, through the hard magnetic recording track, into the soft underlayer, and across to the opposing pole.
Perpendicular recording designs have the potential to support much higher linear densities than conventional longitudinal designs, especially when a bilayer perpendicular media with a soft magnetic underlayer is used. Magnetization transitions on the bilayer recording disk are recorded by a trailing edge of the trailing pole and reproduce the shape of the trailing pole projection on the media plane. However, due to the change in skew angle as the recording head travels in an arc across the disk, this can result in unwanted side writing when a rectangular shaped write pole is used.
The present invention has been developed in view of the foregoing.
SUMMARY OF THE INVENTION
An aspect of the present invention is to provide a perpendicular magnetic recording head for writing on media such as bilayer magnetic recording disks. The writer decreases the dependence of the recorded track width on the skew angle, thereby improving recording density. This is accomplished by controlling the shape of the trailing write pole at the air bearing surface (ABS). The leading edge of the write pole is narrower than the trailing edge of the write pole. In accordance with an embodiment of the invention, the pole of the writer has a trapezoidal cross-section at the ABS with a wide and flat trailing edge and tapered sides. The slope angle of the sides may be greater than or equal to the maximum skew angle of the writer during recording.
An aspect of the present invention is to provide a perpendicular magnetic recording head comprising a write pole, and means for reducing a skew effect during writing of a magnetic recording medium by the write pole.
Another aspect of the present invention is to provide a write pole of a perpendicular magnetic recording head. The write pole comprises a leading edge and a trailing edge, wherein the trailing edge is wider than the leading edge.
A further aspect of the present invention is to provide a perpendicular magnetic recording head comprising an opposing pole and a write pole. The write pole comprises a leading edge and a trailing edge, and the trailing edge is wider than the leading edge.
These and other aspects of the present invention will be more apparent from the following description.
REFERENCES:
patent: 4839761 (1989-06-01), Gatzen
patent: RE33949 (1992-06-01), Mallary et al.
patent: 5225953 (1993-07-01), Wada et al.
patent: 5495379 (1996-02-01), McNeil et al.
patent: 5995341 (1999-11-01), Tanaka et al.
Batra Sharat
Murdock Edward Stephens
Shukh Alexander M.
Stageberg Frank Edgar
Pietragallo Bosick & Gordon
Seagate Technology LLC
Towner, Esq. Alan G.
Tupper Robert S.
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