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Magnetic Recording Head, Write Structure with Chamfered Top-Pole, Top Corners to Reduce Adjacent Track Interference and Method of Making the Same

IP.com Disclosure Number: IPCOM000014740D
Original Publication Date: 2000-Dec-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Abstract

Described is a magnetic recording head write structure that mitigates spurious flux that emanates from the top corners of P2 which causes information on adjacent tracks to be degraded. By chamfering the top corners of P2, these spurious fringing fields emanating from the top corners of P2 that are responsible for adjacent track interference are thereby reduced. Also, described are methods for making a magnetic recording head write structure incorporating the chamfered P2 top corners. It is known that fabricating a P2 layer with a large P2 thickness (P2T) dimension has advantages for over-write performance of a write head, but it also can cause "side-writing" which results from the top corners of the P2 flying over adjacent written tracks when the head is skewed, as it must be when accessing tracks at the OD and ID of a magnetic recording disk. This "side-writing" is due to spurious flux density emanating from the top corner of the P2 on one side of the written track which results in the "over-writing" of information on adjacent tracks and appears as an overall degradation of amplitude of the read-back signal from a track adjacent to a track which was previously written. As a consequence, the written track windage must be increased to prevent the fields from the top corners of the P2 from interfering with adjacent tracks, and consequently this limits areal density. A preferred, first embodiment of the invention comprises a magnetic recording head write structure having a write head element with a bottom pole (P1) separated from a top pole (P2) by a write gap (G3); the corners at a top of the P2 are chamfered to have a circular shape having a radius of curvature sufficiently large to lower a fringing field below a level whereby a recording medium can be written. A second embodiment comprises a magnetic recording head write structure as described above wherein the corners at a top of the P2 are chamfered simply by breaking the corners along a line that cuts a triangular portion of a corner away to lower a fringing field below a level whereby a recording medium can be written. A third embodiment comprises a magnetic recording head write structure as described above wherein the corners at a top of the P2 are chamfered by breaking the corners along a line that cuts a triangular portion of a corner away, and repeating a process of breaking corners created in a previous step so as to approximate a rounded corner with an inscribed circle having a radius of curvature sufficiently large to lower a fringing field below a level whereby a recording medium can be written. A preferred embodiment for making the same comprises a method for producing the structure of the first embodiment above by use of ion-milling at wafer level to produce a P2 shape with chamfered top corner edges. Another embodiment for making the same comprises a method for producing the structure of the second and third embodiments above by use of focused ion beam (FIB) milling at row or head level to remove triangular portions at both corners. These embodiments should not be construed to preclude such embodiments as ion-milling at row level through a photoresist mask disposed and shaped to allow milling away the P2 top corners or other similar embodiments which would be obvious to those skilled in the art.

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  Magnetic Recording Head, Write Structure with Chamfered Top-Pole, Top Corners to Reduce Adjacent Track Interference and Method of Making the Same

   Described is a magnetic recording head write structure that mitigates spurious flux that emanates from the top corners of P2 which causes information on adjacent tracks to be degraded. By chamfering the top corners of P2, these spurious fringing fields emanating from the top corners of P2 that are responsible for adjacent track interference are thereby reduced. Also, described are methods for making a magnetic recording head write structure incorporating the chamfered P2 top corners.

    It is known that fabricating a P2 layer with a large P2 thickness (P2T) dimension has advantages for over-write performance of a write head, but it also can cause "side-writing" which results from the top corners of the P2 flying over adjacent written tracks when the head is skewed, as it must be when accessing tracks at the OD and ID of a magnetic recording disk. This "side-writing" is due to spurious flux density emanating from the top corner of the P2 on one side of the written track which results in the "over-writing" of information on adjacent tracks and appears as an overall degradation of amplitude of the read-back signal from a track adjacent to a track which was previously written. As a consequence, the written track windage must be increased to prevent the fields from the top corners of the P2 from interfering with adjacent tracks, and consequently this limits areal density.

   A preferred, first embodiment of the invention comprises a magnetic recording head write structure having a write head element with a bottom pole (P1) separated from a top pole (P2) by a write gap (G3); the corners at a top of the P2 are...