Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
1998-05-21
2001-01-23
Ometz, David L. (Department: 2754)
Dynamic magnetic information storage or retrieval
Head
Core
C360S119050
Reexamination Certificate
active
06178065
ABSTRACT:
FIELD INVENTION
The present invention relates to a thin film magnetic head such as a composite type thin film magnetic head formed by integrating both an inductive recording head part for recoding information on a magnetic medium such as a magnetic disk and a magnetoresistive effect (MR) reproducing head part for reproducing the information, and to a manufacturing method of the head.
DESCRIPTION OF THE RELATED ART
A thin film magnetic recording head has in general a multi-layered structure of a lower magnetic pole layer, a recording gap layer and an upper magnetic pole layer. The recording gap layer is sandwiched between the lower and upper pole layers. Opposed edges in an ABS (Air Bearing Surface) plane of these lower and upper pole layers define a recording track width of the head.
In such a recording head, if lengths of the opposed edges in the ABS plane of the lower and upper poles are significantly different with each other, a great deal of side fringe magnetic flux (leakage flux being leaked from ends of respective edges of the poles and extending in the track width directions) will be produced during recording. Particularly, in the composite type thin film magnetic head with both the inductive recording head part and the MR reproducing head part, since the length of the opposed edge of the lower magnetic pole which also shares a shield layer of the MR head part is inevitably longer than that of the upper magnetic pole, large amounts of side fringe magnetic flux will be necessarily produced.
The side fringe magnetic flux will induce an effective increase of the recording track width so called as “recording effusion”. Especially, in the recent recording head with a narrower recording track width due to the demand for higher recording density, this “recording effusion” causes many problems such as for example crosstalk between the adjacent tracks and deletion of magnetic patterns recorded on the adjacent tracks to occur.
In order to reduce the production of “recording effusion” in the composite type thin film magnetic head, there are known technologies in which the ABS shape of the lower magnetic pole is formed as a plane protrusion shape to coincide the length of the edge of the lower pole with the length of the opposed edge in the ABS plane of the upper pole (Japanese patent unexamined publication Nos. 7(1995)-220245, 7(1995)-225917, 7(1995)-262519 and 7(1995)-296331 for example). However, even if the pole shape is formed so that the lengths of the opposed edges in the ABS plane of the lower and upper poles coincide with each other, some side fringe magnetic flux is produced causing the problems of “recording effusion” to still occur.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a thin film magnetic head and a manufacturing method of the head, whereby effective increase of the recording track width due to side fringe magnetic flux can be substantially prevented.
According to the present invention, a thin film magnetic head has a recording gap layer made of a nonmagnetic material, lower and upper magnetic pole layers made of a magnetic material, the lower and upper magnetic pole layers sandwiching the recording gap layer, and a magnetic material side layer deposited via a nonmagnetic material side layer on at least a part of a side surface of at least the upper magnetic pole layer.
Thus, most of leakage flux produced at both ends of the edge of the upper magnetic pole layer passes through the nonmagnetic material side layer and is applied to the magnetic material side layer. Therefore, the side fringe magnetic flux leaked from the recording head is extremely reduced. As a result, effective increase of the recording track width due to the side fringe magnetic flux can be nearly prevented.
It is preferred that the nonmagnetic material side layer has a thickness thinner than that of the recording gap layer.
It is also preferred that the nonmagnetic material side layer is made of redeposited nonmagnetic material which is used to form the recording gap layer.
It is further preferred that the magnetic material side layer is made of redeposited magnetic material which is used to form the lower magnetic pole layer.
The upper magnetic pole layer may be constituted by a single magnetic material layer, or constituted by a plurality of stacked magnetic material layers.
It is preferred that the upper magnetic pole layer is constituted by a plurality of stacked magnetic material layers, and that the nonmagnetic material side layer is deposited on a side surface of the upper magnetic pole layer via a layer made of redeposited magnetic material which is used to form a partial layer of the upper magnetic pole layer.
According to the present invention, also, a method for manufacturing a thin film magnetic head includes a step of depositing a nonmagnetic material layer for a recording gap layer on a first magnetic layer for a lower magnetic pole layer, a step of forming an upper magnetic pole layer constituted by a second magnetic material layer on the nonmagnetic material layer, and a step of forming the lower magnetic pole layer and the recording gap layer by ion milling to remove a part of the nonmagnetic material layer and a part of the first magnetic material layer so that a part of the removed material of the nonmagnetic material layer and a part of the removed material of the first magnetic material layer are redeposited on a side surface of the upper magnetic pole layer, respectively.
Since the nonmagnetic material side layer and the magnetic material side layer used to greatly reduce the side fringe magnetic flux are made of redeposited materials which are necessarily generated in the ion milling processes for forming the lower magnetic pole layer and the recording gap layer, no additional process is needed for forming this structure. Furthermore, since the redeposited materials are utilized as they are without adding a process for preventing the removed material to redeposit or without adding a process for removing the redeposited material, the manufacturing processes can be simplified.
The upper magnetic pole layer forming step may include a step of forming the upper magnetic pole layer by a single magnetic material layer or by a plurality of stacked magnetic material layers.
According to the present invention furthermore, a method for manufacturing a thin film magnetic head includes a step of depositing a nonmagnetic material layer for a recording gap layer on a first magnetic layer for a lower magnetic pole layer, a step of depositing a second magnetic material layer for a lower part layer of an upper magnetic pole layer on the nonmagnetic layer, a step of forming an upper part layer of the upper magnetic pole layer on the second magnetic material layer, the upper part layer being constituted by a third magnetic material layer, and a step of forming the lower magnetic pole layer, the recording gap layer and the lower part layer of the upper magnetic pole layer by ion milling to remove a part of the second magnetic layer, a part of the nonmagnetic material layer and a part of the first magnetic material layer so that a part of the removed material of the second magnetic material layer, a part of the removed material of the nonmagnetic material layer and a part of the removed material of the first magnetic material layer are redeposited on a side surface of the upper magnetic pole layer, respectively.
It is preferred that the ion milling is executed using a downward beam of ions directed substantially normal to a surface of the nonmagnetic material layer.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
REFERENCES:
patent: 5438747 (1995-08-01), Krounbi et al.
patent: 5452164 (1995-09-01), Cole et al.
patent: 5751526 (1998-05-01), Schemmel
patent: 5761014 (1998-06-01), Urai et al.
patent: 5774308 (1998-06-01), Ohtsuka et al.
patent: 5805392 (1998-09-01), Mallary et al.
patent: 5916423 (1999-06
Matsukuma Koji
Mino Tetsuya
Terunuma Koichi
Uno Yasufumi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Ometz David L.
TDK Corporation
LandOfFree
Thin film magnetic head and manufacturing method of the head does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thin film magnetic head and manufacturing method of the head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin film magnetic head and manufacturing method of the head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2519362