Thin film magnetic head

Details Thin film magnetic head Thin film magnetic head

1998-04-22

2001-02-13

Miller, Brian E. (Department: 2754)

Dynamic magnetic information storage or retrieval

Head

Core

Reexamination Certificate

active

06188543

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a thin film magnetic head with a recording track width capable of higher recording density in magnetic media such as magnetic disks.
DESCRIPTION OF THE RELATED ART
Due to the recent demand for higher recording density in the magnetic media, the recording track width of the thin film magnetic head is becoming increasingly narrower. In the near future, a thin film head with a recording track width of a submicron (equal to or less than one micrometer) order will be certainly requested.
In general, magnetic pole layers in a thin film magnetic recording head are made of polycrystal magnetic material such as NiFe. This polycrystalline substance includes many micro monocrystal substances with various crystal orientations. Therefore, if the recording track width is wide enough in comparison with the size of the each monocrystal substance, magnetic characteristics of the recording head will not be influenced by the crystal orientation of each monocrystal substance.
However, when the recording track width is of a submicron order, the size of the monocrystal magnetic substance cannot be negligible. Namely, the magnetic characteristics of the recording head will be greatly influenced by the magnetization direction due to the crystal orientation of each monocrystal magnetic substance and thus variations in the recording capability of the head will occur.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a thin film magnetic head, whereby a stable recording capability can be realized even when its recording track width is very narrow.
The present invention relates to a thin film magnetic head including a recording gap layer, and lower and upper magnetic pole layers made of polycrystalline magnetic substances, deposited to sandwich the recording gap layer. Particularly, according to the present invention, an average particle size D of crystal substances in a least a region of the upper magnetic pole layer, near the recording gap layer with respect to a recording track width W is set to D≦W/20.
The average particle size D in the magnetic pole portion which actually concerns the magnetic recording operation becomes smaller in accordance with the narrowing of the recording track width W, and thus the number of crystals aligned between the track width will not be so small. As a result, variations in the magnetic characteristics due to the crystal orientation of each monocrystal magnetic substance can be dispersed, and thus variations in the recording capability of the head can be prevented from occurring.
In one embodiment, an average particle size D of crystal substances in at least a region of the lower magnetic pole layer, near the recording gap layer with respect to the recording track width W also may be set to D≦W/20.
In another embodiment, an average particle size D of crystal substances only in a region of the upper magnetic pole layer, near the recording gap layer with respect to a recording track width W may be set to D≦W/20. In a further embodiment, an average particle size D of crystal substances in all regions of the upper magnetic pole layer with respect to the recording track width W may be set to D≦W/20.
An average particle size D of crystal substances in all regions of the lower magnetic pole layer with respect to the recording track width W may be set to D≦W/20.
In most cases, the recording track width W is set to W≦1.5 &mgr;m.
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: 5585984 (1996-12-01), Hasegawa et al.
patent: 62-287410 (1987-12-01), None
patent: 3-109703 (1991-05-01), None
patent: 8-3883 (1996-01-01), None

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