Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
2001-12-18
2004-02-24
Chen, Tianjie (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
Reexamination Certificate
active
06697221
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a perpendicular magnetic recording head for writing by applying a perpendicular magnetic field to a recording medium, such as a disk having a hard film, and to a method for making the same. More particularly, the invention relates to a perpendicular magnetic recording head which suppresses fringing in a recorded pattern and which is suitable for an increased recording density, and to a method for making the same.
2. Description of the Related Art
In a perpendicular magnetic recording apparatus, magnetic data is written in a recording medium, such as a disk, at high densities.
FIG. 27
is a sectional view which shows a general structure of a perpendicular magnetic recording head used in a perpendicular magnetic recording apparatus.
As shown in
FIG. 27
, a perpendicular magnetic recording head H is provided on a trailing edge of a slider
1
which floats above or slides over a recording medium. For example, the perpendicular magnetic recording head H is disposed between a nonmagnetic film
2
and a nonmagnetic coating film
3
on a trailing edge
1
a
of the slider
1
.
The perpendicular magnetic recording head H includes an auxiliary magnetic pole layer
4
composed of a ferromagnetic material and a main magnetic pole layer
5
composed of a ferromagnetic material formed at a distance from the auxiliary magnetic pole layer
4
. A front end
4
a
of the auxiliary magnetic pole layer
4
and a front end
5
a
of the main magnetic pole layer
5
are exposed at a surface Ha facing a recording medium Md. The auxiliary magnetic pole layer
4
and the main magnetic pole layer
5
are magnetically coupled to each other at a magnetic coupling section which is provided toward the back from the surface Ha.
A nonmagnetic insulating layer
7
composed of an inorganic material, such as Al
2
O
3
or SiO
2
, is placed between the auxiliary magnetic pole layer
4
and the main magnetic pole layer
5
. A front end
7
a
of the nonmagnetic insulating layer
7
is exposed at the surface Ha between the front end
4
a
and the front end
5
a.
A coil layer
8
composed of a conductive material, such as Cu, is embedded in the nonmagnetic insulating layer
7
.
As shown in
FIG. 27
, a thickness hw of the front end
5
a
of the main magnetic pole layer
5
is smaller than a thickness hr of the front end
4
a
of the auxiliary magnetic pole layer
4
. The width in the track width direction (in the X direction in the drawing) of the front end
5
a
of the main magnetic pole layer
5
corresponds to a track width Tw, which is sufficiently smaller than the width in the track width direction of the front end
4
a
of the auxiliary magnetic pole layer
4
.
The recording medium Md on which magnetic recording is performed by the perpendicular magnetic recording head H moves in the Y direction relative to the perpendicular magnetic recording head H. The recording medium Md is provided with a hard film Ma on the surface and with a soft film Mb inside.
When a recording magnetic field is induced to the auxiliary magnetic pole layer
4
and the main magnetic pole layer
5
by applying an electrical current to the coil layer
8
, a leakage recording magnetic field between the front end
4
a
of the auxiliary magnetic pole layer
4
and the front end
5
a
of the main magnetic pole layer
5
is transmitted through the hard film Ma perpendicularly and then passes through the soft film Mb. Since the area of the front end
5
a
of the main magnetic pole layer
5
is sufficiently smaller than the area of the front end
4
a
of the auxiliary magnetic pole layer
4
, magnetic flux &PHgr; is concentrated in the front end
5
a
of the main magnetic pole layer
5
, and magnetic data is written in the hard film Ma at the section facing the front end
5
a
by the magnetic flux &PHgr;.
FIG. 28
is a partial front view of the perpendicular magnetic recording head shown in
FIG. 27
, viewed from the surface Ha. The main magnetic pole layer
5
is formed on a plating underlayer
5
b
composed of a magnetic material by plating using a magnetic material. The main magnetic pole layer
5
has a curved upper surface
5
c
in a convex form. In the conventional perpendicular magnetic recording head, sides
5
d
of the main magnetic pole layer
5
are perpendicular to the track width direction (the X direction in the drawing).
FIG. 29
is a plan view of a recording track on a recording medium in which signals have been written by the perpendicular magnetic recording head shown in
FIGS. 27 and 28
.
When the slider
1
moves between the outside periphery and the inside periphery, a skew angle may occur in which the sides
5
d
of the main magnetic pole layer
5
are inclined relative to a tangent of moving of the recording medium Md (the Y direction). If the sides
5
d
of the main magnetic pole layer
5
are perpendicular to the track width direction, when the sides
5
d
have a skew angle relative to the tangent of moving of the recording medium Md (the Y direction), the sides
5
d
of the main magnetic pole layer
5
apply an oblique leakage magnetic field to the outside of the track width Tw
1
as illustrated by broken lines in
FIG. 29
, and fringing F is generated, resulting in a degradation in offtrack performance.
If the upper surface
5
c
of the main magnetic pole layer
5
is a curved surface in a convex form, domain boundaries B
1
are curved and the pulse width of a regenerated waveform is increased. As a result, if the recording density is increased, it is not possible to obtain a clear distribution of recording magnetization. Therefore, it becomes difficult to increase the recording density in the longitudinal direction of the recording track (in the A direction).
SUMMARY OF THE INVENTION
Objects of the present invention are to provide a perpendicular magnetic recording head which can suppress fringing in a recorded pattern, which can improve the offtrack performance, and which can improve the recording density in the longitudinal direction of a recording track, and to provide a method for making the same.
In one aspect of the present invention, a perpendicular magnetic recording head includes an auxiliary magnetic pole layer exposed at a surface facing a recording medium; a main magnetic pole layer exposed at the surface facing the recording medium, the main magnetic pole layer being deposited on the auxiliary magnetic pole layer with an insulating layer therebetween; a coil layer for applying a recording magnetic field to the auxiliary magnetic pole layer and the main magnetic pole layer, the coil layer being provided toward the back from the surface facing the recording medium, wherein magnetic data is written in the recording medium by the magnetic field concentrating in the main magnetic pole layer perpendicular to the plane of the recording medium; and a connecting layer placed on the auxiliary magnetic pole layer toward the back from the surface facing the recording medium, the main magnetic pole layer and the connecting layer being magnetically coupled to each other directly or by a yoke layer formed on the main magnetic pole layer and on the connecting layer. At the surface facing the recording medium, the upper base of the main magnetic pole layer is wider than the lower base at the auxiliary magnetic pole layer side of the main magnetic pole layer so that the width in the track width direction of the main magnetic pole layer gradually increases with distance from the auxiliary magnetic pole layer.
In the present invention, at the surface facing the recording medium, the upper base of the main magnetic pole layer is wider than the lower base of the main magnetic pole layer so that the width in the track width direction of the main magnetic pole layer gradually increases with distance from the auxiliary magnetic pole layer. That is, at the surface facing the recording medium, the main magnetic pole layer has a substantially inverted trapezoidal front end.
Consequently, when writing is performed on the recording medium, even if t
Gochou Hideki
Kobayashi Kiyoshi
Koyama Akira
Sato Kiyoshi
Watanabe Toshinori
Alps Electronic Co., Ltd.
Brinks Hofer Gilson & Lione
Chen Tianjie
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