JPH04103012A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To improve the characteristic by specifying an angle made against the magnetic gap length direction and selecting other end edges of each opposite side in parallel. CONSTITUTION:When the magnetic gap length direction, and the direction vertical to the magnetic gap length, that is, the track width direction are set as the X direction and the Y direction, respectively, an axis of easy magnetization becomes the Y direction. Accordingly, even in the case of narrow track width, magnetization of a thin film magnetic core 2 in the magnetic gap responds linearly to a magnetic flux which is led in from the magnetic gap 1 at the time of reproduction. Also, it is suppressed that a noise caused by a movement of a magnetic wall, what is called a Barkhausen noise is generated in a reproducing waveform, and magnetic permeability in the vicinity of the magnetic gap,k that is, in the tip part of the thin film magnetic core 2 is deteriorated. In such a way, a sufficient reproducing output can be obtained, and the characteristic can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head, particularly a horizontal so-called planar thin film magnetic head.

[Summary of the invention]

The present invention relates to a thin-film magnetic head, which has a thin-film magnetic core having a magnetic gap arranged substantially parallel to a magnetic recording medium, and the thin-film magnetic core has a track width determined by the width of both end faces facing each other across the magnetic gap. The angle θ formed between one end edge on opposite sides and the magnetic gap length direction of the magnetic gap is 30″≦θ≦80＠, and The other edge is selected to be approximately parallel to the length direction of the magnetic gap, thereby improving the reproduction output by avoiding a decrease in magnetic permeability near the magnetic gap in the thin film magnetic head for narrow track reproduction. To avoid crosstalk in the track, achieve low noise, high quality playback, and improve characteristics.

[Conventional technology]

A conventional horizontal so-called planar type thin-film magnetic head is shown in FIGS. 6 to 8. FIG. 6 is a perspective view of a magnetic head slider, and FIG. 7 is an enlarged cross-sectional view of the thin-film magnetic head in the track width direction. , FIG. 8 is an enlarged perspective view of the magnetic gap of the thin film magnetic head.

As shown in FIG. 6, the magnetic head slider (30)
A groove (32) extending in the running direction is provided on the surface of the base (31) facing the magnetic recording medium, and this groove (32) allows a rail-shaped ABS (Air Bearing) to be formed.
5 surface) surface (31) is constructed. An inclined surface (34) is provided on the rear side of the ABS surface (31) with respect to the traveling direction, so that the magnetic recording medium can fly smoothly over the magnetic recording medium. For example, a Brenna type thin film magnetic head (20) is formed on a magnetic head slider (30) on the front side of the ABS surface (31) with respect to the running direction.

As shown in FIG. 7, this thin-film magnetic head has a base (3
1) Formed on top. (52) is a through hole, (53
) is a thin film magnetic core made of magnetic material such as permalloy, (
54) is a conductive layer, (55) is an insulating layer, (56) is a coil, (57) is a covering layer forming part of the good ABS surface (11), and (58) is a magnetic gap.

The magnetic gap (58) of such a thin film magnetic core (53)
), as shown in a perspective view in FIG. 8, is formed in a widening shape in which the width gradually increases in the track width direction as it moves away from the magnetic gap (58), and constitutes the magnetic gap (58). The thin film magnetic core (53) has a belt-shaped throat part (59) with a constant width.
is formed, and the width of this throat portion (59) becomes the track width TN. (56) is a coil.

The conventional track width T- is approximately 10μ, and near such a magnetic gap (58), as shown in FIG. 9A, the magnetic domain (60) has a closed domain structure with an axis of easy magnetization in the track width direction. It operates by magnetization rotation and has a linear response to the magnetic flux flowing in from the magnetic gap.

On the other hand, in recent years, efforts have been made to make magnetic recording media narrower in order to increase recording density. Therefore, in the Brehner type thin film magnetic head as described above, the track width T- is less than 10 μm, for example, about 5 μm. In this way, when the trunk width becomes small, the shape anisotropy becomes large, and the structure of the magnetic domain (60) near the magnetic gap (58) is such that the magnetization is oriented in the track width direction (and the static magnetic energy becomes large). Therefore, as shown in Figure 9B, the throat part (5
9), a closed magnetic domain structure having an axis of easy magnetization in a direction perpendicular to the track width direction is obtained. Therefore, during reproduction, the domain wall of the thin film magnetic core (53) near the magnetic gap moves with hysteresis to the magnetic flux introduced from the magnetic Guyang (58), resulting in a nonlinear response.

Therefore, noise due to domain wall movement, so-called Barkhausen noise, may occur in the reproduced waveform, and the magnetic permeability near the magnetic gap (58), that is, at the tip of the thin-film magnetic core (53) may decrease, making it difficult to obtain sufficient reproduction output. become unable.

In order to suppress such rotation in the direction of the axis of easy magnetization at the throat part (59), a structure of the magnetic gap (53) without the throat part (59) has been proposed as shown in FIG. . In this case, since the thin film magnetic core (53) is configured to gradually widen from the part that constitutes the magnetic gap (58), the track width T- is the width of the thin film magnetic core (53) at the magnetic gap (58). determined by the width of In this case, even if the track width T- is approximately 10 μ- or less, the axis of easy magnetization of the magnetic domain (60) will be parallel to the track width direction, and the magnetization will have a linear response, resulting in the above-mentioned problems such as a decrease in reproduction output. can be avoided. However, as shown by A-A in the figure, an apparent magnetic gap is formed between the thin film magnetic cores (53) in a region away from the magnetic gap (58) component, and here, there is crosstalk between adjacent ones or off-track. There was a problem that crosstalk occurred.

In the above example, a Brenna-type thin-film magnetic head was described, but in addition to the above-mentioned wire-wound magnetic head that picks up magnetic flux with a wire-wound coil, it is also possible to use a magnetoresistive element, a so-called MR element, provided under the magnetic core and use this as a magnetic sensing part. Similarly, the magnetoresistive magnetic head used also has problems such as noise generation and decreased magnetic permeability due to the narrower track axis described above.

[Problem to be solved by the invention]

The present invention aims to improve the characteristics of a narrow track width magnetic head by solving the above-mentioned problems such as nonlinear response, noise generation, and reduction in reproduction output due to movement of the axis of easy magnetization due to the narrowing of the track width.

[Means to solve the problem]

FIG. 1 shows an enlarged top view of essential parts of an example of a magnetic head according to the present invention.

As shown in FIG. 1, the present invention has a thin film magnetic core (2) having a magnetic gap (1) arranged almost parallel to a magnetic recording medium, and this thin film magnetic core (2) has a magnetic gap ( The track width is regulated by the width T- of both end surfaces (3) facing each other with the magnetic gap (1) in between, and the track width is gradually widened in the direction away from the magnetic gap (1). ) and the magnetic gap length direction of the magnetic gap (1), the angle θ is 30°≦θ≦80°,
The other opposite edges (4B) and (5B) are selected to be substantially parallel to the longitudinal direction of the magnetic gap.

[Effect]

As described above, according to the thin film magnetic head according to the present invention, the shape of the thin film magnetic core (2) is such that the throat portion is not provided;
The track width is regulated by the width of both end surfaces (3) facing each other across the magnetic gap (1), and
The width gradually increases in the direction away from the center. Therefore, for example, even if the 20 width T- is about 10 μ- or less, the magnetic domain structure is such that the magnetic gap length direction is the X direction, and the track width is perpendicular to the magnetic gap length, as shown in the top view of FIG. When the direction is the X direction, the axis of easy magnetization is the X direction.

Therefore, even with such a narrow track width, the magnetization of the thin film magnetic core (2) near the magnetic gap will respond linearly to the magnetic flux introduced from the magnetic gap (1) during reproduction, and the reproduction waveform will be affected by domain wall movement. It is possible to obtain a sufficient reproduction output by suppressing the occurrence of accompanying noise, so-called Barkhausen noise, and a decrease in magnetic permeability near the magnetic gap (1), that is, at the tip of the thin film magnetic core (2).

In addition, the throat part is eliminated and the magnetic gap (1)
The shape of the thin film magnetic core (2) constituting the thin film magnetic core (2) facing each other is determined in the magnetic gap length direction of the opposite end edge (48) and (5A) of the magnetic gap (1), that is, X The other edges (4B) and (5B) on opposite sides are
The track width T-
Even if it is about 10 μm or less, as shown by line AA in Fig. 1, in the region away from the magnetic gap (1) component,
Since no magnetic gap is formed by the opposing thin film magnetic cores (2), it is possible to avoid the occurrence of adjacent crosstalk or off-track crosstalk, achieve low noise, high quality reproduction, and improve characteristics. .

〔Example〕

Hereinafter, an example of a thin film magnetic head according to the present invention will be described in detail with reference to FIGS. 1 to 5. FIG. 3 is an enlarged cross-sectional view along line B-B of the thin-film magnetic head shown in FIG.
The figure is a side view of an example of an MR element, and FIG. 5 is a cross-sectional view showing the reproduction state of a thin-film magnetic head. In FIGS. 3 to 5, parts corresponding to those in FIG. .

In this case, in an example of a yoke-type brainer MR head equipped with an MR element, as shown in FIG.
A) and a lower yoke (2B), and an upper yoke (2B).
A coil (8) is provided between the upper yoke (2A) and the lower yoke (2B), and the upper yoke (2A) is, for example, gradually inclined toward the side facing the magnetic recording medium, that is, the ABS surface (11). A configuration is adopted in which the portion constituting the gap (1) is formed on the same plane as the surface facing the magnetic recording medium, that is, the ABS surface (11). An MR element (6) is arranged below the magnetic gap (1), and a bias magnetic field generating conductor ( 7) is formed. (12) is an insulating layer made of SiO2 or the like.

A method for forming such a thin film magnetic head is, for example, Alt.
os・TiC, CaTi01. Ferrite ceramic.

A lower yoke (2B) is formed on an insulating substrate (21) made of crystallized glass or the like by, for example, so-called frame plating, and on top of this, an insulating layer (12) made of 5ift or the like is interposed, and then a conductive layer of Cu or the like is further formed. A coil consisting of a thin film pattern (
8), and an insulating layer (12) made of Sing or the like is deposited over the entire surface of the coil (8). Then, a hole is made in the insulating layer (12) by, for example, RIE (reactive ion etching), and a magnetic material such as N1ce is filled in the hole to connect the lower yoke (2B) and the upper yoke (2A), which will be described later. (2C) and further insulation 11
(12), a bias magnetic field generating conductor (7) made of Cu or the like, and an MR element (6) via an insulating layer (12).
is formed by pattern etching using photolithography.

This MR element (6) has a structure made of two layers of NiFe with a film thickness of about 300 layers, as shown in a linear side view in FIG. The first and second MR thin II (6A) and (6B) are 5i of about 30 people, for example, where magnetostatic coupling occurs with each other but almost no exchange interaction occurs.
It is constructed by laminating layers with a nonmagnetic layer (14) made of Ot interposed therebetween.

As shown in Fig. 3, a bias magnetic field generating conductor m
After depositing a thick insulating layer (12) over the MR element (6), the insulating layer (12) is taper-etched so as to taper toward the magnetic gap forming portion, and then the magnetic gap (1) is formed. Anisotropic etching is performed leaving the insulating layer (12) in the part, and the NiF in the connection part (2C) is etched.
After connecting to the e layer and depositing NiFe or the like by plating or the like, the upper yoke (2A) is formed by patterning into a desired pattern. S again on the upper yoke (2A)
After a protective film of an insulating layer (12) made of iO□ or the like is deposited, the surface is polished to form an ABS surface (11) to obtain a thin film magnetic head (20).

In such a configuration, as shown in Figure 1,
The width of both end faces (3) of the thin film magnetic core (2) facing each other across the magnetic gear amplifier (1), that is, the track width T-, is 5 μ-.
And so. In addition, the thin film magnetic core (2) has a magnetic gear knob (
1), and is formed to gradually become wider in the direction away from the edge (4A) and (5A) on opposite sides, magnetic gear, knob (
1) The angle θ formed with the gap length direction, that is, the X direction, is approximately 4.
5°, and the other opposite edges (5A) and (5B
) was formed substantially parallel to the longitudinal direction of the magnetic gear.

Further, an MR element (6) is placed under the magnetic gap (1) in the X direction, and a bias magnetic field generating conductor (7) is placed under the MR element (6) perpendicularly thereto, that is, in the X direction. Deploy. In this case, one end edge (4A) and (5A) on the opposite sides of the upper yoke (2A) are set at 45 degrees with respect to the X direction, so the total angle is 45 degrees clockwise from the
Since the upper yoke (2A) is formed to extend in the diagonal direction rotated by 5 degrees, the upper yoke (2A) is
The lower yoke (2B) was formed along the tilted direction.

In this case, even if the track width Tw is about 5 μm, the thin film magnetic core (2) constituting the magnetic gap (1) is formed substantially wide, so that its magnetic domain structure is The easy axis can be set in the track width direction, that is, the X direction, and it is possible to avoid a decrease in magnetic permeability and obtain a good reproduction output.

In addition, in the off-trunk region shown by line A-A in FIG. 1, one side of the upper yoke (2A) is formed almost parallel to the magnetic gear knob length direction, that is, the X direction, that is, it is configured with only one side. Since no gap is formed in this case, it is possible to avoid inter-adjacent cross-over and off-track space talk.

Furthermore, in the MR element (6) as described above, if one side of the upper yoke (2A) that serves as a shield is missing in the off-track region, there is a possibility that the shielding effect here may be lost. , in practice,
Since the magnetic flux due to the off-track signal is applied to the MR element (6) in the direction of its axis of easy magnetization, this signal is hardly reproduced.

That is, as shown in a cross-sectional view in FIG.
At a position other than directly above the MR element (6
) flows in the direction of the difficult axis, a reproduced signal is obtained.

In the above example, the upper yoke (
28), one end edge (48) on the opposite side and (
5A) and the X direction was set to 45'', but it was confirmed that when this angle θ is 30°≦θ≦80@, almost no problematic crosstalk occurs. Although the edges (4B) and (5B) are substantially parallel to the X direction, they may be formed at some angle to the X direction as long as the above-mentioned crosstalk problem does not occur.

Further, in the above example, the thin film magnetic core (2) is made of Ni.
Although it is a Fe-plated film, other FeCoNi-plated films,
NiFe sputtered film, FeAZSi sputtered film, etc., other Fe-based sputtered films, CoZrNb, CoZrT
An amorphous magnetic film such as a may also be used. For the recording coil (8) and the bias magnetic field generating conductor (7), in addition to Cu, a sputtered film such as AZ or a plating film may be used.

Furthermore, although the above example is applied to a yoke-type planar thin-film magnetic head using an MR element, the structure of the present invention can also be applied to other so-called thin-film magnetic heads that perform recording and reproduction using wire-wound coils. Can be applied.

〔Effect of the invention〕

As described above, according to the thin-film magnetic head according to the present invention, the shape of the I-film magnetic core (2) is such that the throat portion is not provided;
The track width is regulated by the width of both end surfaces (3) facing each other across the magnetic gap (1), and
The width gradually increases in the direction away from the center. Therefore, for example, even if this width T- is about 10 μ- or less, the structure of the magnetic domain is such that the magnetic gap length direction is the X direction and the magnetic gap length is perpendicular to the When the width direction is the Y direction, the axis of easy magnetization is the Y direction. Therefore, even with such a narrow track width, the magnetization of the thin film magnetic core (2) near the magnetic gap will respond linearly to the magnetic flux introduced from the magnetic gap (1) during reproduction, and the reproduction waveform will be affected by domain wall movement. Accompanying noise, so-called Barkhausen noise, may occur, or the magnetic gap (1
) It is possible to suppress the decrease in magnetic permeability in the vicinity of the thin film magnetic core (2), that is, at the tip of the thin film magnetic core (2), and to obtain sufficient reproduction output.

In addition, the throat part is eliminated and the magnetic gear knob (1)
The shape of the thin film magnetic core (2) constituting the magnetic gap (1) is such that the angle θ formed by the opposite end edges (4A) and (5A) and the magnetic gap length direction, that is, the X direction of the magnetic gap (1) is 30°≦
By setting θ≦80° and selecting the other edges (4B) and (5B) on opposite sides to be approximately parallel to the X direction,
Even if the track width T- is less than lOp, as shown by line A-A in Fig. 1, the opposing thin film magnetic core (2) is not formed in the area away from the magnetic gap (1) component. , it is possible to avoid the occurrence of adjacent crosstalk or off-track crosstalk, achieve low noise, high quality reproduction, and improve characteristics.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of the main parts of the thin-film magnetic head according to the present invention, FIG. 2 is a top view showing the magnetic domain structure in the magnetic gap of the thin-film magnetic head according to the present invention, and FIG. 3 is an example of the thin-film magnetic head. The fourth part is a cross-sectional view showing an example of an MR element, the fifth part is a cross-sectional view showing how a thin film magnetic head is regenerated, the sixth part is a perspective view showing a magnetic head slider, and the fourth part is a cross-sectional view showing an example of an MR element. Figure 7 is a cross-sectional view showing a thin film magnetic head;
9 is a perspective view showing a conventional magnetic gap, FIG. 9 is a top view showing the magnetic domain structure in the magnetic gap of a conventional thin film magnetic head, and FIG. 10 is a top view showing another example of the conventional magnetic gap. (1) is a magnetic gap, (2) is a thin film magnetic core, (2A
) is the upper yoke, (2B) is the lower yoke, (3) is the end surface, (4A), (4B), (5A) and (5B) are the edges,
(6) is an MR element, (7) is a conductor for generating a bias magnetic field,
(8) is a coil, (10) is a magnetic domain, (11) is an ABS surface, (12) is an insulating layer, (14) is a non-magnetic layer, (15) is a magnetic recording medium, (16) is a magnetization transition part, (20) is a thin film magnetic head.

Claims (1)

[Claims] A thin film magnetic core having a magnetic gap arranged substantially parallel to a magnetic recording medium, the track width of the thin film magnetic core being regulated by the width of both end faces facing each other across the magnetic gap. The angle θ formed by one end edge on opposite sides and the magnetic gap length direction of the magnetic gap is 30°≦θ≦80°, and the opposite sides The other edge of the thin film magnetic head is selected to be substantially parallel to the longitudinal direction of the magnetic gap.