JPH06243436A - Magnetoresistive effect type magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of crosstalk noises by turning back and forming wiring conductors in order to cancel the currents induced by the conpling of signal magnetic fluxes from adjacent tracks with the wiring conductors with each other. CONSTITUTION:The wiring conductor 2 provided on an ABS surface 7 side of an MR element 4 is formed to a planar rectangular shape in such a manner that the one end thereof faces the surface 7. This conductor is connected to a shielding magnetic material 6 of an upper layer. On the other hand, the wiring conductor 3 provided on the rear end side is formed by turning back a band- shaped conductor pattern and is connected to the grounding part of the element 4. Namely, the conductor 3 is spirally formed by a first conductor part 3a provided in lamination on the rear end of the element 4 so as to intersect perpendicularly with the element 4, a second conductor part 3b provided in the central part in the longitudinal direction of the element 4 parallel therewith, a third conductor part 3c provided behind 3a, a first connecting part 3d connecting 3a and 3b, a second connecting part 3e connecting 3a, 3b and 3c and a third connecting part 3f connecting 3c and the grounding part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resistance effect type magnetic head suitable for reading an information signal recorded on a hard disk, for example.

[0002]

2. Description of the Related Art For example, a read-only magnetic head mounted on a hard disk drive device or the like has excellent short wavelength sensitivity. A magnetoresistive effect magnetic head (hereinafter referred to as an MR head) is generally used.

As shown in FIG. 8, for example, such an MR head has a magnetoresistive effect element (hereinafter referred to as an MR element) 10 on a substrate 101 made of a non-magnetic material which serves as a slider.
2 is the sliding surface (hereinafter,
It is called the ABS surface. ) 101a is arranged in parallel. Then, the wiring conductors 103 and 104 are drawn out from both ends of the MR element 102, and are sandwiched from above and below by a pair of shield magnetic bodies 105 (upper shield magnetic bodies are not shown). Composed.

In the so-called lateral MR head in which the MR element 102 is arranged in parallel with the ABS 101a,
One side edge of the element 102 in the longitudinal direction is the ABS surface 101.
It is provided so as to be exposed to a. The wiring conductors 103 and 104 connected to the MR element 102 are also provided so that one side edge thereof is exposed to the ABS surface 101a.

However, in the MR head having such a structure, the wiring system including the MR element 102 and the wiring conductor 103 serves as a one-turn coil, and an induced current is generated by the magnetic flux passing through the upper and lower shield magnetic bodies 105. The induced current at this time becomes crosstalk noise, which deteriorates off-track characteristics and hinders improvement in track density. Therefore, even if the MR element is sandwiched by the shield magnetic body 105 in order to increase the linear recording density, the improvement of the track density is hindered.

The mechanism of crosstalk noise is that when the shield magnetic body 105 picks up a signal magnetic flux from an adjacent track and the magnetic flux flows to the shield magnetic body on the other side, the wiring conductor 10 arranged in the shield magnetic body 105.
Induced currents i ₁ , i ₂ due to the magnetic flux crossing 3, 104
Occurs. The induced currents i ₁ and i ₂ cause noise.

Therefore, in order to improve the off-track characteristic, the MR element 10 as shown in FIGS. 9 and 10, for example.
6 is arranged such that its longitudinal direction is perpendicular to the ABS surface 107, and one end of the wiring conductor 108 on the tip side of the wiring conductors 108, 109 drawn from both ends of the MR element 106 is The wiring conductor 109 on the rear end side is exposed on the ABS surface 107, is formed in the head inward direction away from the ABS surface 107, and the wiring pattern is rectangular so as to form a closed circuit. Note that the longitudinal direction of the MR element 106 is A
Even in a so-called vertical head arranged perpendicularly to the BS surface 107, the MR element 106 is sandwiched by a pair of shield magnetic bodies 110 and 111 in order to increase the linear recording density.

In this way, the induced currents i ₃ and i ₄ generated in the same direction when the signal magnetic fluxes from the adjacent tracks intersect with the wiring conductor 109 have a rectangular pattern in which the wiring conductor 109 forms a closed circuit. Since they are formed as one, they are mutually canceled and the generation of crosstalk noise is prevented. As a result, off-track characteristics are improved.

However, although the off-track characteristic can be improved by adopting such a configuration, the bias conductor 113 for applying a bias magnetic field to the MR element 106 is M-shaped.
Since it is necessary to provide the element orthogonal to the R element 106, the number of terminals increases. An increase in the number of terminals requires securing a sufficient head forming space on the substrate 112, which hinders downsizing of the head. Particularly, in the case of a composite type magnetic head combined with a recording head (inductive head), the number of terminals is further increased, and it becomes more difficult to reduce the size.

In order to solve this problem, in the prior art, the wiring conductor 116 on the rear end side connected to the MR element 115 formed on the substrate 114 is directly above the MR element 115 as shown in FIG. Placed across the
It has been proposed to eliminate the dedicated bias conductor for applying the bias magnetic field by configuring the R element 115 to apply the bias magnetic field.

With this arrangement, the number of terminals required for the bias conductor can be reduced, and the size of the head can be reduced.
However, since the wiring pattern 116a parallel to the ABS surface 117 is provided in the vicinity of the ABS surface 117, the off-track characteristic is deteriorated.

[0012]

Therefore, the present invention has been proposed in view of the above-mentioned conventional circumstances, and it is possible to effectively prevent the occurrence of crosstalk noise and to achieve a high track density excellent in off-track characteristics. An object of the present invention is to provide a magnetoresistive effect type magnetic head.

[0013]

The present invention has been proposed in order to achieve the above-mentioned object, and is a current-biased magnetic type in which a bias magnetic field is applied to a magnetoresistive effect element by passing a current through a conductor. In the resistance effect type magnetic head, the conductor connected to the ground portion of the magnetoresistive effect element provided between the pair of shield magnetic bodies is folded back, intersects perpendicularly with the magnetoresistive effect element, and is folded back again to form a sliding surface. When viewed from the side, it has a conductor portion that is first folded back and intersects perpendicularly with the magnetoresistive effect element, and a conductor portion that is formed so as to at least partially overlap the magnetoresistive effect element and be parallel to the conductor. It is a thing.

[0014]

In the present invention, among the conductors connected to the ground portion of the MR element provided between the shield magnetic bodies, the conductor portion that intersects with the MR element at right angles and at least partially overlaps the MR element. In the conductor part which is parallel to the conductor part, signal magnetic fluxes from adjacent tracks are crossed to generate an induced current in the same direction, but since these conductor parts are folded and connected to each other, the generated currents are mutually different. Canceled.
Therefore, generation of crosstalk noise is prevented, and off-track characteristics are improved.

[0015]

EXAMPLES Hereinafter, specific examples to which the present invention is applied will be described.
And will be described in detail with reference to the drawings. M of this embodiment
The R head, as shown in FIG. 1 and FIG.
Become Al ₂O₃-Substrate 1 made of non-magnetic material such as TiC
Wiring conductors 2 and 3 are connected to the top and the back, respectively.
And the MR element 4 is formed.
A pair of seals so that 4 is inserted from above and below
The magnetic bodies 5 and 6 are formed.

The MR element 4 is formed as a pattern having a rectangular planar shape, and is provided such that its longitudinal direction is orthogonal to the ABS surface 7 which is a sliding surface with the hard disk. One edge is AB above
It faces the S surface 7. The MR element 4 is
For example, it is made of a ferromagnetic thin film such as permalloy and is formed by vapor deposition, sputtering or the like.

In order to effectively avoid the generation of noise (Barkhausen noise) due to the movement of the domain wall, the MR element 4 has a film thickness via an intermediate layer made of a non-magnetic material such as SiO _2. It is also possible to have a laminated film structure in which thin magnetic films (MR films) are laminated.

Of the shield magnetic bodies 5 and 6 which sandwich the MR element 4 from above and below, the lower shield magnetic body 5 is made of, for example, a soft magnetic metal layer such as permalloy and has one end on the ABS surface 7. Is formed as a wide pattern having a substantially square shape in plan view. On the other hand, the upper shield magnetic body 6 is made of a soft magnetic metal layer such as permalloy as in the lower shield magnetic body 5, and has one end facing the ABS surface 7 and has a substantially square pattern in the same plane. Is formed as. In addition,
The shield magnetic body 6 in the upper layer is the MR element 4 on the ABS 7 side.
It is bent so that it is close to.

The wiring conductors 2 and 3 respectively connected to the front end and the rear end of the MR element 4 are formed on the side facing the shield magnetic body 5 in the upper layer. The wiring conductor 2 provided on the tip side (the ABS surface 7 side) of the MR element 4 is formed as a small conductor pattern having a substantially rectangular shape in plan view so that one end edge thereof faces the ABS surface 7. The wiring conductor 2 is electrically connected to the upper shield magnetic body 6. Therefore, when viewed from the MR element 4, the shield magnetic body 6 in the upper layer and the wiring conductor 2 on the tip side have substantially the same potential, and the tip portion of the MR element 4 is electrically stabilized. Further, the wiring conductor 2 is electrically connected to the shield magnetic body 6 in the upper layer, but is designed to magnetically insulate the MR element 4 and the shield magnetic body 6. The wiring conductor 2 also functions as a gap film of the reproducing magnetic gap g ₂ in the upper layer of the MR head.

On the other hand, the wiring conductor 3 provided on the rear end side is
By folding back and forming a strip-shaped conductor pattern, the conductor pattern is formed into a substantially spiral conductor pattern in plan view, and is connected to the ground portion of the MR element 4. That is, the wiring conductor 3 is M
A first conductor portion 3a partially laminated on the rear end of the MR element 4 so as to intersect the R element 4 vertically;
A second conductor portion 3b provided in parallel with the first conductor portion 3a and on the central portion of the MR element 4 in the longitudinal direction.
And a third conductor portion 3c provided behind the first conductor portion 3a and parallel to the first conductor portion 3a, and a first conductor portion connecting the first conductor portion 3a and the second conductor portion 3b. Connection part 3d
, A second connecting portion 3e connecting the second conductor portion 3b and the third conductor portion 3c, and a third connecting portion connecting the third conductor portion 3c and the ground portion (not shown). It has a spiral shape with 3f.

The first conductor portion 3a is arranged so as to extend from the rear end portion of the MR element 4 only to one side so as to intersect the MR element 4 vertically. From the opposite viewpoint, the first conductor portion 3a is drawn out from the rear end portion of the MR element 4 only to one side thereof so as to be parallel to the ABS surface 7. In addition, the first conductor portion 3a is connected to the MR element 4
At the rear end of the MR element 4, the MR element 4 is directly contacted and laminated to be electrically connected.

The second conductor portion 3b is provided in a substantially central portion of the MR element 4 so as to cross the MR element 4 and in parallel with the first conductor portion 3a. The second conductor portion 3b also functions as a bias conductor that applies a bias magnetic field to the MR element 4. Therefore, since a dedicated bias conductor for applying a bias magnetic field to the MR element 4 is not required, the number of terminals can be reduced and the head can be miniaturized. In addition, this second
The conductor portion 3b is formed such that the left and right conductor pattern lengths about the MR element 4 are substantially the same.

The third conductor portion 3c corresponds to the first conductor portion 3 described above.
It is provided behind the first conductor portion 3a so as to be substantially parallel to a. Further, the third conductor portion 3c is provided on the opposite side of the MR element 4 from the first conductor portion 3a.

The first connecting portion 3d connecting the first conductor portion 3a and the second conductor portion 3b is substantially parallel to the longitudinal direction of the MR element 4 (perpendicular to the ABS surface 7). The tips of the first conductor portion 3a and the second conductor portion 3b are provided so as to be connected to each other.

Further, the second conductor portion 3b and the third conductor portion 3
The second connecting portion 3e for connecting c is the first connecting portion 3
It is provided in parallel with d, and connects the tips of the second conductor portion 3b and the third conductor portion 3c.

The third connecting portion 3f connecting the third conductor portion 3c and the ground portion is pulled out from the rear end edge of the third conductor portion 3c to the back side in the direction perpendicular to the ABS surface 7. The tip portion is connected to the ground portion.

The wiring conductor 3 formed by folding back in this manner is in direct contact with the MR element 4 at the rear end portion of the MR element 4 for electrical connection, but in all other portions the insulating layer 8 is formed. It is configured to be laminated on the MR element 4 via the.

An underlying film 9 made of Al ₂ O _{3 that} functions as a gap film forming the reproducing magnetic gap g ₁ in the lower layer is provided between the lower shield magnetic body 5 and the MR element 4. There is. Further, between the MR element 4 and the upper shield magnetic body 6, the shield magnetic body 6 and MR
An insulating layer 10 is provided to prevent magnetic coupling with the element 4. Further, a protective film layer 11 for protecting the MR head is laminated on the upper shield magnetic body 6.

In the MR head having the above structure
For example, the signal magnetic flux from the adjacent track is sealed by the upper layer.
When the magnetic body 6 is picked up, the flow of magnetic flux is as shown in Fig. 3.
become. That is, it jumps into the upper shield magnetic body 6.
The signal flux from the tip to the lower shield magnetic body 5
Although it drops strongly, it is pulled up to the vicinity of the wiring conductor 3. This
Therefore, it is provided in parallel with the ABS surface 7 and
By the magnetic flux interlinking with the closest second conductor portion 3b,
The induced current i that causes crosstalk noise.₁Flow
Be done. Similarly, in the first conductor portion 3a and the third conductor portion 3c
Also induced current i₂, I ₃Flows. These first conductor parts 3
a, induction flowing through the second conductor portion 3b and the third conductor portion 3c
Current i₁, I₂, I₃Both have the same orientation.

At this time, since the wiring conductor 3 on the rear end side is formed by connecting the first conductor portion 3a, the second conductor portion 3b, and the third conductor portion 3c by being folded back, Current i
₁ , i ₂ , i ₃ cancel each other. That is, the induced currents i ₂ and i ₃ generated in the first conductor portion 3a and the third conductor portion 3c flow counterclockwise, while the induced current i ₁ generated in the second conductor portion 3b rotates clockwise. As they flow, they cancel each other out. Therefore, crosstalk noise is not generated, and the off-track characteristic can be improved, which can increase the track density.
The effect is clear from FIG. The middle line a in FIG.
The waveform indicated by is the off-track characteristic in the conventional MR head shown in FIG. 11, and the waveform indicated by the line b is M in this embodiment.
The off-track characteristic in R head is shown.

The specific embodiment to which the present invention is applied has been described above, but the present embodiment is not limited to the above-described embodiment and various modifications can be made. For example, as shown in FIGS. 4 and 5, the upper and lower shield magnetic bodies 5 and 6 are
By magnetically joining in the vicinity of the S surface, the effect of attracting the magnetic flux may be further strengthened and the cancel effect may be further enhanced. That is, the magnetic coupling portion 12 is pulled out from the vicinity of the rear end edge of the upper shield magnetic body 6 (behind the third conductor portion 3c) to the lower shield magnetic body 5 side.
The magnetic coupling portion 12 is magnetically connected to the shield magnetic body 5 in the lower layer.

With such a structure, the signal magnetic flux from the adjacent track has a lower magnetic resistance when it passes through the magnetic coupling portion 12, and therefore most of it is pulled up to this point. As a result, the difference in the interlinkage magnetic flux due to the distance difference between the second conductor portion 3b and the first and third conductor portions 3a and 3c from the ABS surface 7 disappears, and it can be canceled more effectively. The off-track characteristic of the head in this configuration is shown in FIG.
As shown by the middle line c, it is still good. In addition,
Since the upper and lower shield magnetic bodies 5 and 6 are magnetically connected, in order to avoid contact between the wiring conductor 3 and the magnetic coupling portion 12, the conductor length of the third conductor portion 3c is the same as that in the previous embodiment. It's longer than the one.

In addition, as shown in FIG. 6, even if the third conductor portion 3c is formed so as not to be parallel to the ABS surface 7 but to be slightly inclined, the conductor portions 3a, 3b and 3c will be The induced currents i ₁ , i ₂ and i ₃ that are generated can cancel each other out, and the off-track characteristics can be improved.

It should be noted that in the above-mentioned embodiment, the MR exclusively for reproduction is used.
This is an example in which only the head is formed on the substrate.
Similar effects can be obtained even with a composite type thin film magnetic head structure in which an inductive head dedicated to recording is laminated on the head.

[0035]

As is apparent from the above description, in the present invention, the conductor patterns are such that the induced currents generated by the signal magnetic fluxes from the adjacent tracks crossing the wiring conductors can be canceled from each other. In addition, since the wiring conductor is formed by folding back, it is possible to prevent the occurrence of crosstalk noise, and it is possible to obtain excellent off-track characteristics. Therefore, the signal information written in the hard disk can be surely read out, and the track density can be increased.

[Brief description of drawings]

FIG. 1 is an enlarged plan view of an essential part of an MR head to which the present invention is applied.

FIG. 2 is an enlarged cross-sectional view of a main part of the MR head shown in FIG.

3 is a diagram showing a flow of signal magnetic flux from an adjacent track in the MR head shown in FIG.

FIG. 4 MR in which upper and lower shield magnetic bodies are magnetically coupled
It is a principal part enlarged plan view of a head.

5 is a diagram showing a flow of signal magnetic flux from an adjacent track in the MR head shown in FIG.

FIG. 6 is an enlarged plan view of an essential part of the MR head, showing an example in which a part of the wiring conductor is inclined with respect to the ABS surface.

FIG. 7 is a characteristic diagram showing off-track characteristics.

FIG. 8 is an enlarged plan view of a main part of a conventional horizontal MR head.

FIG. 9 is an enlarged plan view of a main part of a conventional vertical MR head.

10 is an enlarged cross-sectional view of essential parts of the vertical MR head shown in FIG.

FIG. 11 is an enlarged plan view of an essential part of an MR head showing an example in which a wiring conductor has a function of applying a bias magnetic field to an MR element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Lead-side wiring conductor 3 ... Rear-end side wiring conductor 3a ... First conductor portion 3b ... Second conductor portion 3c ... Third conductor Part 3d ... 1st connection part 3e ... 2nd connection part 3f ... 3rd connection part 4 ... MR element 5 ... Lower layer shield magnetic body 6 ... Upper layer shield Magnetic material 7 ... ABS surface

Claims (1)

[Claims] 1. A current-bias type magnetoresistive effect magnetic head for applying a bias magnetic field to a magnetoresistive effect element by passing a current through a conductor, wherein a ground portion of the magnetoresistive effect element provided between a pair of shield magnetic bodies. The conductor connected to and intersects perpendicularly with the magnetoresistive effect element, and by folding again, the conductor part that first folds when viewed from the sliding surface side and intersects perpendicularly with the magnetoresistive effect element. A magnetoresistive effect magnetic head having a conductor portion formed so as to at least partially overlap the magnetoresistive effect element and be parallel to the conductor.