JPH06267027A - Magnetoresistance effect type thin film magnetic head - Google Patents

Abstract

(57) [Abstract] [Purpose] The crosstalk component directly entering the MR element from between the upper and lower shield magnetic bodies and the crosstalk component due to the electromagnetic induction of the bias conductor and the electrode are reduced to reduce the S of the reproduced signal.
/ N and reliability of servo signals and the like. A lower shield magnetic body 2 is formed on a non-magnetic substrate 11 with an insulating layer 12 interposed, and an insulating layer 13 forming a first reproduction gap is laminated on the lower shield magnetic body 2. The MR element 1 is formed on the layer 13, the insulating layer 14 forming the second reproducing gap is further formed on the MR element 1, and the upper shield magnetic body 3 is laminated on the insulating layer 14. In the MR thin film head, the distance g1 between the upper and lower shield magnetic bodies 3 and 2 in the portion without the MR element 1 is set to be 1/2 or less of the distance g2 in the portion with the MR element 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a magnetoresistive effect thin film whose resistivity changes according to a recording magnetic field from a magnetic recording medium, and detects a change in resistance of the magnetoresistive effect thin film as a reproduction output voltage. Type magnetic head.

[0002]

2. Description of the Related Art In recent years, as hard disk devices have become smaller and have larger capacities, particularly in applications where portable computers such as notebook computers are considered, for example, a 2.5-inch hard disk. The demand for equipment is increasing.

In such a small hard disk, the medium speed becomes slow depending on the disk diameter. Therefore, in the conventional induction type magnetic head in which the reproducing output depends on the medium speed, the reproducing output is lowered and the increase in capacity is hindered. Has become.

However, a magnetoresistive effect type magnetic head which detects a change in resistance of a magnetoresistive effect element (hereinafter, simply referred to as an MR element) whose resistivity changes according to a magnetic field as a reproduction output voltage has a reproduction output at a medium speed. Since it has the feature that it can obtain a high reproduction output even at a low medium speed,
It is attracting attention as a magnetic head that realizes a large capacity in a small hard disk.

Conventionally, in order to realize the above-mentioned MR head as a magnetic head of a hard disk device, a thin film magnetoresistive effect element (hereinafter, simply referred to as an MR element) is provided on a slider material and a lower part is used as a magnetic path during reproduction. A magnetoresistive effect type thin film magnetic head (hereinafter referred to as an MR thin film head) having a structure sandwiched between a shield core and an upper shield core is formed.

Specifically, taking a vertical MR thin film head as an example, as shown in FIGS. 5 and 6, a lower shield magnetic body 1 is formed on a non-magnetic substrate 101 with an insulating layer 102 interposed therebetween.
03, a soft magnetic film and an insulating layer 104 are sequentially laminated, and the MR element 105 is arranged on the insulating layer 104 so that its longitudinal direction is perpendicular to the surface (head surface a) facing the magnetic recording medium. Then, one end surface of the MR film 105 is formed so as to be exposed to the head surface a, and further, a front end electrode 106a and a rear end electrode 106b for supplying a sense current to both ends of the MR film 105 are formed.

After that, the insulating layer 107 is formed on the entire surface including the MR element 105, the front end electrode 106a, and the rear end electrode 106b.
Is formed, a bias conductor 108 is formed so as to traverse the MR element 105 in the lower layer in the longitudinal direction, and then an insulating layer 109 and a soft magnetic film to be the upper shield magnetic body 110 are sequentially laminated on the entire surface. The MR thin film head in FIG. In the illustrated example, the rear electrode 1
06b and the bias conductor 109 are connected in series.

On the other hand, in the horizontal MR thin film head,
As shown in FIGS. 7 and 8, the MR element 105 is arranged such that its longitudinal direction is parallel to the head surface a and one end of its longitudinal direction is exposed on the head surface a. ing. Then, the bias conductor 108 is formed on the MR element 105 via the insulating layer 107, and the first electrodes 111a and 111b are formed at both ends of the MR element 105 in the longitudinal direction.
The sense current is configured to flow along the longitudinal direction of (i.e., along the head surface a).

Both the vertical and horizontal MR thin film heads have a structure in which the MR film 105 is sandwiched between the upper shield magnetic body 110 and the lower shield magnetic body 103. It is possible to improve the recording density dependency of the reproduction output.

[0010]

By the way, in a conventional vertical MR thin film head, for example, as shown in FIG.
The upper and lower shield magnetic bodies 110 and 103 that magnetically shield the MR element 105 are formed to face each other substantially in parallel, and the distance between the upper and lower shield magnetic bodies 110 and 103 at the position where the MR element 105 is located. And MR
The distance between the upper and lower shield magnetic bodies 110 and 103 at a position where the element 105 is not located is almost the same.

In this case, the upper and lower shield magnetic bodies 1
The magnetic flux having a somewhat low frequency component input as the reproduction gap at the distance between 10 and 103 is generated by the MR element 10.
5 and is output as a crosstalk component other than the intended signal component, or is connected to both ends of the sensing portion of the MR element 105.
The crosstalk component generated by electromagnetic induction in 6b is
There is a problem in that the signal component that is originally output from the MR element 105 is superimposed and output.

These crosstalk components have a problem of deteriorating the S / N of the original signal component. Especially, in the case of a hard disk device, a reproducing head (MR thin film head).
Therefore, when the servo signal or the tracking signal is taken out from the surface of the recording medium, the quality of the servo signal or the like is deteriorated due to the superposition of the crosstalk component.

FIG. 10 shows the off-track characteristics of the conventional MR thin film head. From this off-track characteristic, when the output level of the portion where MR element 105 is located (indicated by section BC) in the width direction of upper and lower shield magnetic bodies 110 and 103 is 0 dB, MR element 105
Where is not located (indicated by section AB and section C-D)
It can be seen that a crosstalk component having an output level of −20 and several dB is contained in.

The same applies to a lateral MR thin film head,
The first electrode 111a, the MR element 105 and the second electrode 1
Crosstalk components from the upper and lower shield magnetic bodies 110 and 103 enter the MR element 105 by the electromagnetic induction generated in the loop formed by 11b, and a crosstalk component having the same output level as in FIG. 10 is output. .

As described above, in the conventional MR thin film head, the MR is removed from between the upper and lower shield magnetic bodies 110 and 103.
The crosstalk component directly entering the element 105, the bias conductor 108 and the electrode (the front end electrode 106a in the vertical type)
Also, the crosstalk component due to the electromagnetic induction of the rear end electrode 106b, and in the horizontal type, the first and second electrodes 111a and 111b) is output by being superimposed on the original signal component, and the S / N ratio of the reproduction signal is increased. There is a problem that the reliability of the servo signal and the like also deteriorates with the deterioration.

The present invention has been made in view of the above problems, and its object is to provide a crosstalk component directly entering the MR element from between the upper and lower shield magnetic bodies that are superposed on the original signal component, and a bias. To provide a magnetoresistive thin-film magnetic head capable of reducing crosstalk components due to electromagnetic induction of conductors and electrodes, improving S / N of reproduced signals, and reliability of servo signals and the like. is there.

[0017]

According to the present invention, a magnetoresistive effect element 1 having a magnetoresistive effect is exposed on a recording medium sliding surface a, and a nonmagnetic layer 13 sandwiching the magnetoresistive effect element 1 in the film thickness direction. In the magnetoresistive thin-film magnetic head having a structure magnetically shielded by the upper and lower shield magnetic bodies 3 and 2 each of which is composed of a soft magnetic layer via
Compared with the distance g2 between the upper shield magnetic body 3 and the lower shield magnetic body 2 in the formation position of the magnetoresistive effect element 1 in the portion exposed on the sliding surface of the recording medium, the magnetoresistive effect element 1 in the non-formed position is The distance g1 between the upper shield magnetic body 3 and the lower shield magnetic body 2 is set to 1/2 or less.

[0018]

In the magnetoresistive thin film magnetic head according to the present invention, there is no magnetoresistive effect element (hereinafter simply referred to as MR element) 1 in the exposed portions of the upper and lower shield magnetic bodies 3 and 2 on the head surface a. However, the distance g1 between the upper and lower shield magnetic bodies 3 and 2 is smaller than the distance g2 where the MR element 1 is present, or the upper and lower shield magnetic bodies 3 and 2 where there is no MR element 1 is magnetically short-circuited. become.

When the distance g1 between the upper and lower shield magnetic bodies 3 and 2 in the absence of the MR element 1 becomes small, the magnetic resistance at that portion becomes small and the input of magnetic flux of low frequency component decreases. Further, as compared with the case where the MR element 1 is present (the magnetic resistance is large), more magnetic flux of the crosstalk component other than the original signal component that has entered from the head surface a is made to flow (drop).

As a result, the crosstalk component due to electromagnetic induction generated at the bias conductor and the electrode for flowing the sense current and the crosstalk component directly entering the MR element 1 from the upper and lower shield magnetic bodies 3 and 2 are significantly reduced. become.

[0021]

EXAMPLE An example of a magnetoresistive thin-film magnetic head according to the present invention (hereinafter simply referred to as an MR thin-film head according to the example) will be described with reference to FIGS.

The MR thin film head according to this embodiment is shown in FIG.
As shown in FIG. 3, a magnetoresistive effect element (hereinafter, simply referred to as an MR element) 1 has a structure in which a lower shield magnetic body 2 and an upper shield magnetic body 3 which serve as a magnetic path during reproduction are sandwiched.

Specifically, the lower shield magnetic body 2 made of a magnetic film such as Ni--Fe is formed on the non-magnetic substrate 11 via the insulating layer 12, and the first reproduction is performed on the lower shield magnetic body 2. An insulating layer 13 such as alumina that forms a gap is laminated. Then, on the insulating layer 13, for example, F
The MR element 1 made of the e-Ni film is formed, and
The MR thin film head according to this embodiment is formed by forming the insulating layer 14 forming the second reproducing gap on the element 1 and stacking the upper shield magnetic body 3 made of a magnetic film such as Fe-Ni on the insulating layer 14. Is configured.

In the vertical MR thin film head, as shown in FIG. 3, the MR element 1 is arranged such that its longitudinal direction is perpendicular to the surface facing the magnetic recording medium, that is, the recording medium sliding surface a. And one end surface thereof is exposed on the recording medium sliding surface a. Electrodes (a front end electrode 21a and a rear end electrode 21b) made of a soft magnetic film are respectively formed at an end (hereinafter, referred to as a front end) of the MR element 1 on a recording medium sliding surface side and a position separated from the front end by a predetermined distance. Has been formed.

The front end electrode 21a and the rear end electrode 21b
Are formed for the purpose of flowing a sense current along the longitudinal direction of the MR element 1 (that is, in the direction orthogonal to the recording medium sliding surface a). In the present embodiment, since the front end electrode 21a is formed in a separately separated form, after the insulating layer 14 is formed, the surface is planarized to expose the upper surface of the front end electrode 21a,
After that, the upper shield magnetic body 3 is formed,
The front end electrode 21a and the upper shield magnetic body 3 are electrically connected. Therefore, in this case, the front end electrode 2
A second reproduction gap is formed at 1a.

In this vertical MR thin film head, the region between the rear end of the front end electrode 21a and the front end of the rear end electrode 21b in the MR element 1 exhibits a magnetoresistive effect, and this region is This constitutes the sensing unit 1a of the MR element 1. In addition, on the sensing portion 1a of the MR film 1, the MR
Bias conductor 22 for applying a bias magnetic field to the membrane 1
Are formed so as to cross over the MR film 1.

On the other hand, in the horizontal type MR thin film head,
As shown in FIG. 4, the MR element 1 is arranged such that its longitudinal direction is parallel to the recording medium sliding surface a, and one end of the longitudinal direction is exposed on the recording medium sliding surface a. Is formed in. Then, the insulating layer 1 is formed on the MR element 1.
Bias conductors (not shown) are formed via the electrodes 4, and electrodes 23a and 23b are formed on both ends of the MR element 1 in the longitudinal direction, respectively. A sense current is configured to flow (along the moving surface a).

In the MR thin film head according to the present embodiment, as shown in FIGS. 1, 3 and 4, the MR element 1, the bias conductor 22 and the electrode (in the vertical type, the front end electrode 21a and the rear end electrode 21a). 21b, in the horizontal type, except for the first and second electrodes 23a and 23b), a recessed region 24 that intentionally reduces the distance between the upper and lower shield magnetic bodies 3 and 2 from the recording medium sliding surface a to the vicinity of its depth. Are formed and configured.

As a method of forming the recessed region 24, taking a vertical MR thin film head as an example, for example, before forming the MR element 1, the insulating layer 13 (for example, on the lower shield magnetic body 2 which is the lower layer in advance) is formed. The recessed region 24 can be formed by partially removing Al ₂ O ₃ ) by a lift-off method or an etching method. As a result, the distance g1 (see FIG. 1) between the upper and lower shield magnetic bodies 3 and 2 in the portion where the MR element 1 is absent is reduced by the thickness of the insulating layer 13, and specifically, in the portion where the MR element 1 is present. It is about 1/2 of the distance g2.

As another method for reducing the distance g1 between the upper and lower shield magnetic bodies 3 and 2, for example, the MR element 1 is used.
A part of the insulating layer 14 formed above, for example, SiO ₂ or Si ₃ N ₄ (in the vertical MR thin film head in FIG. 3, when the length of the front end electrode 21a in the longitudinal direction is increased, The recessed region 24 may be formed by removing (including a part thereof) by an etching method.

Here, the off-track characteristics when the distance g1 between the upper and lower shield magnetic bodies 3 and 2 in the portion without the MR element 1 is about 1/2 of the distance g2 in the portion with the MR element 1 is As shown in FIG. 2, when the output level of the portion where MR element 1 is located (shown in section BC) is 0 dB in the width direction of the upper and lower shield magnetic bodies 3 and 2, the MR element 1 is It can be seen that the output level of the crosstalk component i in the non-positioned portion (shown by the section AB and the section CD) is lowered by 3 dB or more as compared with the conventional case (shown by the chain double-dashed line) j.

By combining the above two methods, a deeper recessed region 24 is formed, and the upper and lower shield magnetic bodies 3 and 2 in that region are almost magnetically coupled. Actually, in order to secure the adhesion strength of the upper shield magnetic body 3, a non-magnetic metal layer such as Ti (titanium) or Cr (chrome) having a thickness of about 0.03 μm is provided between the upper and lower shield magnetic bodies 3 and 2. Although intervening, at such a small interval, it becomes a magnetically short-circuited state.

The off-track characteristic in this case is, as shown in FIG. 2, the output level at the position where the MR element 1 is located (indicated by section B-C) in the width direction of the upper and lower shield magnetic bodies 3 and 2. Is 0 dB, the output level of the crosstalk component k (indicated by a broken line) at a location where the MR element 1 is not located (indicated by sections AB and C-D) is -30 dB, which is the case of the conventional case. Will be significantly lower than.

As described above, in the MR thin film head according to the above-described embodiment, the upper and lower shield magnetic bodies 3 where the MR element 1 is absent in the exposed portions of the upper and lower shield magnetic bodies 3 and 2 on the recording medium sliding surface a. And the distance g1 between 2 and
It is smaller than the distance g2 where the MR element 1 is,
Alternatively, since the upper and lower shield magnetic bodies 3 and 2 without the MR element 1 are magnetically short-circuited, the magnetic resistance between the upper and lower shield magnetic bodies 3 and 2 without the MR element 1 becomes small. , The input of the magnetic flux of the low frequency component will decrease. Further, as compared with the case where the MR element 1 is present (the magnetic resistance is large), more magnetic flux of the crosstalk component other than the original signal component that has entered from the sliding surface a of the recording medium flows (drops).

As a result, the electromagnetic induction generated in the bias conductor 22 and the electrodes for flowing the sense current (the front end electrode 21a and the rear end electrode 21b in the vertical type, the first and second electrodes 23a and 23b in the horizontal type) From the crosstalk component and the upper and lower shield magnetic bodies 3 and 2
Therefore, the crosstalk component that directly enters in is significantly reduced.

As described above, in the MR thin film head according to this embodiment, the crosstalk component directly entering the MR element 1 from between the upper and lower shield magnetic bodies 3 and 2 superimposed on the original signal component, and the electromagnetic wave of the conductor. Since the crosstalk component due to induction can be reduced, the S of the reproduction signal is reduced.
It is possible to improve / N and reliability of the servo signal and the like, and it is possible to obtain a reproduction signal with a small error rate and a servo signal with a small error.

[0037]

As described above, according to the magnetoresistive effect type thin film magnetic head of the present invention, the magnetoresistive effect element having the magnetoresistive effect is exposed on the sliding surface of the recording medium, and the magnetoresistive effect element is provided. In a magnetoresistive thin-film magnetic head configured to be magnetically shielded by upper and lower shield magnetic bodies composed of soft magnetic layers through nonmagnetic layers sandwiched in the film thickness direction, exposed on the sliding surface of the recording medium. Compared with the distance between the upper shield magnetic body and the lower shield magnetic body at the formation position of the magnetoresistive effect element in the above-mentioned portion, the distance between the upper shield magnetic body and the lower shield magnetic body at the non-formation position of the magnetoresistive effect element Since the distance was reduced to less than 1/2, the MR was removed from between the upper and lower shield magnetic bodies that were superimposed on the original signal component.
It is possible to reduce the crosstalk component directly entering the element and the crosstalk component due to the electromagnetic induction of the bias conductor and the electrode, and it is possible to improve the S / N of the reproduction signal and the reliability of the servo signal and the like.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing an embodiment of a magnetoresistive thin-film magnetic head according to the present invention (hereinafter, simply referred to as an MR thin-film head according to the embodiment) as viewed from a recording medium sliding surface.

FIG. 2 is a characteristic diagram showing the off-track characteristics in the width direction of the upper and lower shield magnetic bodies of the MR thin film head according to the present embodiment.

FIG. 3 is a plan view showing the configuration of a vertical MR thin film head according to the present embodiment with the upper shield magnetic body removed.

FIG. 4 is a plan view showing the configuration of a lateral MR thin film head according to the present embodiment with the upper shield magnetic body removed.

FIG. 5 is a cross-sectional view showing a configuration of a vertical MR thin film head according to a conventional example.

FIG. 6 is a plan view showing a configuration of a vertical MR thin film head according to a conventional example with an upper shield magnetic body removed.

FIG. 7 is a sectional view showing a configuration of a lateral MR thin film head according to a conventional example.

FIG. 8 is a plan view showing a configuration of a lateral MR thin film head according to a conventional example with an upper shield magnetic body removed.

FIG. 9 is a perspective view of a main part showing an MR thin film head according to a conventional example as viewed from a sliding surface of a recording medium.

FIG. 10 is a characteristic diagram showing off-track characteristics in the width direction of the upper and lower shield magnetic bodies of the MR thin film head according to the conventional example.

[Explanation of symbols]

1 MR element 2 Lower shield magnetic body 3 Upper shield magnetic body 11 Substrate 12, 13, 14 Insulating layers 21a and 21b Front and rear end electrodes 22 Bias conductors 23a and 23b First and second electrodes 24 Recessed area g1 MR element Distance between upper and lower shield magnetic bodies where there is no g2 Distance between upper and lower shield magnetic bodies where there is an MR element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuji Shibata 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (1)

[Claims] 1. A magnetoresistive effect element having a magnetoresistive effect is exposed on a sliding surface of a recording medium, and an upper portion composed of a soft magnetic material layer and a non-magnetic layer sandwiching the magnetoresistive effect element in the film thickness direction, respectively. In a magnetoresistive thin-film magnetic head magnetically shielded by a lower shield magnetic body, an upper shield magnetic body and a lower shield at a position where the magnetoresistive element is formed in a portion exposed on the sliding surface of the recording medium. Compared with the distance between the magnetic bodies, the distance between the upper shield magnetic body and the lower shield magnetic body at the position where the magnetoresistive effect element is not formed is ½ or less, and the magnetoresistive effect thin film magnetic. head.