JPH09106511A - Magneto-resistance effect magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect minute magnetic field in high sensitivity and to improve productivity also without forming a bias conductor. SOLUTION: A magneto-resistance effect element consisting of two layers of MR films 7, 8 is arranged between a pair of shield magnetic bodies arranged at a prescribed interval facing to a magnetic recording medium opposite surface so as to become the direction nearly perpendicular to the magnetic recording medium opposite surface, and the directions of sense currents of respective MR films 7, 8 shown by the arrows S7 , S8 are made the directions having nearly equal angles shown by θ7 , θ8 for the orthogonal direction shown by the arrows V7 , V8 and sloping to the opposite directions each other. Further, it is preferable that the θ7 , θ8 are made nearly 45 deg., and the directions of the sense currents each other are nearly orthogonally intersected with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect including a pair of shield magnetic bodies arranged at a predetermined interval facing a magnetic recording medium facing surface, and having a two-layer magnetoresistive film between the shield magnetic bodies. The present invention relates to a so-called two-layer vertical magnetoresistive effect magnetic head in which elements are arranged in a direction substantially orthogonal to a surface facing a magnetic recording medium. More specifically, it relates to a magnetoresistive effect magnetic head capable of detecting a minute magnetic field with high sensitivity without forming a bias conductor by controlling the direction of the sense current flowing in the magnetoresistive effect element. is there.

[0002]

2. Description of the Related Art For example, a so-called two-layer vertical magnetoresistive effect magnetic head (hereinafter referred to as a two-layer vertical MR head) is used as a reproducing magnetic head in a magnetic recording / reproducing apparatus such as a hard disk drive. As shown schematically in FIG. 7, a pair of shield magnetic bodies arranged to face each other with magnetic gaps G ₁ , G ₂ and G ₃ which are gaps facing the magnetic recording medium facing surface 103. A magnetoresistive effect element 111 (hereinafter referred to as an MR element 111) is sandwiched between 101 and 102 with nonmagnetic insulating layers 104 and 106 interposed therebetween. Then, the MR element 111
Are two layers of magnetoresistive effect films 107 and 108 (hereinafter referred to as MR films 107 and 1) that are stacked with a non-magnetic insulating layer 105 interposed therebetween.
08. ) Consists of.

That is, in the above-mentioned two-layer vertical MR head, a pair of shield magnetic bodies 101 and 102 shield an extra external magnetic field so that only the desired external magnetic field constitutes the MR film 107. 108, and the MR films 107, 1 are generated by the external magnetic field.
Information is reproduced by utilizing the change in the resistance of 08.

Further, in the MR element 111,
Electrodes (not shown) are laminated and formed on the front and rear ends of the MR films 107 and 108 which are the magnetically sensitive portions.

Therefore, information is reproduced from the electrodes by MR.
A sense current is passed through the films 107 and 108, and the M
The R films 107 and 108 are magnetized in a predetermined direction, and a change in the resistance value of the MR films 107 and 108 caused by a change in the magnetization direction due to an external magnetic field is detected as a voltage change.

In the two-layer vertical MR head, the magnetoresistive effect characteristic of the MR element 111 has excellent linearity so that the MR element 111 operates in a characteristic region showing high sensitivity. A bias conductor 109 for passing a bias current is provided across the MR films 107 and 108 of the MR element 111 via the insulating layer 104.

Further, in the MR head as described above, the bias conductor 109 is connected to, for example, the shield magnetic body 10 which is one of the pair of shield magnetic bodies 101 and 102.
The groove portion 110 provided in the MR element facing surface 101a of No. 1 is embedded via the non-magnetic material 104 to ensure the insulation between the bias conductor 109 and the shield magnetic body 101.

FIG. 8 shows the relationship between the external magnetic field and the resistances of the MR films 107 and 108 when a bias current does not flow in the two-layer vertical MR head having the above structure. As can be seen from FIG. 8, when the external magnetic field is zero, the magnetization direction of the MR film is naturally not affected by the external magnetic field, so that the resistance of the MR film has a minimum value. On the other hand, from the result of FIG. 8, the external magnetic field is about ± 5 (Oe) to ± 50 (Oe)
In the range of e), the resistance value of the MR film changes with excellent linearity, and since the change is abrupt, it can be seen that the sensitivity of the MR film is good.

Therefore, as described above, the bias conductor 109 is used.
Is arranged so as to cross the MR films 107 and 108.
As shown schematically in FIG. 3, a sense current flows in the MR films 107 and ₁₀₈ from the rear end side to the front end side, as indicated by arrows S ₁₀₇ and S ₁₀₈ in the figure, while the bias conductor 109 does not. As indicated by an arrow B in the figure, for example, a bias current flows from the front side to the back side in the figure in a direction orthogonal to the arrows S ₁₀₇ and S _{108 in the} figure.

That is, when a bias current is applied to the bias conductor 109, a bias magnetic field is generated around the bias conductor 109 in the direction indicated by arrow h ₂ in the figure. This bias magnetic field is a magnetic field in the opposite direction to the leakage magnetic field from the magnetic recording medium that enters from the tip side of the MR films 107 and 108 as indicated by an arrow h ₁ in the figure.

Therefore, in this state, the MR films 107 and 108 are
The actual strength of the stray magnetic field sensed by is the original strength minus the bias magnetic field, and the relationship between the external magnetic field and the resistance of the MR film in this state is as shown in FIG. Compared with this, it is shifted in the positive direction as a whole. As a result, in the vicinity of zero external magnetic field (Oe), the magnetoresistive effect characteristics of the MR films 107 and 108 have excellent linearity, and the MR films 107 and 108 are operated in a characteristic region showing high sensitivity. Thus, the MR element 111 can detect a minute magnetic field with high sensitivity.

[0012]

When the bias conductor is provided in the two-layer vertical MR head as described above, not only the wiring of the bias conductor but also the insulation between the bias conductor and the magnetic shield is ensured. It is necessary to form a groove in the magnetic shield.

However, these steps are very complicated and are a factor that hinders the improvement of the productivity of the two-layer vertical MR head.

Therefore, the present invention has been proposed in view of the conventional circumstances, and it is not necessary to form a bias conductor, a minute magnetic field can be detected with high sensitivity, and the productivity is good. An object is to provide a layer vertical MR head.

[0015]

In order to solve the above-mentioned problems, the present invention provides a pair of shield magnetic bodies arranged at a predetermined interval facing the magnetic recording medium facing surface, and between the shield magnetic bodies. The magnetoresistive effect element of the magnetoresistive effect type magnetic head in which the magnetoresistive effect element is arranged in a direction substantially orthogonal to the surface facing the magnetic recording medium is composed of two layers of magnetoresistive effect films laminated via an insulating layer. However, the directions of the sense currents of the respective magnetoresistive films are tilted in the opposite directions with respect to the orthogonal direction by substantially equal angles.

In the magnetoresistive effect type magnetic head of the present invention, it is preferable that the sense current directions of the magnetoresistive effect films are tilted by approximately 45 ° with respect to the orthogonal direction and are substantially orthogonal to each other.

The anisotropic magnetoresistive effect seen in the magnetoresistive film is the difference between the angle formed by the sense current direction with respect to one direction of the magnetoresistive film and the angle formed by the magnetization spin with respect to the one direction. It is proportional to the square of the cosine.

In a two-layer vertical magnetoresistive effect type magnetic head, as schematically shown in FIG.
As indicated by arrows S ₁₀₇ and S ₁₀₈ in the figure, a sense current is made to flow from the rear end side to the front end side, in other words, in the longitudinal direction.
_The magnetization spins appearing in the width direction indicated by ₁₀₇ and J ₁₀₈ are orthogonal to each other.

That is, when the bias magnetic field is not present and the external magnetic field is zero, the sense current and the magnetization spin are orthogonal to each other, and the angle formed by the sense current direction with respect to one direction of the magnetoresistive film. And the angle formed by the magnetization spin with respect to the above-mentioned one direction, in other words, the angle formed by the magnetization spin and the direction of the sense current is 90 °. Therefore, the anisotropic magnetoresistive effect takes the minimum value, and the resistance value takes the minimum value as shown in FIG. Therefore, when there is no bias magnetic field and the external magnetic field is near zero, the influence of the anisotropic magnetoresistive effect is small, and accordingly, the change in the resistance value is small as shown in FIG. .

In the magnetoresistive effect magnetic head of the present invention, as described above, the magnetic recording is performed by being sandwiched between a pair of shield magnetic bodies arranged with a predetermined interval facing the magnetic recording medium facing surface. The magnetoresistive effect element arranged in a direction substantially orthogonal to the medium facing surface is composed of two layers of magnetoresistive effect films laminated with an insulating layer in between, and the direction of the sense current of each magnetoresistive effect film is set to The directions are inclined in the opposite directions with respect to the orthogonal direction by substantially equal angles.

The magnetization spins of the magnetoresistive film of the magnetoresistive magnetic head having such a structure usually appear in the width direction of the magnetoresistive film as described above, and the magnetization spins are orthogonal to the orthogonal direction. Will be done. That is, if the angle formed by the orthogonal direction and the sense current direction is θ, the angle formed by the magnetization spin and the sense current is 90 ° −θ. Therefore, the sense currents of the two-layered magnetoresistive films are inclined in directions opposite to each other by substantially equal angles with respect to the magnetization spins, and the sense current direction and the magnetization spins are not orthogonal to each other. .

Therefore, even when there is no bias magnetic field and the external magnetic field is zero, the anisotropic magnetoresistive effect does not reach the minimum value, the resistance value does not reach the minimum value, and the external magnetic field is very small near zero. Even in a magnetic field, the change in the resistance value of the magnetoresistive film becomes large.

In such a two-layer vertical magnetoresistive effect type magnetic head, it is energetically stable that the magnetization spins of the two-layer magnetoresistive effect films of the magnetoresistive effect element are in antiparallel state. It is said that.

Therefore, at this time, in the magnetoresistive effect type magnetic head of the present invention, the direction of the sense current of each magnetoresistive effect film is inclined by about 45 ° with respect to the orthogonal direction,
By making them substantially orthogonal to each other, the same applies to the magnetization spin, and the magnetic behavior of the magnetoresistive film is most stable.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings.

The magnetoresistive effect magnetic head of this example is a so-called two-layer vertical magnetoresistive effect magnetic head (hereinafter referred to as a two-layer vertical MR head), and as shown schematically in FIG. , A non-magnetic insulating layer 4 between a pair of shield magnetic bodies 1 and 2 arranged facing each other with magnetic gaps g ₁ , g ₂ and g ₃ facing the magnetic recording medium facing surface 3. , 6
The magnetoresistive effect element 12 (hereinafter referred to as the MR element 12) is sandwiched between the two. The MR element 12 is composed of two layers of magnetoresistive effect films 7 and 8 (hereinafter, referred to as MR films 7 and 8) laminated with a nonmagnetic insulating layer 5 interposed therebetween.

The pair of shield magnetic bodies 1 and 2 are arranged so as to shield an extra external magnetic field so that only the desired external magnetic field enters the MR films 7 and 8 constituting the MR element 12. is there.

Further, in the MR element 12, electrodes are laminated on the front and rear ends of the MR films 7 and 8 which are magnetically sensitive portions, as shown schematically in FIG. In the figure, only the MR film 8 is shown.), Electrodes 9 and 10 are connected to the side surfaces of the front and rear ends of the MR film 8 so that the sense current of the MR film 8 is as indicated by an arrow S ₈ in the figure. It is designed to flow diagonally. Note that such a connection method is generally called a side contact.

In the two-layer vertical MR head of this example, the sense currents of the MR films 7 and 8 are as shown by arrows S ₇ and S ₈ in the figure, as schematically shown in FIG. ,
The angles of the MR films 7 and ₈ with respect to the direction orthogonal to the magnetic recording medium facing surface 3 (corresponding to the longitudinal direction) indicated by arrows V ₇ and V ₈ in the drawing, which are indicated by θ _{7 in the} drawing and θ ₈ in the drawing, respectively. And flow in such a manner that they are inclined in opposite directions. Then, the angles indicated by θ ₇ and θ ₈ in the figure are
The angles are 45 °, which are the same.

In the two-layer vertical MR head of this example, due to the constitution, the magnetization spins of the two-layer MR films 7 and ₈ are as shown by arrows J ₇ and J ₈ in FIG. This magnetized spin appears in the width direction of ₈ and is orthogonal to the direction orthogonal to the magnetic recording medium facing surface 3 shown by arrows V ₇ and V ₈ in the figure. That is, the angle theta ₇ the direction of the orthogonal direction and the sense current is formed, relative theta _8, the angle of the magnetization spin and the sense current is 90 ° - [theta] _7, 90 ° - [theta] _8. From this, the directions of the sense currents of the two layers of the MR films 7 and 8 are inclined to the opposite directions with an angle of 45 ° with respect to the magnetization spin in the width direction. The directions are orthogonal to each other.

Further, in the two-layer vertical MR head of this example, in order to secure energy stability, as shown in FIG. 3, the magnetization spin of the MR film 7 indicated by the arrow J ₇ in the drawing, The magnetization spins of the MR film 8 indicated by an arrow J ₈ in the drawing are antiparallel.

In the two-layer vertical MR head of this example, in order to reproduce information, for example, a sense current is passed from the electrodes 9 and 10 of the MR film 8 to the MR film 8 and at the same time the MR film 8 is reproduced.
Is magnetized in a predetermined direction, and a change in the resistance value of the MR film 8 caused by a change in the magnetization direction due to an external magnetic field may be detected as a voltage change. The same applies to the MR film 7.

FIG. 4 shows a change in resistance value of the two-layer vertical MR head of this example with respect to an external magnetic field. In the two-layer vertical MR head of this example, when the external magnetic field is zero, the angle formed by the sense current direction and the magnetization spin is 45 °, so the anisotropic magnetoresistive effect does not take the minimum value, Even if the external magnetic field is near zero, the resistance value changes greatly. In addition, in this two-layer vertical MR head, as a matter of course, the angle between the sense current direction and the magnetization spin changes due to the change in the direction of the magnetization spin due to the external magnetic field. Since the resistance effect changes, the curve showing the change in the resistance value is a dispersion type curve.

Furthermore, in the two-layer vertical MR head of this example, since the directions of the sense currents of the two-layer MR films are orthogonal to each other, the magnetic behavior is stabilized, and Good symmetry and high linearity.

Furthermore, comparing FIG. 4 with FIG. 10,
FIG. 4 has better linearity in the region where the external magnetic field is near zero, and in the MR head of this example, unnecessary higher-order distortion in the reproduced waveform is reduced as compared with the conventional MR head.

Therefore, in the two-layer vertical MR head of this example, it is possible to detect a minute magnetic field in the vicinity of zero external magnetic field with high sensitivity without forming a bias conductor. Further, in the two-layer vertical MR head of this example, since it is not necessary to form the bias conductor, it is not necessary to provide the wiring of the bias conductor and it is not necessary to provide the groove portion in the shield magnetic body, and the productivity is improved. .

In the above-mentioned two-layer vertical MR head, M
Although the direction of the sense current flowing in the R film is defined by the position where the electrode is formed, it may be defined by the following method.

That is, as schematically shown in FIG. 5 (only the MR film 8 is shown in FIG. 5), the electrodes 19 and 20 are connected to the side surfaces of the front and rear ends of the MR film 8. further,
On the MR film 8, one end is connected to the electrode 19 and the other end is M
The first conductive pattern 21a having a plane triangle arranged obliquely with respect to the longitudinal direction of the R film 8 and the second parallelogrammic plane parallel to the other end of the first conductive pattern 21a. Conductive pattern 21b, second conductive pattern 21b
A third parallel conductive parallelepiped conductive pattern 21c that is parallel to the third conductive pattern 21c, and a fourth planar triangle whose one end is parallel to the third conductive pattern 21c and the other end is connected to the electrode 20.
Forming a conductive pattern 21d.

Therefore, the sense current flowing between the electrodes 19 and 20 is the same as the first to fourth conductive patterns 21a, 21b,
21c, to flow along the 21d, so that the its direction is restricted in a diagonal direction of the MR films 8 as indicated by arrow S _8. Note that such a connection method is generally called a barber pole method.

Further, as schematically shown in FIG. 6 (only the MR film 8 is shown in FIG. 6), a planar square M is formed.
The R film 8 may be configured such that the corner portions facing each other in one diagonal direction are composed of the first and third members 8a and 8c having a planar triangle, and the remaining part is composed of the second member 8b. The first and third members 8a and 8c and the second member 8b are made of materials having the same magnetic characteristics and different conductivity, and the first and third members 8a and 8c are made of a relatively conductive material. The second material 8b is made of a low material, and the second member 8b is made of a material having a relatively high conductivity. Furthermore, in this state M
The electrodes 29 and 30 are connected to the side surfaces of the front and rear ends of the R film 8.

Then, the sense current flowing between the electrodes 29 and 30 selectively flows in the second member 8b having relatively high conductivity, so that the direction thereof is M as shown by an arrow S ₈ in the figure.
The R film 8 is restricted in the oblique direction.

Even if the MR element in which the direction of the sense current is regulated is used in this way, the same effect as that of the above-mentioned two-layer vertical MR head can be obtained.

[0043]

As is clear from the above description, in the magnetoresistive effect magnetic head of the present invention, a pair of shield magnetic bodies are arranged facing the magnetic recording medium facing surface with a predetermined interval. A magnetoresistive effect element sandwiched between and arranged in a direction substantially orthogonal to the surface facing the magnetic recording medium is constituted by two layers of magnetoresistive effect films laminated via an insulating layer,
The direction of the sense current of each magnetoresistive film is a direction inclined by approximately equal angles in mutually opposite directions with respect to the orthogonal direction.

The magnetization spins of the magnetoresistance effect film of the magnetoresistance effect type magnetic head having such a structure usually appear in the width direction of the magnetoresistance effect film, and the magnetization spins are orthogonal to the orthogonal direction. . That is, if the angle formed by the orthogonal direction and the sense current direction is θ, the angle formed by the magnetization spin and the sense current is 90 ° −θ. From this,
The sense currents of the two-layered magnetoresistive films are also inclined with respect to the magnetization spins in directions opposite to each other by substantially equal angles, and the sense current direction and the magnetization spins are not orthogonal to each other.

Therefore, even when there is no bias magnetic field and the external magnetic field is zero, the anisotropic magnetoresistive effect does not reach the minimum value, the resistance value does not reach the minimum value, and the external magnetic field is very small near zero. Even in a magnetic field, the change in the resistance value of the magnetoresistive film becomes large, and it is possible to detect a minute magnetic field in the vicinity of zero external magnetic field with high sensitivity.

Further, in the magnetoresistive head of the present invention, since it is not necessary to form the bias conductor, it is not necessary to provide the wiring of the bias conductor, and it is not necessary to provide the groove portion in the shield magnetic body, and the productivity is improved. Is improved.

In such a two-layer vertical magnetoresistive effect type magnetic head, it is energy-stable that the magnetization spins of the magnetoresistive effect film of the magnetoresistive effect element are in antiparallel state. There is.

Therefore, at this time, in the magnetoresistive effect type magnetic head of the present invention, the direction of the sense current of each magnetoresistive effect film is tilted by approximately 45 ° with respect to the orthogonal direction,
By making them substantially orthogonal to each other, the same applies to the magnetization spin, and the magnetic behavior of the magnetoresistive film is most stable.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an MR head to which the present invention is applied.

FIG. 2 is a plan view schematically showing an example of an MR film of an MR head to which the present invention is applied.

FIG. 3 is a schematic diagram showing a relationship between a sense current direction and a magnetization spin in a two-layer MR film of an MR head to which the present invention is applied.

FIG. 4 is a characteristic diagram showing the relationship between the strength of an external magnetic field and the resistance.

FIG. 5 is a plan view schematically showing another example of the MR film of the MR head to which the present invention is applied.

FIG. 6 is a plan view schematically showing still another example of the MR film of the MR head to which the present invention is applied.

FIG. 7 is a cross-sectional view schematically showing a conventional MR head.

FIG. 8 is a characteristic diagram showing an example of the relationship between the strength of an external magnetic field and the resistance.

FIG. 9 is a schematic diagram showing a relationship between a sense current and a bias current in a conventional MR head.

FIG. 10 is a characteristic diagram showing another example of the relationship between the strength of an external magnetic field and the resistance.

FIG. 11 is a schematic diagram showing a relationship between a magnetization spin and a sense current in a conventional MR head.

[Explanation of symbols]

 1, 2 Shield magnetic body 3 Magnetic recording medium facing surface 4, 5, 6 Insulating layer 7, 8 MR film 11 MR element

Claims (2)

[Claims] 1. A pair of shield magnetic bodies are arranged at a predetermined interval facing the magnetic recording medium facing surface, and a magnetoresistive effect element is provided between the shield magnetic bodies in a direction substantially orthogonal to the magnetic recording medium facing surface. In the magnetoresistive effect type magnetic head, the magnetoresistive effect element is composed of two layers of magnetoresistive effect films laminated via an insulating layer, and the direction of the sense current of each magnetoresistive effect film is A magnetoresistive effect magnetic head characterized by being tilted at substantially equal angles in mutually opposite directions with respect to an orthogonal direction. 2. The magnetoresistive effect type magnetic element according to claim 1, wherein the directions of the sense currents of the respective magnetoresistive effect films are inclined substantially 45 ° with respect to the orthogonal direction and are substantially orthogonal to each other. head.