JP3313795B2 - Magnetoresistive magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-resistance effect type magnetic head for performing magnetic recording by floating on a magnetic recording medium in a hard disk drive or the like, and more particularly to a magneto-resistance effect type magnetic head. This is an improvement in the shape of the element.

[0002]

2. Description of the Related Art In recent years, hard disk drives have been widely used as external recording devices for computers because of their demands for high-speed recording and high-speed reading and high-capacity recording. For this hard disk drive device, it is desired to realize a small and high capacity hard disk drive device in order to respond to recent miniaturization and light weight of a computer. It is desired to develop a magnetoresistive magnetic head using a magnetoresistive element as a magnetic head capable of obtaining high output without depending on the speed of the magnetic head.

A conventional magnetoresistive head will be described below. FIG. 4A is a diagram showing a configuration of a conventional magnetoresistive magnetic head. This magnetoresistive magnetic head is composed of a magnetoresistive element which performs a change in resistance value with respect to an external magnetic field. And a lead 2 for supplying a current to the magnetoresistive element for changing a change in resistance of the magnetoresistive element into a change in voltage.

The direction of the current flowing through the read portion of the magneto-resistance effect type magnetic head is the direction indicated by arrow 3 in FIG. The magnetic flux detector 1 of the magnetoresistive head is surrounded by the current a, and the width of the current inlet 8 and the width of the current outlet 9 are equal.

FIG. 5 is a perspective view of the magnetoresistive head constructed as described above. The element section of the magnetoresistive head has a configuration as shown in FIG. 6 when viewed from the surface of the magnetic recording medium. The magnetic flux detecting section 1 and the lead section 2 are connected via a nonmagnetic insulating layer 11. Magnetic shield 1
It is installed between 0.

FIG. 7 shows the actual operation of the magneto-resistance effect type magnetic head having the above configuration. First, on the medium of the magnetic recording medium 4, unidirectional magnetization as indicated by the internal magnetization direction 7 of the medium is recorded as data. The magnetic flux 6 external to the medium is emitted into the air from the direction of reversal of the recorded magnetization, and the magnetic flux detecting unit 1 of the magnetoresistive element passes over the medium magnetic field formed by this.

At this time, a change in the resistance value of the magnetic flux detector 1 corresponding to the medium magnetic flux is obtained as a voltage change by flowing a current through the lead 2. FIG. 4 shows an output change when the magnetoresistive head is moved right and left in the track width direction.
(A). As can be seen from FIG. 4A, when the magnetoresistive head is moved to the left or right, the output decreases rapidly and moves to the minus side. When it moves, it shows a constant output value and then shows a decrease in output, and the output characteristic in the track width direction is symmetrical.

The operation of the conventional magnetoresistive head constructed as described above will be described below.
In the enlarged view of the magnetoresistive element section as shown in FIG. 8, consider the magnetic flux detecting section capabilities at points a and b when the magnetic recording medium 4 generates off-track and the like with respect to the magnetoresistive element section. .

The initial magnetization directions at point a and point b have a bias magnetic field added to generate a linear output with respect to an external magnetic field and already have an angle of θ with the current direction 3; The directions of the magnetic field at points b and b are in the directions of Ma and Mb. The direction of the magnetic flux from the magnetic recording medium 4 is in the directions of Ba and Bb, and contributes as vector magnetic flux components of Ba and Bb at points a and b.

At this time, the resistance ρ of the magnetoresistive element is given by ρ = △ ρ · cos 2θ using the angle θ between the current and the magnetization vector and the resistance change rate △ ρ. Therefore,
Assuming that the angle between the current 3 and Ba at the point a is θa and the angle between the current 3 and Bb at the point b is θb, the resistance change at the point a is ρ = △ ρ (cos2θa−cos2θ),
The resistance change amount at point b is ρ = △ ρ (cos2θb-cos
2θ). On the other hand, at point b, the angle between Bb and Mb is almost parallel and θb ≒ θ, so that no output is obtained in the magnetoresistive head.

On the other hand, as shown in FIG. 9, when positioned at the right end of the magnetic recording resistance element portion, the direction of the magnetic flux from the magnetic recording medium 4 is: The head outputs in this case correspond to the angle between Ba and Ma and the angle between Bb and Mb at points a and b.

Therefore, a slight output difference occurs between the point a and the point b. Therefore, the detection capabilities at the left and right ends of the magnetoresistive element are different, resulting in output characteristics that are asymmetrical in the track width direction as shown in FIG. 4B.

[0013]

As is apparent from the above description, the above-described structure of the conventional magnetoresistive magnetic head has an output characteristic in the track width direction that is asymmetrical in the left-right direction.
An output cannot be obtained depending on the direction of displacement of the center of the head, so that the center of the head output and the center of the shape of the magnetoresistive element cause a positional difference. Therefore, when a control signal for the track position is obtained from the output of the magnetoresistive element, a difference occurs between the control signal obtained when the signal is shifted to the right and the control signal obtained when the signal is shifted to the left. There was a problem that it would.

In view of the above problems, an object of the present invention is to provide a magnetoresistive head capable of obtaining a symmetrical output during off-track.

[0015]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a magnetoresistive element having a magnetoresistive element shape in which the width of a magnetic flux detecting portion is narrower near a current outflow portion than in a current inflow portion. This is a configuration of a type magnetic head.

[0016]

Therefore, in the magnetoresistive head according to the present invention, the width of the magnetic flux detecting portion is narrower near the current outflow portion than in the current inflow portion, so that the width is smaller near the current outflow portion. For this reason, it is possible to obtain an output even when the detection unit is displaced in either the left or right direction, and to provide an effect that the output characteristics in the track width direction of the magnetoresistive head are made symmetrical. It is. This enables the shape center of the element to be aligned with the output center, and constitutes a magnetoresistive head having symmetric output characteristics during off-track.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1A shows a magnetoresistive head according to an embodiment of the present invention. In FIG. 1 (a), a magnetic flux detecting section 1 composed of a magnetoresistive element exhibiting a change in resistance with respect to an external magnetic field is provided, and these are generally made of an Fe-Ni alloy or a Co-Ni alloy exhibiting a magnetoresistive effect. Is done. This magnetoresistive element is formed by a vacuum film forming method such as a vacuum evaporation method or a sputtering method. The film is formed to have a particularly thin film thickness of about 500 ° in order to suppress the demagnetizing field and improve the output.

In FIG. 1A, a lead portion 2 for supplying a magnetic resistance element is provided.
In general, gold, aluminum, or the like having a low electric resistance is used. Tungsten is used as the lead portion 2 particularly when electromigration of electric diffusion is suppressed. When forming the lead 2,
In general, a vacuum deposition method such as a vacuum deposition method, a sputtering method, and a CVD method is employed. These lead portions 2 are formed by forming a protective film of an arbitrary shape by a photoengraving technique (photolithography technique) and processing the film by chemical etching or physical etching.

Here, the characteristic point of the magnetoresistive head according to the present invention is that, as shown in FIG. 1A, the element width of the current inflow section 8 is smaller than that of the current inflow section 8b at the current outflow section 9b. It is narrower than that.

The operation of the magneto-resistance effect type magnetic head of the embodiment constructed as described above will be described below. In the enlarged view of the magnetoresistive element portion as shown in FIG. 3, consider the magnetic flux detecting ability at points a and b when the magnetic recording medium 4 has an off-track with respect to the magnetoresistive element portion.

First, a bias magnetic field is added to the initial magnetization direction at point a in order to generate a linear output with respect to an external magnetic field, and the magnetization direction already has an angle of θ with the current direction 3. The direction of magnetization at point a is oriented in the direction of Ma.

However, since the width at point b is narrow as shown in FIG. 1 (a) b, the direction of the current is in the direction indicated by i at point b. Therefore, the direction of the magnetization at point b obtained by applying the bias magnetic field is Mb.
Therefore, the magnetic fluxes Bb and Mb from the magnetic recording medium 4 have an angle to each other, and the width of the current inflow portion 8 and the width of the current outflow portion 9 are formed equal in the conventional magnetoresistance effect type magnetic head. At point b, since the angle between Bb and Mb is almost parallel and θb ≒ θ, an output cannot be obtained at point b. However, an output can be obtained by using the shape of the present invention. Can be done.

Further, as shown in FIG. 4, when the magnetic recording medium 4 is located at the right end of the magnetoresistive element portion, the direction of the magnetic flux from the magnetic recording medium 4 is considered in consideration of the magnetic flux detection capability at points a and b. Is the direction of Ba and Bb. Therefore, these are the angle between Ba and Ma at points a and b, and B
An output corresponding to the angle between b and Mb is generated. Therefore,
Although there is an output difference between point a and point b, an output can be obtained for each.

As described above, according to this embodiment, the magnetoresistive effect type magnetic head has a magnetoresistive element shape in which the width of the magnetic flux detecting portion is smaller in the vicinity of the electric outflow portion than in the electric inflow portion. As shown in FIG.
A magnetoresistive head having a symmetrical output characteristic in the track width direction can be obtained. Accordingly, when a track position control signal is obtained from the output of the magnetoresistive element, an output can be obtained both in the case of shifting to the right and in the case of shifting to the left. Is generated, and the shape center of the element can be aligned with the output center.

[0025]

As described above, according to the present invention, the width of the magnetic flux detecting portion is smaller in the vicinity of the current outflow portion than in the current inflow portion, so that the magnetic head has a magnetoresistive element shape. Therefore, the reproduction capability of the left and right ends of the magnetoresistive effect element can be made equal, whereby the present invention has an effect that the output characteristics in the track width direction are symmetric. A magnetoresistive head can be realized.

Accordingly, since the output characteristics in the track width direction are symmetrical, the output of this magnetoresistive element can be obtained both when the track position shifts to the right during off-track and when the track position shifts to the left. In any case, a control signal for controlling the displacement can be issued, and the shape center of the element can be aligned with the output center.

[Brief description of the drawings]

1A is a configuration diagram of a magnetoresistive magnetic head according to an embodiment of the present invention, FIG. 1B is an output characteristic diagram of a symmetrical track width direction obtained by the present invention,

FIG. 2 is a diagram showing the output of each unit when a magnetic recording medium is located at the left end of a magnetic flux detection part in the element shape of the present invention;

FIG. 3 is a diagram showing the output of each unit when a magnetic recording medium is present at the right end of a magnetic flux detection part in the element shape of the present invention;

FIG. 4A is a configuration diagram of a magnetoresistive effect type magnetic head according to a conventional example, FIG.

FIG. 5 is a configuration diagram of a conventional magnetoresistive head;

FIG. 6 is an external view of a magnetoresistive head according to a conventional example as viewed from a magnetic recording medium surface.

FIG. 7 is a diagram showing an operation of the magnetoresistive head;

FIG. 8 is a diagram showing the output of each unit when the magnetic recording medium is at the left end of the magnetic flux detection unit;

FIG. 9 is a diagram showing the output of each unit when a magnetic recording medium is at the right end of the magnetic flux detection unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic flux detection part 2 Lead part 3 Current direction 4 Magnetic recording medium 5 Magnetic flux in a magnetoresistive element 6 Medium external magnetic field 7 Medium internal magnetization direction 8 Current inflow part 9 Current outflow part 10 Magnetic shield 11 Insulation layer

Claims (1)

(57) [Claims] 1. A magnetoresistive head according to claim 1, wherein the width of the magnetic flux detecting portion is smaller in the vicinity of the current outflow portion than in the current inflow portion.