JPH07201015A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To obtain readout output from a magneto-resistance effect type head in stable state by making a sense current flowing current terminal function to increase a vertical bias for a magneto-resistance layer and to stabilize a horizontal bias for a horizontal bias layer. CONSTITUTION:As shown in 'down', 'up' in circles, the sense current flows from the current terminal 51 on one side to a paper sheet downward, and after passing the horizontal bias layer 3 and the magneto-resistance layer 1, it flows from the current terminal 52 on the other side upward. A magnetic field generated by the sense current is added on a bias magnetic field in the same direction as the bias magnetic field by two domain stabilizing layers 21, 22 as shown in the circles on which arrowheads are attached, which increase the bias magnetic field. In such a way, the sense current supplied from the current terminals 51, 52 to the magneto-resistance layer 1 functions so as to increase the vertical bias to the magneto-resistance layer 1 and also, to stabilize the horizontal bias to the horizontal bias layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head for reading a magnetic recording recorded by perpendicular magnetization on a magnetic recording medium such as a magnetic disk or a magnetic tape.

[0002]

2. Description of the Related Art FIGS. 4 (a) and 4 (b) are views showing an example of a magnetic disk device to which a magnetoresistive head according to the present invention can be applied. FIG. 4 (a) is a plan view with a cover removed. FIG. 1B is a sectional view.

The magnetic disk device is sealed by a cover 10 and a base 11. The spindle 13 is rotatably attached to the base 11, and the spindle 13
It is driven to rotate by a spindle motor built into the.

Magnetic disks 12 and annular spacers 20 are alternately inserted in the spindle 13, whereby a plurality of magnetic disks 12 are attached at a predetermined interval. In addition, the disk clamp 14 is attached to the spindle 13
Each magnetic disk 12 is fixed by being sandwiched between the annular spacers 20, 20 by screwing.

The actuator 16 is rotatably erected on the base 11, and a pair of spring arms 18 are attached to each arm 17 so as to be biased in a direction away from each other.

At the tips of these spring arms 18,
A recording / reproducing head 15 for writing information on or reading recorded information from each magnetic disk 12 is attached.

At the time of starting the apparatus, as the spindle 13 rotates, each of the attached magnetic disks 12 rotates at, for example, 4
The recording / reproducing head 15 which is rotating at 400 rpm and brought into contact with the magnetic disk 12 is about 0.13 on the magnetic disk 12.
Ascend to μm.

The arm 17 is rotated by the driving of the voice coil motor 18, and the recording / reproducing head 15 attached to the tip of the spring arm moves in the radial direction of the magnetic disk 12 to write information in the data area of the magnetic disk 12. Read or read.

FIG. 5 (a) is an enlarged view of the recording / reproducing head 15 for performing recording / reproducing as described above, and FIG. 5 (b) shows a main portion by cutting / enlarging a part of the element portion P thereof. It is a figure.

The recording / reproducing head 15 comprises a recording head and a reproducing head, and these heads are formed on a ceramic head substrate 21 by a thin film technique.

The recording head comprises a coil 31 and a core 32, and serves as an inductive head for magnetic recording.
The reproducing head is configured as a magnetoresistive reproducing head including a magnetoresistive (MR) element 30 and a terminal 33 for supplying a sense current to the MR element 30.

A magnetic shield 34 for preventing interference between the recording head and the reproducing head is provided between the recording head and the reproducing head, and the recording / reproducing head performs recording / reproducing. The recording track to be performed is indicated by 40.

Further, 23A and 23B in FIG. 5A are lead wire connecting terminals connected to the recording head formed on the head base 21, and 25A and 25B are connected to the reproducing head. There is a terminal portion for connecting the lead wire. These are connected to the control unit via an FPC by a lead wire (not shown).

FIG. 6A shows a cross section of a conventional recording / reproducing head formed by a thin film technique.
This corresponds to the cross section taken along the line A. This recording / reproducing head has an insulating layer provided on a ceramic head substrate.
Shield layer-insulating layer-MR element including magnetoresistive (MR) layer and soft adjust (SAL) layer-terminal layer-insulating layer forms a reproducing head portion, and a shield layer-
The recording head is composed of the coil layer, the insulating layer, the magnetic pole layer, and the protective layer.

FIG. 2B is a view of the MR element and the terminal layer of the reproducing head portion taken out from the top of FIG. 1A, and in FIG. 2B, the MR element 30 and the terminal 33 are shown. However, two terminals are provided on one surface of the MR element 30.

FIG. 7 is a conceptual view showing an example of a conventional magnetoresistive head without the protective layer covering the entire surface thereof. FIG. 7A is a sectional view and FIG. 7B is a perspective view. FIG. 3C is a diagram showing the principle of reading the perpendicular magnetization.

The magnetoresistive layer 1 is formed as a thin film formed by sputtering a material whose resistance value changes by magnetic force, such as permalloy, and the magnetic domain stabilizing layers 2 ₁ , 2
₂ is a BCS layer (boundary co-layer) formed of an antiferromagnetic material such as iron-manganese and in a substantially magnetized state.
A magnetic bias in the width direction of the recording track (hereinafter referred to as longitudinal bias) is applied to the magnetoresistive layer 1.

The lateral bias layer 3 is made of a magnetized magnetic material such as nickel-iron-rhodium or nickel-iron-chromium.
er), a magnetic bias (hereinafter referred to as a lateral bias) in the direction perpendicular to the magnetic bias of the magnetic domain stabilizing layers 2 _1, 2 ₂ is given to the magnetoresistive layer 1. It is provided for this purpose.

As another method of generating the lateral bias, a shunt bias layer made of a conductive material such as Ti that generates a magnetic field by passing an electric current can be used instead of the soft adjusting layer.

The lateral bias layer referred to in the present invention is a layer provided for giving a lateral bias, such as the soft adjusting layer or the shunt bias layer.

The magnetic shield layer 4 usually provided is made of, for example, tantalum or titanium, and magnetically shields the magnetoresistive layer 1 and the lateral bias layer 3 with a current flowing through the magnetoresistive layer 1. The magnetized lateral bias layer 3 makes the magnetization direction of the magnetoresistive layer 1 upside down with respect to the magnetization direction of the lateral bias layer 3 to enable reading from the recording medium.

The magnetoresistive layer 1, the magnetic domain stabilizing layer 2, the lateral bias layer 3 and the magnetic shield layer 4 are usually all formed by a film forming technique such as sputtering.

As described above, the magnetic resistance layer 1 is provided with the longitudinal bias by the magnetic domain stabilizing layer 2 and the lateral bias by the magnetic shield layer M, and the reading of the perpendicular magnetization recording on the recording medium is as follows. As shown in FIG. 7 (c), the vector change of the magnetic field that changes according to the magnetization state of the magnetic recording track Tr on the magnetic recording medium is read as the change of the sense current flowing in the magnetoresistive layer 1. Is.

The current terminals 5 ₁ and 5 ₂ are terminals for flowing the above-described sense current through the magnetoresistive layer 1, and are, for example, 5
A recording track Tr on a magnetic recording medium of μm or less
Are provided at intervals equal to the width of.

In such a conventional magnetoresistive head, as shown in FIG. 7A, the region sandwiched between the current terminals 5 ₁ and 5 ₂ of the magnetoresistive layer 1 is the magnetic domain stabilizing layer. Two
Although it is magnetized by the magnetic field from, if this region is not accurately magnetized and is divided into a plurality of magnetic domains, the resistance of the magnetoresistive layer 1 changes randomly with respect to the change of the magnetic field from the magnetic recording medium, As a result, the reading is not completely performed or noise is generated, which adversely affects the reading result. Therefore, the magnetoresistive layer 1 is made as a single magnetic domain as possible (the magnetic domains are aligned in one direction). Is desirable.

Therefore, when the magnetoresistive layer of this magnetoresistive head is formed by the film forming technique as shown in FIG. 5, care should be taken to make the formed magnetoresistive layer into a single magnetic domain as much as possible. However, the magnetic domain may change depending on the process environment, the use environment, etc., and it is difficult to form a single magnetic domain completely.

Further, in the magnetic recording / reproducing apparatus, in order to confirm the result of writing on the recording medium, immediately after writing on the recording medium, reading is performed from this recording medium to write the written data and the read data. Although verification is performed to compare and compare the data, it is necessary to read the data immediately after writing, so that a magnetoresistive head adjacent to the magnetic recording head is provided immediately adjacent to the magnetic recording head. Since it is provided, the magnetic flux leaking from the magnetic head for writing may destroy the single magnetic domain of the magnetoresistive layer of the magnetoresistive head.

In order to make the magnetoresistive layer 1 into a single magnetic domain as described above, it is necessary to apply a magnetic field as strong as possible to this domain domain. For this reason, the magnetic domain stabilizing layers 2 ₁ and 2 ₂ are provided. However, it is difficult to apply a strong magnetic field to the two magnetic domain stabilizing layers 2 ₁ and 2 ₂ since they are formed with a gap corresponding to the width of the recording track Tr. Magnetization by only ₁ and 2 ₂ is not sufficient to make the magnetoresistive layer 1 into a single magnetic domain.

Further, Fe-Mn used as the material of the magnetic domain stabilizing layer 2 is a material which is very easily corroded, and is oxidized and corroded just by contact with air during manufacturing of the magnetoresistive head. The magnetic domain stabilizing layers 2 ₁ and 2 ₂ need to be covered with the current terminals 5 ₁ and 5 ₂ and an insulating layer (not shown) at all times.

On the other hand, with respect to the lateral bias layer such as the SAL layer, the magnetic domain changes depending on the manufacturing process and the environment of use, and if the magnetic domains do not become a single magnetic domain and are disjointed, a stable read output cannot be obtained. It is desirable that this lateral bias is also stabilized by forming a single magnetic domain.

As described above, in the conventional magnetoresistive head, the magnetic domain stabilizing layer does not sufficiently make the magnetic resistance layer into a single magnetic domain, and the lateral bias layer is not sufficiently stabilized, so that noise is generated. There is a problem in that it is likely to occur and the reading characteristic of information from the recording medium is not stable.

[0032]

The object of the present invention is to increase the strength of the longitudinal bias magnetic field applied to the magnetoresistive layer and stabilize the transverse bias, so that the information recorded by perpendicular magnetization on the recording medium is obtained. To provide a magnetoresistive head having improved and stabilized read characteristics.

[0033]

The principle of the present invention is conceptually
As shown in FIG. 1 shown, the magnetoresistive layer 1 and the magnetic resistance
First magnetic domain stabilizing layer 2 provided on the anti-layer 1₁And above
The first magnetic domain stabilizing layer 2 is formed on the same surface of the magnetoresistive layer 1.
₁From the time corresponding to the width of the recording track on the magnetic recording medium
Second magnetic domain stabilizing layer 2 provided with a gap₂And above
The first magnetic domain stabilizing layer 2 is formed on the same surface of the magnetoresistive layer 1.
₁And the second magnetic domain stabilizing layer 2₂Magnetic shield provided between
Shielding layer 4 and the first magnetic domain stabilizing layer 2₁And the second magnetic domain cheap
Normalization layer 2 ₂And a lateral bias layer 3 covering the magnetic shield layer 4,
The first magnetic domain stabilizing layer 2 is provided via the lateral bias layer 3.
₁The first current terminal 5 provided at a position facing the₁When,
The second magnetic domain stabilizing layer 2 via the magnetoresistive layer 1₂
Second current terminal 5 provided at a position facing the₂And set
A magnetoresistive head was constructed.

[0034]

In the present invention, as indicated by circles "bottom" and "top" in FIG. 1, the sense current from _one current terminal 5 ₁ flows downward with respect to the plane of the drawing, and the lateral bias layer 3 and after passing through the magneto-resistive layer 1, it flows from the other current terminal 5 ₂ upward.

The magnetic field generated by this sense current is
As shown by the circle with an arrow in FIG. 1, the bias magnetic field is added to the bias magnetic field in the same direction as the bias magnetic field by the two magnetic domain stabilizing layers 2 ₁ and 2 ₂ , and as a result, the bias magnetic field is strengthened. Become.

Therefore, these magnetic domain stabilizing layers 2 ₁ , 2
_The magnetoresistive layer 1 in the region sandwiched by ₂ has a strong magnetic field obtained by adding the magnetic fields from the magnetic domain stabilizing layers 2 ₁ and 2 ₂ and the magnetic field generated by the sense current flowing through the current terminals 5 ₁ and 5 _2. Is applied, the magnetoresistive layer 1 in the region between the current terminals is made into a single magnetic domain.

The portion where the magnetoresistive layer 1 and the lateral bias layer 3 are in direct contact is made of, for example, Ta or Ti, and the magnetoresistive layer 1 and the lateral bias layer 3 are formed.
And a magnetic shield layer for magnetically shielding and.

Further, the magnetic field due to the sense currents flowing through these current terminals 5 ₁ and 5 ₂ has a vertical component in the drawing orthogonal to the lateral bias layer 3, so that the lateral bias layer 3 is made into a single magnetic domain. Do.

Further, as the lateral bias layer 3, as described in the conventional example, a soft adjusting layer,
Alternatively, a shunt bias layer or the like can be used.

Thus, according to the present invention, the current terminal 5
_The sense currents supplied from ₁ , 5 ₂ to the magnetoresistive layer 1 function to strengthen the longitudinal bias for the magnetoresistive layer 1 and stabilize the lateral bias for the lateral bias layer. Then, the read output from the magnetoresistive head can be obtained in a stable state.

[0041] Incidentally, the electrical connection between the current terminals 5 ₁ and the magnetoresistive layer 1, the current terminal 5 ₁ - transverse bias layer 3 domain stabilizing layer 2 ₁ - transverse bias layer 3 becomes magnetoresistive layer 1 A resistor will be inserted in the sense current path.

However, since the value of the sense current is extremely small, the read output is not affected by the resistance in practice, and the ratio of the resistance value of the magnetoresistive layer 1 to the resistance value of the lateral bias layer 3 is small. Since it is on the order of 2: 8, the magnetoresistive layer 1 is not electrically bypassed by the lateral bias layer 3.

[0043]

FIG. 2 shows an embodiment in which the magnetoresistive head according to the present invention is applied to a recording / reproducing head formed by the thin film technique as described above. FIG. 2 (a) shows the conventional example. It corresponds to FIG. 6 (a), and is different from the above-mentioned conventional example in that a pair of terminals is provided on both sides of the MR element.

That is, in this recording / reproducing head, an insulating layer provided on a ceramic head substrate-a shield layer-an insulating layer having one terminal provided on the upper surface-a magnetoresistive (MR) layer,
MR element including soft adjust (SAL) and longitudinal bias (BCS) layers--an insulating layer having one terminal provided on the lower surface forms the reproducing head portion according to the present invention.

The recording head composed of a shield layer, a coil layer, an insulating layer, a magnetic pole layer and a protective layer provided thereon is the same as in the conventional example.

FIG. 2 (b) shows the conventional example shown in FIG.
It corresponds to (a) and is different from the above-mentioned conventional example in that a pair of terminals are arranged on the front side and the rear side of the MR element, respectively.

FIG. 3 is a perspective view showing an embodiment of the present invention and has the same structure as that described with reference to FIG. Although the insulating layer is provided so as to cover the entire configuration shown in the figure, it is shown in the state where the insulating layer is removed in this figure, although the insulating layer is provided.

The magnetic shield layer 4 is made of a magnetic material such as tantalum or titanium, which is provided to prevent the magnetoresistive layer 1 and the lateral bias layer 3 from being magnetically coupled to each other. This is the same as the description of the conventional example. Since the other operations are the same as those described above based on the principle diagram of FIG. 1, detailed description of this embodiment will be omitted.

[0049]

As described above, according to the present invention, the sense current flowing through the current terminal enhances the longitudinal bias for the magnetoresistive layer and stabilizes the lateral bias for the lateral bias layer. As a result, it is possible to obtain a particular effect that the read output from the magnetoresistive head can be obtained in a stable state.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a sectional view showing a configuration of an embodiment of a recording / reproducing head in which the present invention is implemented by a thin film technique.

FIG. 3 is a perspective view showing an embodiment of the present invention.

FIG. 4 is a diagram showing an example of a magnetic disk device to which the head of the present invention can be applied.

5 is a perspective view showing a configuration of a recording / reproducing head portion of the magnetic disk device shown in FIG.

FIG. 6 is a cross-sectional view showing a configuration of a conventional recording / reproducing head manufactured by a thin film technique.

FIG. 7 is a sectional view showing an example of a conventional magnetoresistive head, a perspective view, and a diagram for explaining the operating principle.

[Explanation of symbols]

1 Magnetoresistive layer 2 ₁ , 2 ₂ Magnetic domain stabilizing layer 3 Transverse bias layer 4 Magnetic shielding layer 5 ₁ , 5 ₂ Current terminal Tr Recording track

Claims (2)

[Claims] 1. A magnetoresistive layer (1) and the magnetoresistive layer (1)
The first magnetic domain stabilization layer (2 ₁) And the above magnetic resistance
The first magnetic domain stabilizing layer (2) is formed on the same surface of the layer (1).₁) From
An interval corresponding to the width of the recording track on the magnetic recording medium is separated.
Second magnetic domain stabilization layer (2₂) And the magnetic resistance
On the same surface of the anti-layer (1), the first magnetic domain stabilization layer (2₁)When
Second magnetic domain stabilization layer (2₂) Magnetic shielding layer provided between
(4) and the first magnetic domain stabilization layer (2₁), The second magnetic domain is stable
Chemical layer (2₂) And a lateral bias layer (3) over the magnetic shield layer (4)
And the first magnetic domain stabilization via the lateral bias layer (3)
Chemical layer (2₁) The first current terminal (5
₁) And the second magnetic domain stable through the magnetoresistive layer (1).
Chemical layer (2₂) The second current terminal (5
₂), And a magnetoresistive head.
De. 2. The magnetoresistive head according to claim 1, wherein the lateral bias layer is a soft adjusting layer or a shunt bias layer.