JPH06203338A - Magneto-resitance effect type head - Google Patents

Abstract

PURPOSE:To provide the structure of the MR head which is controllable in the shunt ratio of sense current and bias current after film formation as the MR head having an MR element, a pair of electrodes for detecting a resistance change of the MR element and a shunt layer for impressing bias magnetic fields to the MR element. CONSTITUTION:A pair of the electrode layers 5, 6 for electrically connecting the shunt layer 4 in parallel to the MR element 1 are formed in superposition on both ends of the shunt layer 4. The respective electrode layers 5 are interposed with plural pieces of electrode lines 51 parallel with each other with both junctures are interposed between the juncture to the shunt layer 4 and the juncture to the electrodes 2. The shunt ratio of the current flowing in the MR element 1 and the shunt layer 4 is finely adjusted by the breakage of a required number of the electrode lines 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head (hereinafter referred to as MR head) including a magnetoresistive effect element (hereinafter referred to as MR element).

[0002]

2. Description of the Related Art In recent years, in order to cope with higher densities and miniaturization of various signal recording / reproducing devices such as hard disk devices and VTRs (video tape recorders), development of MR heads having excellent reproduction output characteristics is progressing. .

The MR head uses an MR element whose resistance value changes depending on the angle formed by the direction of current and the direction of magnetization, and detects a change in the signal magnetic field as a resistance change. The reproduction output voltage of the MR head is the medium-head. It has the feature that it does not depend on the relative speed between.

The basic structure of a conventional MR head is shown in FIG. A shunt layer (43) is formed to cover the surface of the MR element (12), and a pair of electrodes (22) and (22) are formed on the surface of the shunt layer (43) with a predetermined track width T therebetween. ing.

The MR element (12) is patterned so as to have an easy axis of magnetization in its longitudinal direction (left and right direction in FIG. 5), and its end face is exposed at the contact surface with the recording medium (6) to give a signal. Detect magnetic field. MR element according to the signal magnetic field from the recording medium (6)
When the direction of magnetization of (12) changes, the MR element
The resistance value of (12) changes, and the change of the resistance value changes the pair of electrodes (2
2) It is detected as a voltage change by (22).

The current flowing through the electrode (22) is shunted to the MR element (12) and the shunt layer (43) as a sense current and a bias current, respectively. Here, the bias current plays a role of linearizing the reproduction output of the MR head with respect to the signal magnetic field, and the bias magnetic field applies the bias magnetic field to the MR element (12) in the film thickness direction. This bias method is known as the shunt bias method.

[0007]

In the MR head adopting the conventional shunt bias method, the shunt ratio of the sense current and the bias current is selected by selecting the specific resistance and film thickness of the materials of the MR element and the shunt layer. Have control. However, in general, inhomogeneities such as grain boundaries, lattice defects, and inclusion of impurities occur in the MR element and the shunt layer due to incomplete film formation, and this appears as nonuniformity in resistivity. Become. As a result, there is a problem that the shunt ratio of the sense current and the bias current varies for each MR head, and the desired head performance cannot be obtained.

An object of the present invention is to provide an MR head capable of adjusting the shunt ratio of the sense current and the bias current after film formation.

[0009]

In the first MR head according to the present invention, as shown in FIG. 1, a pair of electrodes for electrically connecting the shunt layer (4) in parallel to the MR element (1). Layers (5) and (5) are formed by overlapping on both ends of the shunt layer (4), and each electrode layer (5) includes a connection portion with the shunt layer (4) and a connection portion with the electrode (2). A plurality of electrode strips (51) that are parallel to each other are interposed between the connecting portions. In addition, in the second MR head according to the present invention, as shown in FIG. 3, a plurality of MR heads in parallel with the connecting portion with the pair of electrodes (21) and (21) are provided in the central portion of the shunt layer (41). The shunt strip (42) is intervening.

[0010]

In the manufacturing process of the first MR head,
With the electrodes (2) and (2) being formed on both ends of the MR element (1), the resistance of the MR element alone is evaluated. Then MR
A shunt layer (4) and electrode layers (5) and (5) are formed on the element (1) and the electrodes (2) and (2), and in this state, the combined resistance of the MR element and the shunt layer is evaluated. Furthermore, the resistance of the shunt layer alone is analyzed based on the above two evaluations, and the shunt ratio of the sense current and the bias current is obtained. At this time, if the optimum diversion ratio is not obtained, the required number of electrode strips (51) is broken by processing using a laser beam or the like, and the resistance value of the electrode layer (5) is changed to obtain the optimum value. Adjust to the diversion ratio.

In the manufacturing process of the second MR head, the resistance of the MR element alone is evaluated in a state where the electrodes (21) and (21) are formed on both ends of the MR element (11). afterwards,
The shunt layer (41) is formed on the MR element (11) and the electrodes (21) and (21), and in this state, the combined resistance of the MR element and the shunt layer is evaluated. Furthermore, the resistance of the shunt layer alone is analyzed based on the above two evaluations, and the shunt ratio of the sense current and the bias current is obtained. At this time, if the optimum diversion ratio is not obtained, the required number of shunt strips (42) is broken by processing using a laser beam or the like, and the optimum value is obtained by changing the resistance value of the shunt layer (41). Adjust to the diversion ratio.

[0012]

According to the present invention, by splitting the electrode strip (51) of the electrode layer (5) or the shunt strip (42) of the shunt layer (41) after film formation, the shunt current of the sense current and the bias current is divided. Since the ratio can be adjusted, an MR head having desired performance can be obtained regardless of incomplete film formation.

[0013]

EXAMPLES MR head shown in the first embodiment FIG. 1, a pair of electrodes stacked on both ends of the MR element (1) which is patterned in the rectangle (2) (2) is formed, the electrodes (2) By the interval T of (2), the track width on the contact surface with the recording medium (6) is regulated to a predetermined value. An insulating layer is formed on the MR element (1) and the electrodes (2) and (2).
A shunt layer (4) is formed through (3), and the shunt layer is formed.
A pair of electrode layers (5) and (5) are formed so as to cover both ends of (4) and both ends of the insulating layer (3).

A plurality of electrode strips (51) extending in the track width direction are formed in each electrode layer (5) by providing a plurality of slits in the overlapping portion with the electrodes (2). Therefore, the necessary number is broken (52) as shown in FIG. 2 by subjecting the electrode strip (51) to laser processing, and the resistance value of the electrode layer (5) is changed to thereby divide the sense current and the bias current. Can be adjusted. The shape and size of the electrode strips (51) are determined according to the accuracy of the diversion ratio to be achieved.

In the MR head, the MR element (1)
The resistance of the shunt layer (4) is much larger than the resistance of the electrode layer (5), and the resistance change of the entire head due to the breakage of the electrode strip (51) of the electrode layer (5) is small. By breaking the strip (51), the shunt ratio of the sense current and the bias current can be finely adjusted. Further, the breaking of the electrode strips (51) by laser processing can be performed separately for a plurality of MR heads formed in the same wafer, so that a single wafer can be used for various diversion ratios depending on the purpose. It is possible to make an MR head.

Second Embodiment In the MR head shown in FIG. 3, an insulating layer (31) having a predetermined track width T is formed on the MR element (11), and the insulating layer (31) is sandwiched therebetween. A pair of electrodes (21) on each side
(21) is formed so as to cover both ends of the MR element (11).
In the upper part of the MR element (11), a shunt layer (41) is formed across both electrodes (21) (21), and by providing a plurality of slits in the central portion of the shunt layer (41), A plurality of shunt strips (42) extending in the track width direction are formed.

Therefore, the resistance value of the shunt layer (41) is changed by subjecting the shunt strips (42) to laser processing to break the required number, whereby the MR element (11) and the shunt layer (4) are changed.
It is possible to adjust the diversion ratio of the current flowing in 1).

Particularly in the MR head, the MR element (1
Since the insulating layer (31) is interposed between 1) and the shunt layer (41), the shunt current at the interface between the MR element (11) and the shunt layer (41) is stable, and the shunt current of the sense current and the bias current is shunted. The accuracy of the ratio can be improved. The lower part of the shunt layer (41) is the insulating layer (3
Since it is 1), laser processing becomes easy.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims. For example, as shown in FIG. 4, the insulating layer (31) in the MR head of the second embodiment can be omitted.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an MR head according to the present invention.

FIG. 2 is a perspective view showing a state in which a shunt ratio of a sense current and a bias current is adjusted.

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

FIG. 4 is a perspective view showing still another embodiment.

FIG. 5 is a perspective view showing a main part of a conventional MR head.

[Explanation of symbols]

 (1) MR element (2) Electrode (3) Insulating layer (4) Shunt layer (5) Electrode layer (51) Electrode strip (6) Recording medium

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

The current flowing through the electrode (22) is shunted to the MR element (12) and the shunt layer (43) as a sense current and a bias current, respectively. Here bias current plays a role of linearized reproduction output of the MR head with respect to the signal magnetic field, the in-plane vertical of the MR element (12) by the bias current
A bias magnetic field is applied in the direction (direction perpendicular to the recording medium (6)) . This bias method is known as the shunt bias method.

Claims (2)

[Claims] 1. A magnetoresistive effect element (1) and a pair of electrodes (2) for detecting a resistance change of the magnetoresistive effect element (1).
A magnetoresistive effect head comprising (2) and a shunt layer (4) for applying a bias magnetic field to the magnetoresistive effect element (1), comprising: A pair of electrode layers to electrically connect (4) in parallel (5)
(5) is formed by connecting both ends of the shunt layer (4) and both electrodes (2) and (2), and each electrode layer (5) has a connection portion with the shunt layer (4) and an electrode ( A plurality of electrode strips (51), which are parallel to each other, are interposed between the connecting portions with 2) and the required number of electrode strips (51) are broken, so that the magnetoresistive effect element (1) And a shunt layer (4) capable of adjusting the diversion ratio of the current flowing through the magnetoresistive head. 2. A magnetoresistive effect element (11) and a pair of electrodes (21) (2) for detecting a resistance change of the magnetoresistive effect element (11).
1) and a shunt layer (41) for applying a bias magnetic field to the magnetoresistive effect element (11), a shunt layer (41), both electrodes (21) (twenty one)
A plurality of shunt strips (42) that are parallel to both connection parts are interposed between the connection portion of the magnetoresistive element (11) and the shunt layer (11) due to breakage of the required number of shunt strips (42). A magnetoresistive head having a feature that the diversion ratio of the current flowing in 41) can be adjusted.