JP2000048324A - Magneto-resistive thin-film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistive(MR) thin-film magnetic head which is capable of detecting the signals of different track widths and improving reproduction output by lowering the magnetic reluctance over the entire part of a magnetic circuit. SOLUTION: The MR thin-film magnetic head has the structure obtd. by forming the respective upper magnetic layers 21 of plural magnetic field induction yokes 2A, 2B adjacently arranged in the track width direction to a two- layered structure branched and parallel connected with magnetic paths. Magneto- resistive elements (MR elements or GBR elements) 40A or 40B are disposed at one of the parallel connected layers and MR element 41 for analog signals are arranged on the other. The magnetic paths are branched on the film surface at the upper magnetic layer 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive thin-film magnetic head, and more particularly, to a magnetoresistive element provided in a yoke gap of a magnetic field induction yoke for constructing a closed magnetic path of a signal magnetic field detected by a magnetic gap. The present invention relates to a magnetoresistive thin film magnetic head. More specifically, the present invention provides
The present invention relates to a magnetoresistive thin-film magnetic head capable of reproducing both digital signals and analog signals.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 6-215331 discloses a yoke type composite type thin film magnetic head. This composite thin-film magnetic head is incorporated in a video tape recorder (VTR) or an audio magnetic reproducing device (DCC).

A composite type thin film magnetic head is constructed by a plurality of types of magnetic reproducing heads capable of reproducing signals having different track widths, generally, any of digital signals and analog signals. It is provided on a substrate. The composite thin-film magnetic head includes a lower yoke and an upper yoke that form a closed magnetic path for a signal magnetic field detected by a magnetic gap. The lower yoke and the upper yoke are shared by a plurality of types of magnetic reproducing heads.

[0004] The upper yoke is provided along the direction of the signal magnetic field.
A row gap (two rows of yoke gaps) is provided.
A digital signal magnetoresistive element (MR element) and an analog signal magnetoresistive element (MR element) are arranged in series in the gap between the columns. The lower yoke and the upper yoke are arranged in a plurality of rows in the track width direction. Each of the upper yokes arranged in a plurality of rows is individually provided with a magnetoresistive element for digital signal, and each upper yoke is analog. The signal magnetoresistive effect element is provided to extend over.

[0005] The composite type thin film magnetic head constructed as described above has a structure in which a plurality of types of magnetic reproducing heads can be simultaneously manufactured on the same substrate in a common process, and a feature that a practically sufficient reproducing output can be obtained. is there.

[0006]

However, in the composite type thin film magnetic head disclosed in the above-mentioned publication, no consideration is given to the following points. In other words, since the magnetoresistive effect element having a predominantly large magnetoresistance is inserted in series for the digital signal and the analog signal in the magnetic circuit of the composite thin-film magnetic head, the magnetic resistance of the entire magnetic circuit increases. For this reason, the amount of magnetic flux flowing into each of the digital signal magnetoresistive effect element and the analog signal magnetoresistive effect element cannot be obtained sufficiently, so that the reproduction output of the composite type thin film magnetic head cannot be sufficiently ensured. Further, since the reproduction output cannot be sufficiently secured, the composite type thin film magnetic head cannot cope with high-density recording in which the track width is reduced.

The present invention has been made to solve the above problems. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetoresistive thin film magnetic head capable of detecting signals of different track widths and improving the reproduction output by reducing the magnetic resistance of the entire magnetic circuit.

It is a further object of the present invention to provide a magnetoresistive thin-film magnetic head capable of realizing a smaller device while improving the reproduction output.

A further object of the present invention is to provide a magnetoresistive thin-film magnetic head having a simple structure which can be easily manufactured by reducing the number of magnetic layers and insulator layers while improving the reproduction output. That is.

It is a further object of the present invention to provide a composite magnetoresistive thin film magnetic head on which a digital signal reproducing head and an analog signal reproducing head can be mounted.

[0011]

According to a first aspect of the present invention, a closed magnetic path for a signal magnetic field detected by a magnetic gap is formed in a yoke gap portion. A plurality of magnetic field induction yokes divided in parallel are arranged adjacent to each other in the track width direction, and a magnetoresistive element is disposed in each of the divided yoke gap portions of the magnetic field induction yoke.

In the magnetoresistive thin-film magnetic head thus configured, a plurality of rows of magnetic field induction yokes are arranged in the track width direction, and the magnetic field is recorded on the magnetic recording medium by one or more magnetic field induction yokes. Since information can be reproduced, signals with different track widths can be detected. Furthermore, the magnetic resistance can be reduced by dividing the respective yoke gap portions (arranged portions of the magnetoresistive element) of the magnetic field induction yoke having a large magnetoresistance in the entire magnetic circuit and connecting them in parallel. As a result, the amount of magnetic flux flowing into the magnetoresistance effect element is sufficiently increased, and the reproduction output can be improved. In particular, when the track width is reduced and high-density recording is performed, the magnetic resistance of the entire magnetic circuit increases. However, even in such a case, the amount of magnetic flux flowing into the magnetoresistive element can be sufficiently secured. The reproduction output of the effect type thin film magnetic head can be improved, and high density recording can be dealt with.

A second feature of the present invention is that, in the magnetoresistive thin film magnetic head, a plurality of magnetic field induction yokes arranged adjacently in the track width direction are each divided in parallel in the film thickness direction.

In the magnetoresistive thin-film magnetic head thus configured, in addition to the effect obtained by the first feature of the present invention, the reproduction output is improved in the thickness direction of the magnetic field induction yoke. Since the area occupied by the magnetic field induction yoke can be reduced, the size of the device can be reduced.

A third feature of the present invention is that, in the magnetoresistive thin-film magnetic head, a plurality of magnetic field induction yokes arranged adjacent to each other in the track width direction are divided in parallel on the film surface.

In the magnetoresistive thin-film magnetic head thus configured, in addition to the effect obtained by the first feature of the present invention, the reproduction output is improved on the film surface of the magnetic field induction yoke. Since the number of magnetic layers and the number of insulator layers can be reduced, a magnetoresistive thin-film magnetic head having a simple structure that is easy to manufacture can be realized.

According to a fourth feature of the present invention, in the magnetoresistive thin film magnetic head, one of the yoke gap portions of a plurality of magnetic field induction yokes arranged adjacent to each other in the track width direction is divided into digital signals. The magnetoresistive elements for reproduction are individually arranged, and the magnetoresistive elements for analog signal reproduction are arranged over a plurality of parts of the other yoke gap divided in parallel with the magnetic field induction yoke.

In the magnetoresistive thin-film magnetic head thus configured, a composite type in which a digital signal magnetic reproducing head and an analog signal magnetic reproducing head are incorporated can be realized.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view of the magnetoresistive thin film magnetic head according to the first embodiment of the present invention, and FIG.
It is sectional drawing of the magnetoresistive effect type thin film magnetic head cut | disconnected by F1 cutting line. FIG. 3 is a perspective view of a magnetic field induction yoke of the magnetoresistive thin film magnetic head.

As shown in FIGS. 1 to 3, the magnetoresistive thin-film magnetic head includes a first magnetic field induction yoke 2A and a second magnetic field induction yoke 2A arranged adjacent to the first magnetic field induction yoke 2A in the track width direction. A magnetoresistive element (MR) disposed in the yoke gap 25G of each of the magnetic field induction yoke 2B and the first and second magnetic field induction yokes 2A and 2B.
Element) 40A, 40B and the respective yoke gaps 26 of the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B
A magnetoresistive effect element (MR element) 41 provided in the G portion is constructed. These first magnetic field induction yokes 2
A, second magnetic field induction yoke 2B, magnetoresistive element 40
A, 40B and 41 are provided on the substrate 1. As the substrate 1, for example, a non-magnetic substrate such as an Al ₂ O ₃ —TiC substrate can be practically used.

The first magnetic field induction yoke 2 A basically includes a lower magnetic layer 20 and an upper magnetic layer 21 disposed on the substrate 1. In the present embodiment, the upper magnetic layer 21 has a two-layer structure in the film thickness (vertical) direction,
In the closed magnetic path of the signal magnetic field detected by
The magnetic path is constituted by a parallel connection that branches once before passing through the yoke gap 25G or 26G and is reconnected after passing through the yoke gap 25G or 26G. That is, the upper magnetic layer 21 includes a lower intermediate magnetic layer 21F disposed on the lower magnetic layer 20 via the magnetic gap layer 3 on the magnetic recording medium side (the left side in FIGS. 1 and 3 and the upper side in FIG. 2). The first upper magnetic layer 22F has a first upper magnetic layer 22F disposed on the side opposite to the magnetic recording medium side.
A magnetic path (digital signal detection magnetic path) formed by the upper magnetic layer 22R and the lower intermediate magnetic layer 21R, and an upper intermediate magnetic layer 23F directly disposed on the first upper magnetic layer 22R on the magnetic recording medium side; A second upper magnetic layer 24F, a magnetic path (analog signal detection magnetic path) formed by the second upper magnetic layer 24R and the upper intermediate magnetic layer 23R disposed on the side opposite to the magnetic recording medium side are provided.

A yoke gap 25G is provided between the first upper magnetic layers 22F and 22R, and under the yoke gap 25G, the magnetoresistive element 4 has an insulator 7 interposed therebetween.
0A is provided. The magnetoresistive element 40A is used as a magnetoresistive element for digital signal detection, and is provided only on the first magnetic field induction yoke 2A. As shown in FIG. 2, a sense current for detecting magnetic information recorded on the magnetic recording medium is supplied to one end and the other end of the magnetoresistive element 40A, and the detected detection signal is output. A pair of lead wires 42 to be taken out are electrically connected.

A yoke gap 26G is provided between the second upper magnetic layers 24F and 24R, and a magnetoresistive element 41 is provided below the yoke gap 26G via an insulator 10. The magnetoresistive element 41 is used as a magnetoresistive element for detecting an analog signal, and is disposed across the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B. As shown in FIG. 2, a pair of lead wires 43 is electrically connected to one end and the other end of the magnetoresistive element 41, respectively.

The second magnetic field induction yoke 2B includes a lower magnetic layer 20 and an upper magnetic layer 21 disposed on the substrate 1, similarly to the first magnetic field induction yoke 2A. In the closed magnetic path of the signal magnetic field detected by the magnetic gap layer 3, the magnetic path of the upper magnetic layer 21 is formed by a parallel connection in which the magnetic path is branched once before passing through the yoke gap 25G or 26G and is reconnected after passing through the yoke gap 25G or 26G. That is, the upper magnetic layer 2
1 is a lower intermediate magnetic layer 21 disposed on the lower magnetic layer 20 via the magnetic gap layer 3 on the magnetic recording medium side.
F, first upper magnetic layer 22F, first upper magnetic layer 22R, lower intermediate magnetic layer 2 disposed on the side opposite to the magnetic recording medium side.
A magnetic path (magnetic path for digital signal detection) formed by 1R;
The upper intermediate magnetic layer 23F and the second upper magnetic layer 24 directly disposed on the first upper magnetic layer 22R on the magnetic recording medium side.
F, a magnetic path (analog signal detection magnetic path) formed by the second upper magnetic layer 24R and the upper intermediate magnetic layer 23R disposed on the side opposite to the magnetic recording medium side.

A yoke gap 25G is provided between the first upper magnetic layers 22F and 22R. Below the yoke gap 25G, the magnetoresistive element 4 has an insulator 7 interposed therebetween.
OB is provided. The magnetoresistive element 40B is used as a magnetoresistive element for digital signal detection similarly to the magnetoresistive element 40A of the first magnetic field induction yoke 2A, and is independent of the magnetoresistive element 40A of the first magnetic field induction yoke 2A. Is provided only in the second magnetic field induction yoke 2B. As shown in FIG. 2, a sense current for detecting magnetic information recorded on the magnetic recording medium is supplied to one end and the other end of the magnetoresistive element 40B, and the detected detection signal is output. A pair of lead wires 42 to be taken out are electrically connected.

A yoke gap 26G is provided between the second upper magnetic layers 24F and 24R, and a magnetoresistive element 41 is provided below the yoke gap 26G via the insulator 10. The magneto-resistance effect element 41 is used as a magneto-resistance effect element for detecting an analog signal, and as described above, the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B
It is arranged over and. As shown in FIG. 2, a pair of lead wires 43 is electrically connected to one end and the other end of the magnetoresistive element 41, respectively.

That is, as shown in FIGS. 2 and 3, the signal magnetic field of the digital signal detected by the track width L1 of the first magnetic field induction yoke 2A is equal to the magnetic gap layer 3, the lower intermediate magnetic layer 21F, the first upper magnetic layer. It is detected as a change in resistance of the magnetoresistive element 40A in which the magnetic layers 22F and 22R, the lower intermediate magnetic layer 21R, and the lower magnetic layer 20 are closed magnetic paths. Similarly, the signal magnetic field of the digital signal detected by the track width L1 ′ of the second magnetic field induction yoke 2B is the magnetic gap layer 3, the lower intermediate magnetic layer 21F, the first upper magnetic layer 22F,
It is detected as a resistance change of the magnetoresistive element 40B in which the 2R, the lower intermediate magnetic layer 21R, and the lower magnetic layer 20 are closed magnetic paths.

On the other hand, the signal magnetic field of the analog signal detected at the track width L2 obtained by adding both the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B is equal to the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B. Magnetic gap layer 3, lower intermediate magnetic layer 21F, first upper magnetic layer 22
F, upper intermediate magnetic layer 23F, second upper magnetic layer 24F,
4R, an upper intermediate magnetic layer 23R, a first upper magnetic layer 22R,
It is detected as a resistance change of the two magnetoresistive elements 41 having the lower intermediate magnetic layer 21R and the lower magnetic layer 20 as closed magnetic paths.

An insulator 12 as a protective film is formed on the magnetic field induction yokes 2A and 2B. Al ₂ O for insulator 12
_{One of three} non-magnetic insulating films, SiO ₂ film, is used.

In the magnetoresistive thin-film magnetic head thus configured, a magnet as a constant magnetic flux source is arranged in the direction perpendicular to the magnetic gap layer 3 and the magnetoresistive element 40
The magnetic flux amount φ _SA1 passing through the cross section perpendicular to the magnetic path direction of each of A and 40B and the magnetic flux amount φ _SA2 passing through the cross section perpendicular to the magnetic path direction of the magnetoresistive effect element 41 are both of the upper magnetic layer 21. It can be increased by having a two-layer structure and connecting in parallel. According to the simulation performed by the inventor, the amount of magnetic flux φ _SA1 passing through each of the magnetoresistive elements 40A and 40B, and the amount of magnetic flux φ _SA2 passing through the magnetoresistive element 41
Indicates that the relative magnetic permeability of each of the magnetic layers of the magnetic field induction yokes 2A and 2B and the magnetoresistive elements 40A, 40B and 41 is 10
When set to 00, each increases 9 dB as compared with the series-structured magnetoresistive thin-film magnetic head disclosed in the above-mentioned publication. That is, in the magnetoresistive thin film magnetic head according to the present embodiment, the magnetic resistance of the entire magnetic circuit can be reduced, and the amount of magnetic flux flowing into each of the magnetoresistive elements 40A, 40B, 41 can be increased. Characteristics can be improved.

Next, a method of manufacturing the above-described magnetoresistive thin film magnetic head will be described. 4 to 17 are process cross-sectional views of the magnetoresistive thin-film magnetic head shown in each manufacturing process.

(1) First, as shown in FIG. 4, a lower magnetic layer 20 is formed on the surface of the substrate 1. Al ₂ O _3-
A non-magnetic substrate such as a TiC substrate can be used practically. As the lower magnetic layer 20, a soft magnetic film such as a Ni—Fe film or a CoZrNb amorphous alloy film can be practically used. The magnetic film is formed in a thickness of 1 to 5 μm by a sputtering method or a vapor deposition method, and then patterned. Either ion milling or wet etching is used for patterning.

(2) As shown in FIG. 5, the lower magnetic layer 20
Is buried around the substrate. Al ₂ O ₃ film, S
Any non-magnetic insulating film of the iO ₂ film is used. This nonmagnetic insulating film is formed to have a thickness greater than the thickness of the lower magnetic layer 20, and is then planarized by polishing so as to match the surface of the lower magnetic layer 20.

(3) As shown in FIG. 6, the lower magnetic layer 20
A magnetic gap layer 3 is formed on the surface of the magnetic recording medium (not shown) on the surface. An Al ₂ O ₃ film, S
Any non-magnetic insulating film of an iO ₂ film is used, and this non-magnetic insulating film is patterned after being deposited by a sputtering method.

(4) As shown in FIG. 7, a lower intermediate magnetic layer 21F is formed on the surface of the lower magnetic layer 20 via the magnetic gap layer 3 on the side of the magnetic recording medium and on the side opposite to the magnetic recording medium. , The lower intermediate magnetic layer 21R is formed directly on the surface of the lower magnetic layer 20. Each of the lower intermediate magnetic layers 21F and 21R is formed of the same magnetic material and the same method as the lower magnetic layer 20.

(5) As shown in FIG. 8, an insulator 6 is buried around each of the lower intermediate magnetic layers 21F and 21R. The insulator 6 is made of the same non-magnetic insulating material as the insulator 5 and is formed by the same method.

(6) As shown in FIG. 9, the magnetoresistive elements 40A and 40B used as digital signal detecting magnetoresistive elements are formed on the surface of the insulator 6. Each of the magnetoresistive elements 40A and 40B is, for example, a Ni-Fe film having a thickness of 20 nm, a Ta film having a thickness of 20 nm, and a C film having a thickness of 20 nm.
An oZrMo film (MR film) is formed by sequentially laminating the films by a sputtering method and patterning these films by ion milling. Thereafter, the lead wiring 42 connected to each of the magnetoresistive elements 40A and 40B is formed.
reference). The lead wiring 42 is formed by, for example, forming a Mo film by a sputtering method and patterning the Mo film.

(7) As shown in FIG. 10, an insulator 7 covering each of the magnetoresistive elements 40A and 40B is formed. This insulator 7 is made of a magnetoresistive element 40A or 40B.
And an insulating gap layer that insulates and separates from the first magnetic field induction yoke 2A or 2B. Al ₂ O ₃ film, S
Any non-magnetic insulating film of the iO ₂ film is used. After the non-magnetic insulating film is deposited by a sputtering method, the surface of the non-magnetic insulating film is planarized by polishing.

(8) As shown in FIG. 11, the insulator 7 on each surface of the lower intermediate magnetic layers 21F and 21R is removed, exposing the respective surfaces of the lower intermediate magnetic layers 21F and 21R.

(9) As shown in FIG. 12, the first upper magnetic layer 22F is formed on the surface of the lower intermediate magnetic layer 21F on the magnetic recording medium side, and the lower intermediate magnetic layer 22F is formed on the side opposite to the magnetic recording medium side. A first upper magnetic layer 22R is formed on the surface of 21R. First upper magnetic layers 22F, 22R
Are formed of the same magnetic material and by the same method as the lower magnetic layer 20. The first upper magnetic layers 22F and 22R are separated from each other to form a yoke gap 25G.

(10) As shown in FIG. 13, the insulator 8 is embedded around each of the first upper magnetic layers 22F and 22R. The insulator 8 is made of the same non-magnetic insulating material as the insulator 5 and is formed by the same method.

(11) The upper intermediate magnetic layer 23F is formed on the surface of the first upper magnetic layer 22F on the magnetic recording medium side, and the upper intermediate magnetic layer 23F is formed on the surface of the upper intermediate magnetic layer 22R on the side opposite to the magnetic recording medium side. The magnetic layer 23R is formed (see FIG. 14). Each of the upper intermediate magnetic layers 23F and 23R is formed of the same magnetic material and the same method as the lower magnetic layer 20.

Then, as shown in FIG. 14, an insulator 9 is embedded around each of the upper intermediate magnetic layers 23F and 23R. The insulator 9 is made of the same non-magnetic insulating material as that of the insulator 5 and is formed by the same method.

(12) As shown in FIG. 15, a magnetoresistive element 41 used as a magnetoresistive element for detecting an analog signal is formed on the surface of the insulator 9. The magneto-resistance effect element 41 includes the above-described magneto-resistance effect elements 40A and 40B.
As in each of the above, for example, a Ni-Fe film having a film thickness of 20 nm, a film thickness of 2
A Ta film of 0 nm and a CoZrMo film (MR film) with a thickness of 20 nm are sequentially laminated by sputtering, and these films are patterned by ion milling. Thereafter, the lead wiring 43 connected to the magnetoresistive element 41 is formed (see FIG. 2). The lead wiring 43 is formed, for example, by forming a Mo film by a sputtering method and patterning the Mo film.

(13) As in the steps shown in FIGS. 10 and 11, the insulator 10 covering the magnetoresistance effect element 41 is formed, and a part of the insulator 10 is subsequently removed to remove the upper intermediate magnetic layer 23F, The respective surfaces of the 23R are exposed (see FIG. 16). Then, as shown in FIG. 16, a second recording medium is formed on the surface of the upper intermediate magnetic layer 23F on the magnetic recording medium side.
The upper magnetic layer 24F is formed, and a second magnetic layer is formed on the surface of the upper intermediate magnetic layer 23R on the side opposite to the magnetic recording medium.
The upper magnetic layer 24R is formed. A second upper magnetic layer 24F,
24R are made of the same magnetic material and by the same method as the lower magnetic layer 20. Second upper magnetic layer 24F, 2
4R are separated from each other to form a yoke gap 26G.

(14) As shown in FIG. 17, the insulator 11 is embedded around each of the second upper magnetic layers 24F and 24R. The insulator 11 is formed of the same non-magnetic insulating material as the insulator 5 by the same method.

(15) As shown in FIG. 1, the insulator 12 covering each of the second upper magnetic layers 24F and 24R is formed. Either an Al ₂ O ₃ film or a SiO ₂ non-magnetic insulating film is used for the insulator 12, and this non-magnetic insulating film is deposited by a sputtering method. Although not shown, lead wiring 4
Connection holes (contact holes) are formed in the insulators 12 and the like at the external connection portions 2 and 43, respectively. The connection hole is formed by, for example, ion milling.

When these series of manufacturing steps are completed, the magnetoresistive thin film magnetic head according to the present embodiment is completed.

In the magnetoresistive thin-film magnetic head thus configured, at least two in the track width direction.
First and second magnetic field induction yokes 2A and 2
B, the digital information recorded on the magnetic recording medium can be reproduced by each of the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B.
Since the analog information recorded on the magnetic recording medium can be reproduced by the magnetic field induction yoke 2B, signals with different track widths can be detected. Further, the first magnetic field inducing yoke 2A and the second magnetic field inducing yoke 2A, which have dominantly large magnetic resistance in the entire magnetic circuit.
The magnetic resistance can be reduced by dividing each of the yoke gap portions of B (the portion where the magnetoresistive element is provided) into yoke gaps 25G and 26G and connecting them in parallel. As a result, the amount of magnetic flux flowing into each of the magnetoresistive elements 40A, 40B, 41 is sufficiently increased, and the reproduction output can be improved. In particular, when the track width is reduced and high-density recording is performed, the magnetic resistance of the entire magnetic circuit increases, but even in such a case, the magnetoresistive elements 40A, 40B, and 41 are sufficient.
Therefore, the reproduction output of the magnetoresistive thin-film magnetic head can be improved, and a higher recording density can be realized.

Further, in the magnetoresistive thin-film magnetic head, the reproduction output is improved by the first magnetic field induction yoke 2A,
The first magnetic field induction yoke 2A and the second magnetic field induction yoke 2A are performed in the respective film thickness directions of the second magnetic field induction yoke 2B.
Since the area occupied by B can be reduced, the size of the apparatus can be reduced.

Further, in the magnetoresistive thin-film magnetic head, a composite type in which a magnetic read head for digital signals and a magnetic read head for analog signals are incorporated can be realized.

(Second Embodiment) In this embodiment, in a magnetoresistive thin-film magnetic head, each of the first magnetic field induction yoke and the second magnetic field induction yoke is divided in parallel on the film surface. Will be described. FIG. 19 is a plan view of a magnetoresistive thin-film magnetic head according to a second embodiment of the present invention, and FIG. 18 is a cross-sectional view of the magnetoresistive thin-film magnetic head taken along section line F18-F18 shown in FIG. It is. FIG. 20 is a perspective view of a magnetic field induction yoke of the magnetoresistive thin film magnetic head.

As shown in FIGS. 18 to 20, the magnetoresistive thin-film magnetic head includes a first magnetic field induction yoke 2A,
A second magnetic field induction yoke 2B disposed adjacent to the first magnetic field induction yoke 2A in the track width direction; and a magnetoresistive effect element 40A or 40B disposed in the yoke gap 25G1 of the first magnetic field induction yoke 2A. And a magnetoresistive element 40C disposed in the yoke gap 25G2 of the second magnetic field induction yoke 2B. These first magnetic field induction yoke 2A, second magnetic field induction yoke 2B,
The magnetoresistive elements 40A, 40B and 40C are provided on the substrate 1.

The first magnetic field induction yoke 2A basically includes a lower magnetic layer 20 and an upper magnetic layer 21 disposed on the substrate 1. The upper magnetic layer 21 has a single-layer structure in the present embodiment, and in the closed magnetic path of the signal magnetic field detected by the magnetic gap layer 3, the magnetic path of the upper magnetic layer 21 is branched once before passing through the yoke gaps 25G1 and 25G2. It is configured by a parallel connection that reconnects after passing through the yoke gaps 25G1 and 25G2. That is, the upper magnetic layer 21 is an intermediate magnetic layer 21F disposed on the lower magnetic layer 20 via the magnetic gap layer 3 on the magnetic recording medium side (the left side in FIGS. 18 and 20 and the upper side in FIG. 19). Magnetic layer 22F, upper dual-purpose magnetic layer 2 disposed on the side opposite to the magnetic recording medium side
A magnetic path formed by the 2R and the intermediate magnetic layer 21R is provided, and each of the upper dual-purpose magnetic layers 22F and 22R is branched on the film surface to form a magnetic path connected in parallel.

A yoke gap 25G1 is provided between one branched upper magnetic layer 22F and one branched upper magnetic layer 22R.
Under the 5G1 portion, the magnetoresistive effect element 4
0A is provided. The magnetoresistive element 40A is used as a magnetoresistive element for digital signal detection, and is provided only on the first magnetic field induction yoke 2A. As shown in FIG. 19, a sense current for detecting magnetic information recorded on the magnetic recording medium is supplied to one end and the other end of the magnetoresistive element 40A, and the detected detection signal is output. A pair of lead wires 42 to be taken out are electrically connected.

A yoke gap 25G2 is provided between the other branched one of the upper dual-purpose magnetic layer 22F and the other branched one of the upper dual-purpose magnetic layer 22R, and an insulating material is provided below the yoke gap 25G2. A magnetoresistive element 40C is provided via body 7. Magnetoresistive element 40C
Are used as a magnetoresistive effect element for detecting an analog signal, and include a first magnetic field induction yoke 2A and a second magnetic field induction yoke 2B.
It is arranged over and. As shown in FIG. 19, a pair of lead wires 43 is electrically connected to one end and the other end of the magnetoresistive element 40C.

The second magnetic field induction yoke 2B includes a lower magnetic layer 20 and an upper magnetic layer 21 disposed on the substrate 1, similarly to the first magnetic field induction yoke 2A. In the closed magnetic path of the signal magnetic field detected by the magnetic gap layer 3, the magnetic path of the upper magnetic layer 21 is configured to be branched once before passing through the yoke gaps 25G1 and 25G2 and to be connected again after passing through the yoke gaps 25G1 and 25G2. That is, the upper magnetic layer 21 is provided on the lower magnetic layer 20 on the magnetic recording medium side with the intermediate magnetic layer 21 disposed via the magnetic gap layer 3.
F, upper dual-purpose magnetic layer 22F, upper dual-purpose magnetic layer 22R and intermediate magnetic layer 21 disposed on the side opposite to the magnetic recording medium side
R and a magnetic path formed of the upper magnetic layer 22F,
Each of the 2Rs is branched on the film surface to form a magnetic path connected in parallel.

A yoke gap 25G1 is provided between one branch of the upper dual-purpose magnetic layer 22F and one branch of the upper dual-purpose magnetic layer 22R.
Under the 5G1 portion, the magnetoresistive effect element 4
OB is provided. The magnetoresistive element 40B is used as a magnetoresistive element for digital signal detection, and is provided only on the second magnetic field induction yoke 2B independently of the magnetoresistive element 40A of the first magnetic field induction yoke 2A. FIG.
As shown in (1), a pair of lead wires 42 is electrically connected to one end and the other end of the magnetoresistive element 40A.

A yoke gap 25G2 is provided between the other branched one of the upper dual-purpose magnetic layer 22F and the other branched one of the upper dual-purpose magnetic layer 22R. An insulating material is provided below the yoke gap 25G2. A magnetoresistive element 40C is provided via body 7. Magnetoresistive element 40C
Are used as a magnetoresistive effect element for detecting an analog signal, and include a first magnetic field induction yoke 2A and a second magnetic field induction yoke 2B.
It is arranged over and. As shown in FIG. 19, a pair of lead wires 43 is electrically connected to one end and the other end of the magnetoresistive element 40C.

The first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B are each formed in a line symmetrical shape.

As shown in FIGS. 19 and 20, the signal magnetic field of the digital signal detected at the track width L1 of the first magnetic field induction yoke 2A is equal to the magnetic gap layer 3 and the intermediate magnetic layer 21.
F, upper dual-purpose magnetic layers 22F, 22R, intermediate magnetic layer 21R
And the lower magnetic layer 20 as a closed magnetic path is detected as a change in resistance of the magnetoresistive element 40A. Similarly, the signal magnetic field of the digital signal detected at the track width L1 'of the second magnetic field induction yoke 2B is equal to the magnetic gap layer 3, the intermediate magnetic layer 2
1F, upper dual-purpose magnetic layers 22F, 22R, intermediate magnetic layer 21
It is detected as a change in resistance of the magnetoresistive element 40B in which the R and the lower magnetic layer 20 are closed magnetic paths.

On the other hand, the signal magnetic field of the analog signal detected with the track width L2 obtained by adding both the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B is equal to the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B. , The magnetic gap layer 3, the intermediate magnetic layer 21F, the upper dual-purpose magnetic layer 22F,
It is detected as a change in resistance of two magnetoresistive elements 40C having the 2R, intermediate magnetic layer 21R and lower magnetic layer 20 as closed magnetic paths.

An insulator 12 as a protective film is formed on the magnetic field induction yokes 2A and 2B.

In the magnetoresistive thin film magnetic head thus configured, a magnet as a constant magnetic flux source is arranged in the direction perpendicular to the magnetic gap layer 3 and the magnetoresistive element 40
The magnetic flux amount φ _SA1 passing through the cross section perpendicular to the direction of the magnetic path of each of A and 40B and the magnetic flux amount φ _SA2 passing through the cross section perpendicular to the direction of the magnetic path of the magnetoresistive effect element 40C both pass through the upper magnetic layer 21. It can be increased by having a single layer structure and connecting in parallel. According to the simulation performed by the inventor, when the relative magnetic permeability of each magnetic layer of the magnetic field induction yokes 2A and 2B and each of the magnetoresistive elements 40A, 40B and 40C are set to 1000, the above-mentioned publication discloses the above. Compared to the series structure magnetoresistive thin film magnetic head, the magnetoresistive element 4
The amount of magnetic flux φ _SA1 passing through each of 0A and 40B is 3.2d
B, the amount of magnetic flux φ _SA2 passing through the magnetoresistive element 40C is 3.
Both increase to 7dB. That is, in the magnetoresistive thin-film magnetic head according to the present embodiment, the magnetoresistance of the entire magnetic circuit can be reduced, and the magnetoresistive elements 40A, 40B,
Since the amount of magnetic flux flowing into each of the 40C can be increased,
The reproduction output characteristics can be improved.

Next, a method of manufacturing the above-described magnetoresistive thin film magnetic head will be described. 21 to 29 are process sectional views of the magnetoresistive thin-film magnetic head shown in each manufacturing process.

(1) First, as shown in FIG.
The lower magnetic layer 20 is formed on the surface of the substrate. Substrate 1 has Al ₂ O
A non-magnetic substrate such as a _3- TiC substrate can be used practically. As the lower magnetic layer 20, a soft magnetic film such as a Ni—Fe film or a CoZrNb amorphous alloy film can be practically used. The magnetic film is formed in a thickness of 1 to 5 μm by a sputtering method or a vapor deposition method, and then patterned. Ion milling for patterning,
Either wet etching is used.

(2) As shown in FIG. 22, the lower magnetic layer 2
The insulator 5 is buried around 0. Al ₂ O ₃ , S
Any non-magnetic insulating film of iO ₂ is used. This nonmagnetic insulating film is formed to have a thickness greater than the thickness of the lower magnetic layer 20, and is then planarized by polishing so as to match the surface of the lower magnetic layer 20.

(3) As shown in FIG. 23, the lower magnetic layer 2
The magnetic gap layer 3 is formed on the surface of the magnetic recording medium (not shown) on the surface of the magnetic recording medium. Al ₂ O for the magnetic gap layer 3
_{One of three} non-magnetic insulating films, SiO ₂ film, is used. This non-magnetic insulating film is patterned after being deposited by a sputtering method.

(4) As shown in FIG. 24, the magnetic gap layer 3 is formed on the surface of the lower magnetic layer 20 on the magnetic recording medium side.
, And the intermediate magnetic layer 21R is formed directly on the surface of the lower magnetic layer 20 on the side opposite to the magnetic recording medium side. Intermediate magnetic layer 21F, 2
1R is formed of the same magnetic material and the same method as the lower magnetic layer 20.

(5) As shown in FIG. 25, the intermediate magnetic layer 2
An insulator 6 is buried around each of 1F and 21R.
The insulator 6 is made of the same non-magnetic insulating material as the insulator 5 and is formed by the same method.

(6) As shown in FIG. 26, on the surface of the insulator 6, the magnetoresistive elements 40A and 40B used as digital signal detecting magnetoresistive elements and the analog signal magnetoresistive elements are used. The respective magnetoresistive effect elements 40C are formed in the same manufacturing process. Each of the magnetoresistive elements 40A, 40B, and 40C is, for example, a 20-nm-thick Ni—Fe film, a 20-nm-thick Ta film, and a 20-nm-thick CoZrMo film.
Films (MR films) are sequentially laminated by a sputtering method, and these films are formed by patterning by ion milling. Thereafter, the lead wiring 42 connected to each of the magnetoresistive elements 40A and 40B,
The lead wiring 43 connected to C is formed (see FIG. 19). Each of the lead wires 42 and 43 is formed by, for example, forming a Mo film by a sputtering method and patterning the Mo film.

(7) As shown in FIG. 27, the insulator 7 covering each of the magnetoresistive elements 40A, 40B, 40C
To form This insulator 7 includes a magnetoresistive element 40A,
An insulating gap layer that insulates and separates each of the first magnetic field induction yokes 2A and 2B from each of the first and second magnetic field induction yokes 40B and 40C is formed. Either an Al ₂ O ₃ film or a SiO ₂ non-magnetic insulating film is used for the insulator 7. The non-magnetic insulating film is deposited by sputtering, and then the surface of the non-magnetic insulating film is planarized by polishing. Is done.

(8) As shown in FIG. 28, the intermediate magnetic layer 2
The insulator 7 on each surface of 1F, 21R is removed, exposing each surface of the intermediate magnetic layers 21F, 21R.

(9) As shown in FIG. 29, the upper dual-purpose magnetic layer 22F is formed on the surface of the intermediate magnetic layer 21F on the magnetic recording medium side, and the surface of the intermediate magnetic layer 21R is formed on the opposite side to the magnetic recording medium side. Upper combined magnetic layer 22 on top
Form R. Each of the upper dual-purpose magnetic layers 22F and 22R is made of the same magnetic material and the same method as the lower magnetic layer 20. The yoke gaps 25G1 and 25G2 are formed between the upper dual-purpose magnetic layers 22F and 22R.

(10) The insulator 8 is buried around each of the upper dual-purpose magnetic layers 22F and 22R, and the insulator 12 covering each of the upper dual-purpose magnetic layers 22F and 22R is formed as shown in FIG. . Al ₂ O ₃ film, SiO _{2
One of the two} non-magnetic insulating films is used, and this non-magnetic insulating film is deposited by a sputtering method. Although not shown,
In each of the external connection portions of the lead wires 42 and 43, a connection hole is formed in the insulator 12 or the like. The connection hole is formed by, for example, ion milling.

When these series of manufacturing steps are completed, the magnetoresistive thin film magnetic head according to the present embodiment is completed.

In the magnetoresistive thin-film magnetic head thus configured, in addition to the effects obtained by the magnetoresistive thin-film magnetic head according to the above-described first embodiment, the improvement of the reproduction output is also important. This operation is performed on the respective film surfaces of the first magnetic field induction yoke 2A and the second magnetic field induction yoke 2B, and the number of magnetic layers and the number of insulator layers can be reduced. A head can be realized.

The present invention is not limited to the above embodiment. For example, the present invention provides a magnetoresistive element 40A,
A GMR element can be used for each of 40B, 40C and 41. Further, the present invention provides the first magnetic field induction yoke 2A,
A yoke gap may be provided in each lower magnetic layer 20 of the magnetic field induction yoke 2B, and a magnetoresistive element may be provided in the yoke gap. Further, the present invention can be applied to a magnetoresistive thin film magnetic head having three or more magnetic field inducing yokes arranged in the track width direction.

[0079]

According to the present invention, it is possible to provide a magnetoresistive thin film magnetic head capable of detecting signals of different track widths and improving the reproduction output by reducing the magnetic resistance of the entire magnetic circuit.

Further, according to the present invention, it is possible to provide a magnetoresistive thin film magnetic head capable of realizing the miniaturization of the device while improving the reproduction output.

Further, the present invention can provide a magnetoresistive thin film magnetic head having a simple structure which can be easily manufactured by reducing the number of magnetic layers and insulator layers while improving the reproduction output.

Further, the present invention can provide a composite magnetoresistive thin film magnetic head on which a digital signal reproducing head and an analog signal reproducing head can be mounted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetoresistive thin-film magnetic head according to a first embodiment of the present invention.

FIG. 2 is a plan view of the magnetoresistive thin-film magnetic head according to the first embodiment.

FIG. 3 is a perspective view of a magnetic field induction yoke of the magnetoresistive thin film magnetic head according to the first embodiment.

FIG. 4 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 5 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 6 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 7 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 8 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment.

FIG. 9 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment.

FIG. 10 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 11 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 12 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 13 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment.

FIG. 14 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 15 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 16 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 17 is a process sectional view of the magnetoresistive thin-film magnetic head according to the first embodiment;

FIG. 18 is a sectional view of a magnetoresistive thin film magnetic head according to a second embodiment of the present invention.

FIG. 19 is a plan view of a magnetoresistive thin-film magnetic head according to a second embodiment.

FIG. 20 is a perspective view of a magnetic field induction yoke of the magnetoresistive thin film magnetic head according to the second embodiment.

FIG. 21 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment.

FIG. 22 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment.

FIG. 23 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment;

FIG. 24 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment;

FIG. 25 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment.

FIG. 26 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment;

FIG. 27 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment;

FIG. 28 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment.

FIG. 29 is a process sectional view of the magnetoresistive thin-film magnetic head according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2A, 2B Magnetic field induction yoke 20 Lower magnetic layer 21 Upper magnetic layer 21F, 21R Lower intermediate magnetic layer or intermediate magnetic layer 22F, 22R 1st upper magnetic layer or upper combined magnetic layer 23F, 23R Upper intermediate magnetic layer 24F, 24R Second upper magnetic layer 25G, 25G1, 25G2, 26G Yoke gap 3 Insulating gap layer 40A, 40B, 40C, 41 Magnetoresistance element 5-12 Insulator

Claims (4)

[Claims] 1. A magnetic field induction yoke in which a closed magnetic path of a signal magnetic field detected by a magnetic gap is divided in parallel at a yoke gap portion, a plurality of magnetic field induction yokes are arranged adjacently in a track width direction, and the magnetic field induction yokes are divided in parallel. A magnetoresistive thin-film magnetic head, wherein a magnetoresistive element is disposed in each yoke gap. 2. The magnetoresistive thin-film magnetic head according to claim 1, wherein each of the plurality of magnetic field inducing yokes arranged adjacent to each other in the track width direction is divided in parallel in the film thickness direction. 3. The magnetoresistive thin-film magnetic head according to claim 1, wherein each of the plurality of magnetic field inducing yokes arranged adjacent to each other in the track width direction is divided in parallel on the film surface. 4. A magnetoresistive element for reproducing digital signals is individually disposed in one of the parallel yoke gap portions of a plurality of magnetic field induction yokes arranged adjacent to each other in the track width direction. 4. The analog signal reproducing magnetoresistive element is disposed over a plurality of other yoke gap portions of the induction yoke that are divided in parallel. A magnetoresistive thin-film magnetic head.