JPH0689410A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the durability to sliding with a recording medium surface by forming the end faces of laminated magnetic films constituting a part of yoke parts as magnetic gap surfaces and functioning the film thickness of the laminated magnetic films as a track width. CONSTITUTION:The second magnetic gap 9 of the magnetic head is provided on the side opposite to the first magnetic gap 8 and an MR element 11 is disposed across this second magnetic gap 9, i.e., in the form of bridging the laminated bodies (yokes) 6, 6'. The structure formed by using the end faces of the laminates of the magnetic thin films-nonmagnetic insulating films forming the so-called yoke parts and cores as the magnetic gap surfaces and using the film thickness of the laminates as the track width is easily adoptable and, therefore, the setting of the large gap depth is possible and the wear by sliding with the tape recording medium is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head, and more particularly to a magnetic head.
The present invention relates to a magnetoresistive effect type magnetic head suitable for VTR reproduction and the like.

[0002]

2. Description of the Related Art In recent years, with the increasing density of magnetic recording, VTR
In 500Mb / inch ^2, the system of high recording density of 200 Mb / inch ² in HDD are commercialized. In these systems, an induction type magnetic head is mainly used, but much attention is paid to a magnetoresistive effect type magnetic head having a high S / N property. In other words, a magnetic head (MR head) that utilizes the magnetoresistive effect that the electric resistance of a certain kind of magnetic thin film or magnetic multilayer thin film is changed by an external magnetic field can be used even in a system where the relative speed between the magnetic head and the recording medium is slow. High output can be obtained. For this reason, it has been mainly used in a system for reproducing a fixed head type tape-shaped recording medium, but recently, a relative speed of several meters / sec, which is about the same as that of a consumer VTR, is relatively high. Even in small HDDs, magneto-resistive magnetic heads are used instead of inductive magnetic heads. At present, the magnetoresistive effect type magnetic head is not in practical use in the rotary head type VTR, but
The S / N property has attracted attention as a reproducing magnetic head.

By the way, as shown in FIG. 17, a constant current of direct current or alternating current called a sense current is passed through the lead portions 1a and 1b to the element 1 having the magnetoresistive effect included in the magnetoresistive type magnetic head. Therefore, when the target is a tape-shaped recording medium, the sense current may leak to the recording medium side. Therefore, in a practical yoke type magnetic head, the element (MR element) 1 exhibiting the magnetoresistive effect is prevented from being exposed on the sliding surface of the tape-shaped recording medium as shown in a perspective view of the main part in FIG. In this configuration, the flux guides (yoke portions) 3 and 3'that form a core magnetic path integrally supported on the surface of the insulating substrate 2 are arranged and mounted via an insulating film. The upper yoke portion 3 is covered with a ceramic insulating substrate or insulating layer for surface protection.

[0004]

However, in the yoke type magnetic head having the above structure, the yoke portions 3, 3'are provided.
Is formed by plating or etching the magnetic thin film formed on the surface of the insulating substrate 2, the thickness 3a of the yoke portions 3 and 3'is only about several .mu.m at the most. Generally, in order to prevent the reproduction efficiency of the thin film head from decreasing, the yoke portion 3,
The thickness 3a of 3'needs to be about the same as the depth 4 of the gap for taking in the magnetic field from the recording medium. Therefore, in the case of the configuration shown in FIG. 18, the gap depth 4 is set to several μm.
Unless it is reduced to about m, the regeneration efficiency will decrease. However, in the case of VTR, as is well known, the wear of the magnetic head can be severe, so it is necessary to set the gap depth 4 in the initial stage to at least about 15 μm. To cope with such a problem, if the thickness 3a of the yoke portions 3 and 3'is set to 15 μm or more, not only is there a lot of difficulty in the manufacturing process, but even if it is possible to realize it, the yoke portion will not be realized. Due to the eddy current loss of 3 and 3 ', the magnetic permeability in the high frequency region becomes very low, and the reproduction efficiency is lowered. Further, if the yoke portions 3 and 3'are formed of a multi-layer magnetic film in order to prevent the eddy current loss, there is a problem that the insulating film between the magnetic films acts as a magnetic gap, and a pseudo signal overlaps the reproduced waveform. is there. In other words, the conventional yoke type magnetic head having the above configuration is
It was practically impossible to use for the reproduction of TR.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a yoke type MR magnetic head having durability and capable of reproducing a VTR with high efficiency.

[0006]

A magnetic head according to the present invention has a structure in which a laminated body of a soft magnetic thin film and an insulating thin film is sandwiched by non-magnetic materials, and is a first magnetic field for taking in a magnetic field from a magnetic recording medium. A magnetic head main body which has a magnetic gap and forms a substantially ring-shaped core magnetic path, and a portion of a region of the magnetic head main body which is not in contact with the magnetic recording medium is provided with a gap larger than the first magnetic gap. It is characterized by comprising a second magnetic gap and a thin film element having a magnetoresistive effect integrally arranged in the vicinity of the second magnetic gap.

According to the present invention, the thickness of the yoke portion (core), in other words, the thickness of the laminated body of soft magnetic thin film-insulating thin film (laminated magnetic film) is set to a relatively large thickness of about 0.1 to 1 mm, and the depth of the gap is set. In order to cope with the wear of the head surface due to sliding with the recording medium, a second magnetic gap is provided in a region that does not slide with respect to the recording medium, and an MR element is arranged in the vicinity of this. This is a yoke-type magnetic head whose main point is what is done. Here, it is preferable to match the thickness of the laminated body of the soft magnetic thin film-insulating thin film (laminated magnetic film) with the so-called track width, and it is not necessary to make the thickness of the laminated magnetic film uniform throughout. Alternatively, only the region close to the first magnetic gap for taking in the magnetic field from the recording medium may be combined with the track width.

[0008]

In the magnetic head according to the present invention, the end surface of the laminated magnetic film forming a part of the yoke portion is used as the magnetic gap surface,
Further, by making the film thickness of the laminated magnetic film function as the track width, it is possible to increase the depth of the gap for taking in the magnetic field from the recording medium, which also provides durability against sliding on the recording medium surface. To be done. Moreover, since the laminated magnetic film has a configuration in which soft magnetic thin films and insulating thin films are alternately laminated, eddy current loss is also reduced,
Furthermore, the high frequency characteristics are good, and in combination with the good S / N property, the VTR
It can be said that it greatly contributes to the increase of the regeneration efficiency of the.

[0009]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 and FIG. 2 are perspective views showing an example of a main part configuration of a yoke type magnetic head according to the present invention from different directions. In FIGS. 1 and 2, reference numerals 5 and 5'denominate a laminated body (laminated magnetic film ... Yoke) 6 and 6'of a soft magnetic thin film and an insulating thin film, respectively.
It is a member that is sandwiched by a ', 7b, and 7b'. The two members 5 and 5'are formed of the laminated body (yoke) 6,
6'forms a core magnetic path having a first magnetic gap 8 for taking in a magnetic field from a magnetic recording medium (not shown) and a second magnetic gap 9 described later, that is, a substantially ring-shaped core magnetic path. While constituting the magnetic head body 10. Further, the second magnetic gap 9 is formed in a part of a region of the magnetic head body 10 which is not in contact with the magnetic recording medium,
A thin film element (MR element) 11 having a magnetoresistive effect is provided in the vicinity of the second magnetic gap 9 with a gap larger than that of the first magnetic gap 8. They are integrally arranged (electrically insulated from the parts 6 and 6 '). FIG. 3 is an enlarged schematic view showing a state in which the MR element 11 is integrally arranged via the insulating film 12 (electrically insulated from the yoke portions 6 and 6 '). Reference numeral 11 has a structure shielded by a magnetic shield film 14 via an insulating film 12a.

In the above configuration example, the second magnetic gap 9 is provided on the opposite side of the first magnetic gap 8, and the MR element is also provided.
The reference numeral 11 is arranged so as to straddle the second magnetic gap 9, in other words, to bridge the laminated bodies (yokes) 6 and 6 '. In addition, in FIGS. 1 and 2, 11a and 11b are
The output detecting lead of the MR element 11 and 13 are gaps where the members 5 and 5'form a substantially ring-shaped core magnetic path.

The MR element 11 is generally made of a ferromagnetic material such as NiFe, and utilizes a resistance portion that changes with cos ² θ depending on the angle θ formed by the direction of current and the direction of magnetization. However, recently, in the magnetic two-layer film,
Depending on the angle φ formed by the magnetization directions of the two layers, a spin valve phenomenon in which the electric resistance changes with cosφ or in a magnetic multilayer film, the electric resistance depends on the angle formed by the magnetizations of adjacent layers. Examples thereof include those utilizing a phenomenon that greatly changes, and the present invention may be based on any phenomenon including the phenomena exemplified above.

Next, the operation principle of the yoke type magnetic head having the above structure will be described.

When the magnetic head comes into contact with the surface of the recording medium running along R of the magnetic head, the magnetic flux generated from the recording medium is taken in through the first magnetic gap 8 and enters from the yoke (core) 6. It passes through the insulating film 12 on the side of the second magnetic gap 9, passes through the MR element 11, passes through the insulating film 12 again, passes through the yoke (core) 7, and returns to the recording medium. At this time, since the magnetic flux passing from the yoke (core) 6 to the yoke (core) 7 without passing through the MR element 11 does not contribute to the reproduction output, the ratio of the magnetic flux short-circuited here is reduced as much as possible. The distance (gap) 13 between the yoke (core) 6 and the yoke (core) 7 is set to be large for the first magnetic gap 8 and the second magnetic gap 9.

4 and 5 are perspective views showing another different embodiment of the present invention. First, in the case of the structure shown in FIG. 4, the magnetic head body 10 sandwiches the laminated body (yoke) 6, 6'of the soft magnetic thin film and the insulating thin film by the non-magnetic bodies 7a, 7a ', 7b, 7b', respectively. Members 5 that make up the structure
In addition to 5 ′, insulating soft magnetic films 15a and 15b such as NiZn ferrite are provided on the non-magnetic insulators 16a and 16a, respectively.
Members 5a, 5 which are configured to be sandwiched by 16a ', 16b, 16b'
It consists of a '. Then, these members 5,
Reference numerals 5 ', 5a, 5a' denote a first magnetic gap 8 for taking in a magnetic field from a magnetic recording medium (not shown), and a first magnetic gap 8 by the laminated bodies (yokes) 6, 6'and the soft magnetic films 15a, 15b. The magnetic head main body 10 is formed while forming the second magnetic gap 9 and forming a core magnetic path having a substantially ring shape. The second magnetic gap 9
Is provided with a gap larger than the first magnetic gap 8 in a part of a region of the magnetic head body 10 which is not in contact with the magnetic recording medium, and a magnetic resistance is provided in the vicinity of the second magnetic gap 9. A thin film element (MR element) 11 having an effect is integrally arranged, and in this configuration, unlike the case of FIGS. 1 and 2, the insulating film 12 does not need to be interposed.

On the other hand, in the case of the structure shown in FIG. 5, the second magnetic gap 9 is arranged on the opposite side of the first magnetic gap 8 in the case shown in FIGS. The second magnetic gap 9 is provided on the side surface side, and the MR element 11 is arranged so as to straddle the second magnetic gap 9, and the yoke portion (core) is formed.
6, 6'and the magnetic path are formed. In this configuration, the MR element 11 and its leads 11a,
11b is arranged on an insulating layer (not shown) on the surfaces of the yoke portions (cores) 6 and 6 '.

When the magnetic head of the present invention having such a structure is used for reproducing a VTR, as in the case of the induction type magnetic head, as shown in FIGS. 6 (a) and 6 (b), the so-called base plate is used. Attach to 17 and use. Here, FIGS. 6 (a) and 6 (b)
Shows the front and back structures, 18a and 18b are lead terminals for taking out signals through the cylinder, and 18c is a lead wire for connecting the magnetic head and the lead terminals 18a and 18b.

Next, FIGS. 7 to 15 showing a perspective view of the embodiment.
An example of a method for manufacturing the yoke-type magnetic head having the above-described structure will be described with reference to FIG.

First, a non-magnetic substrate 7 is prepared, and a magnetic thin film 15 such as sendust is deposited on the surface of the non-magnetic substrate 7 by evaporation or sputtering to a thickness of about 1 to 4 μm. After that, a non-magnetic insulating film 16 such as SiO ₂ having a thickness of 0.2 to 0.5 m is formed on the magnetic thin film 15 in the same manner.
Then, a magnetic thin film 15 such as sendust is deposited to a thickness of 1 to 4 μm. Here, the lamination of the magnetic thin film 15 and the non-magnetic insulating film 16 is repeated so as to have a thickness corresponding to the required track width. In this way, the magnetic thin film 15-nonmagnetic insulating film 16 having a required thickness is formed.
After the glass layer 19 for bonding is deposited / formed on the laminated body (film) of, for example, by sputtering (FIG. 7), a plurality of non-magnetic substrates 7 provided with these laminated films are superposed.
The bonding block 20 is formed by the fusion action of the glass layer 19 (FIG. 8). Next, the joining block 20 is cut and separated along the broken line to form a block piece 21 as shown in FIG. In cutting / separating into the block pieces 21, the angle θ with respect to the cutting / separating surface of the laminated body (film) of the magnetic thin film 15-nonmagnetic insulating film 16 is selected so as to match the azimuth angle.
Set. Then, the block pieces 212 are individually selected as a pair, and as shown in FIG. 10, after forming the winding groove 21a and the magnetic gap 21b on one block piece 21, the winding groove 21a and the magnetic gap 21b are formed. The surface of the other block piece 21 facing the surface is polished to a predetermined surface accuracy. As mentioned above, on the block piece 21 that has undergone the required polishing process,
After the non-magnetic films for the gap spacers have been formed by adhesion, as shown in FIG. 11, they are laminated and integrated by a fusion action of glass or the like. Here, the winding groove 21a and the magnetic gap 21b are exemplified as two rows,
By cutting and separating along the dotted line 22, a block having a configuration in which one row such as the winding groove and the magnetic gap 21b is formed can be obtained.

In this way, a plurality of blocks each having the winding groove 21a and the magnetic gap 21b formed in one row are rearranged with the rear magnetic gap side as the upper surface so that the core positions of the blocks are aligned. Then, each block is bonded and integrated with a low melting point glass to form a wafer (Fig.
13). Then, as shown in FIG. 14, the wafer surface integrally bonded is mirror-polished, and a thin insulating film 12 is formed on the upper surface of the rear magnetic gap formation side by a method such as sputtering or vapor deposition. After forming a NiFe film or a multilayer film having a magnetoresistive effect on the insulating film 12 by straddling each magnetic thin film 15-nonmagnetic insulating film 16 laminated body region by a method such as sputtering or vapor deposition, a lithographic technique The MR element 11 is integrally arranged by forming the magnetic sensing section (MR element) 11 and the lead wires 11a and 11b. Here, if necessary, a shield film or a protective film is formed on the MR element 11 formation surface.
Next, after cutting and separating the wafer along the line 23a, the surface opposite to the MR element 11 forming surface is cylindrically ground so as to make a good contact with the tape-like recording surface. 15
After the block as shown in FIG. 1 is created and then sliced along the line 23b, the yoke type magnetic head as shown in FIG. 1 is obtained.

Further, FIG. 16 is a perspective view showing another embodiment of the present invention. The basic structure is similar to that of the above example, but in this example, the magnetic films stacked to have a thickness larger than the track width are used as the yokes 6 and 6'and the first magnetic gap 8 is formed.
The thickness of the portion of the magnetic film is used as the track width. When the track width becomes narrow, it is necessary to prevent the efficiency from decreasing by reducing the magnetic resistance of the yokes 6 and 6'as much as possible. A configuration in which the number of laminated layers is increased is desirable.

[0022]

As described above, in the yoke type MR magnetic head according to the present invention, the end face of the magnetic thin film-nonmagnetic insulating film forming the so-called yoke portion or core is used as the magnetic gap surface, and the magnetic layer is laminated. Since the structure in which the body width is the track width can be easily adopted, the conventional bulk dielectric type is used.
0.1 to 1 mm, which is the pole length of the VTR head (thickness of the core or yoke surface that contacts the running tape-shaped recording medium)
Since the gap depth can be set to a large value, the functional deterioration (deterioration) due to abrasion due to sliding on the tape recording medium surface is prolonged (durability). Sexualize).

[Brief description of drawings]

FIG. 1 is a perspective view showing a structural example of a magnetic head according to the present invention from the surface side on which an MR element is arranged.

FIG. 2 is a perspective view showing a configuration example of a magnetic head according to the present invention from the first magnetic gap formation surface side.

FIG. 3 is an enlarged perspective view showing an arrangement state of MR elements in a configuration example of a magnetic head according to the present invention.

FIG. 4 is a perspective view showing another configuration example of the magnetic head according to the present invention from the surface side on which the MR element is arranged.

FIG. 5 is a further example of the configuration of the magnetic head according to the present invention.
The perspective view shown from the surface side which has arrange | positioned MR element.

6A and 6B show an example of mounting a magnetic head according to the present invention, in which FIG. 6A is a top perspective view and FIG. 6B is a bottom perspective view.

FIG. 7 is a perspective view showing a material in which a laminated magnetic film or the like is formed on the surface of a non-magnetic substrate (body) in a manufacturing embodiment example of a magnetic head according to the present invention.

8 is a perspective view showing a joining block in which the materials shown in FIG. 7 are laminated and integrated in an example of a manufacturing embodiment of a magnetic head according to the present invention.

9 is a perspective view showing a block piece obtained by cutting and separating the joining block shown in FIG. 8 in a manufacturing embodiment example of a magnetic head according to the present invention.

FIG. 10 is a perspective view showing a state in which a winding groove and a gap groove are provided on one main surface of a block piece in a manufacturing embodiment example of a magnetic head according to the present invention.

FIG. 11 is a perspective view showing a block in which the joining block piece shown in FIG. 10 is joined as one of the pair pieces in the manufacturing embodiment example of the magnetic head according to the invention.

FIG. 12 is a perspective view showing a state in which the joined blocks are cut and separated in the magnetic head manufacturing embodiment according to the present invention.

FIG. 13 is a perspective view showing a wafer in which the blocks shown in FIG. 12 are laminated and arranged in a fixed direction and bonded and integrated in the embodiment of the magnetic head manufacturing embodiment according to the invention.

FIG. 14 is an enlarged perspective view showing a state in which MR elements are arranged on a predetermined surface of a wafer in a manufacturing embodiment example of a magnetic head according to the present invention.

FIG. 15 is a perspective view showing a state in which a wafer, on which a MR element is arranged on a predetermined surface, is cut and separated in the magnetic head manufacturing embodiment according to the present invention.

FIG. 16 is a perspective view showing still another configuration example of the magnetic head according to the present invention.

FIG. 17 is a perspective view showing the basic configuration of an MR element.

FIG. 18 is a perspective view showing a configuration of a main part of a conventional yoke type MR magnetic head.

[Explanation of symbols]

1, 11 ... MR element 1a, 1b, 11a, 11b ... Lead section
2 ... Insulating substrate 3, 3 '... Flux guide (yoke portion) 3a ... Yoke portion thickness 4 ... Magnetic gap depth 5, 5', 5a, 5a '... Member 6,6' ... Magnetic laminate (yoke) Part) 7, 7a, 7a ', 7b, 7b' ... non-magnetic material 8 ... first magnetic gap 9 ... second magnetic gap 10 ... magnetic head body 12, 12a ... insulating film 13
… Gap 14… Magnetic shield 15, 15a, 15b…
Insulating soft magnetic film 16, 16a, 16b ... Non-magnetic insulator
17 ... Base plate 18a, 18b ... Lead terminal 18c ... Lead wire 19 ... Bonding glass layer 20 ... Bonding block
21 ... Block piece 21a ... Winding groove 21b ... Magnetic gap 22 ... Dotted line 23a, 23b ... Cutting line

Claims (1)

[Claims] 1. A substantially ring-shaped core magnet having a structure in which a laminated body of a soft magnetic thin film and an insulating thin film is sandwiched between nonmagnetic materials, and having a first magnetic gap for taking in a magnetic field from a magnetic recording medium. A magnetic head body forming a path, and a part of a region of the magnetic head body that is not in contact with the magnetic recording medium,
A second magnetic gap provided with a gap larger than the first magnetic gap, and a thin film element having a magnetoresistive effect integrally disposed in the vicinity of the second magnetic gap. Magnetic head.