JP3209290B2 - Thin film magnetic head and magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head and a magnetic disk drive, and more particularly, to a magnetoresistive element (hereinafter referred to as an MR element) as a read element and an inductive magnetic transducer as a write element. The improvement of thin-film magnetic heads.

[0002]

2. Description of the Related Art Hitherto, a thin film magnetic head using an inductive thin film magnetic transducer as a read / write element has been most well known. In a thin-film magnetic head using an inductive thin-film magnetic transducer, to obtain a high read output, it is necessary to increase the relative speed between the magnetic disk and the magnetic head or to increase the number of turns of the coil. However, since magnetic disks tend to be miniaturized, an increase in read output due to an increase in relative speed does not match the actual situation. Further, the read output due to the increase in the number of turns of the coil causes an increase in the inductance and DC resistance of the coil, deteriorating the high-frequency characteristics, and making it impossible to adapt to high-speed reading. As means for solving such a problem, there has been proposed a technique in which a read element is constituted by an MR element and an inductive thin film magnetic transducer is used only for writing. Known technical documents include, for example,
JP-A-9-35088 and JP-B 64-1846.

[0003] The thin film magnetic heads disclosed in these known documents have a structure in which a write element is stacked on a read element via an isolation film. The read element includes a magnetic shield film and an MR element, and the MR element is disposed in the electrical insulating layer between the magnetic shield films. The separation film is mainly composed of a Barkhausen. It is provided for the purpose of preventing noise.
Barkhausen in a thin film magnetic head using an MR element. The noise is generated when the magnetization direction of the magnetic domain in the MR element is oriented in the direction of the write magnetic field. Barkhausen. Conventionally, as means for suppressing noise, a thicker separation film has been used.

[0004]

As described above, Barkhausen. Conventionally, as means for suppressing noise, the distance between the MR element and the writing element is reduced by the thickness of the separation film. It cannot be reduced below the value required for noise suppression.

In addition, since this type of thin-film magnetic head usually has a magnetic shield film between a write element and a read element, the distance between the MR element and the write element depends on the thickness of the magnetic shield film. It depends. One of the important factors that determine the thickness of the magnetic shield film is the saturation magnetic flux density Bs of the magnetic shield film, and the magnetic shield film cannot be made thinner than the thickness determined by the saturation magnetic flux density Bs. Specifically, the conventional magnetic shield film is made of a permalloy film having a saturation magnetic flux density Bs of about 8 (kGauss), and avoids magnetic saturation due to an external magnetic field, particularly a magnetic field generated from another magnetization reversal transition region. Therefore, a film thickness of 2 μm or more is required.

In the conventional thin-film magnetic head, the distance between the MR element and the writing element is about 9 μm, and it is difficult to reduce the distance. Because of this,
When the rotary actuator type positioning device is used, a positional shift in the track width direction occurs between the MR element and the writing element. As a means for absorbing a track shift due to a positional deviation in the track width direction, a recording track width is generally set to be wider than a reproduction track width, and the reproduction track always traces the recording track even if a position deviation occurs. . As a result, the track. The loss increases and the recording density on the magnetic disk decreases. In a conventional thin-film magnetic head, the track. The loss width is 3.2
μm or more. The above-mentioned known documents do not disclose means for solving such a problem.

Accordingly, an object of the present invention is to provide a truck. An object of the present invention is to provide a thin-film magnetic head and a magnetic disk drive capable of reducing a loss and achieving a high recording density.

[0008]

According to the present invention, there is provided a thin-film magnetic head including a slider, a read element, a write element, and an isolation film. An element, provided on the slider, the write element is provided by being stacked on the read element, and the separation film is provided between the read element and the write element. And a diamagnetic film.

[0009]

Since the readout element includes the MR element,
Unlike the case of the inductive element, the inductance is small and the high frequency characteristics are not deteriorated.

Since the separation film is provided between the read element and the write element and includes a diamagnetic film, the passage of the write magnetic field from the write element to the read element is prevented by the diamagnetic film. Therefore, the thickness of the separation film can be reduced, and the distance between the writing element and the reading element can be reduced. Diamagnetism is a characteristic that is magnetized in the opposite direction when a magnetic field is applied, that is, a characteristic whose magnetic susceptibility is negative, and is a characteristic corresponding to paramagnetism whose magnetic susceptibility is positive. The magnetic susceptibility when a magnetic field is applied to a substance is X,
If the diamagnetic term is Xd and the paramagnetic term is Xp, then X = Xd + Xp. The diamagnetic film according to the present invention is made of a diamagnetic material satisfying XpＸ0. Specific examples of the diamagnetic material include a Bi or Sb diamagnetic material or a superconducting material, preferably a high-temperature superconducting material.

Further, since the passage of the write magnetic field from the write element side to the read element side is blocked by the diamagnetic film, the thickness of the magnetic shield film can be made significantly thinner than before. Taking a general thin film magnetic head as an example,
The thickness of the magnetic shield film, which was required to be
Can be set in the range of less than. In some cases, it is possible to omit the magnetic shield film and further reduce the interval.

As a result, the distance between the writing element and the MR element is reduced to, for example, 5 μm or less, and when driven by a rotary actuator type positioning device, the area between the writing element and the MR element increases in the skew angle. The deviation in the track width direction from the element is reduced, and the track. Loss is reduced, and high-density recording becomes possible. Further, even if the skew angle is increased, the deviation in the track width direction can be reduced, so that the maximum skew angle can be increased. Therefore, it is possible to cope with a small-sized magnetic disk device in which the maximum skew angle tends to be large.

[0013]

1 is a sectional view of a thin-film magnetic head according to the present invention, and FIG. 2 is an enlarged view showing a magnetic pole arrangement of the thin-film magnetic head according to the present invention. 1 is a slider, 2 is a read element, 3
Is a write element, 4 is a separation film, and 5 is a diamagnetic film.

The slider 1 has a base portion 10 made of a ceramic structure, and an air bearing surface 101 having a high degree of flatness on the medium facing surface side. a indicates the medium running direction.

The read element 2 includes an MR element 20,
It is provided on the slider 1. The writing element 3 is provided on the reading element 2 in a stacked manner. Separation membrane 4
Is provided between the read element 2 and the write element 3 and includes a diamagnetic film 5.

As described above, since the read element 2 includes the MR element 20, unlike the inductive element, the read element 2 has a small inductance and the high-frequency characteristics do not deteriorate.

The separation film 4 is provided between the read element 2 and the write element 3 and includes the diamagnetic film 5, so that the passage of the write magnetic field from the write element 3 to the read element 2 is prevented by the diamagnetic film. Blocked by 5. For this reason, the thickness of the separation film 4 is reduced, and the write element 3 and the read element 2
Can be reduced (see FIG. 2). The standard distance d1 is about 9 μm in a conventional thin film magnetic head, but it is easy to set it to 5 μm or less according to the present invention.

As a result, the write element 3 and the MR element 20
The distance d1 between the writing element 3 and the MR element 2 is reduced in a region where the skew angle is large when driven by a rotary actuator type positioning device.
0, the deviation in the track width direction is reduced.
Loss is reduced, and high-density recording becomes possible. Further, even if the skew angle is increased, the deviation in the track width direction can be reduced, so that the maximum skew angle can be increased. Therefore, it is possible to cope with a small-sized magnetic disk device in which the maximum skew angle tends to be large.

The illustrated read element 2 includes a lower magnetic shield film 21 and an upper magnetic shield film 22 in addition to the MR element 20.

The MR element 20 includes a lower magnetic shield film 21
And the upper magnetic shield film 22 is buried in the electric insulating film 11. The MR element 20 is made of Ni-Fe, Ni
This is a thin film using a magnetic thin film material such as -Co, and is arranged between the conductor films 24 and 25 as shown in FIG.
The conductor films 24 and 25 are arranged side by side substantially in parallel with a space therebetween, and the space located on the air bearing surface 101 side defines the track width. The electric insulating film 11 is made of Al ₂ O ₃ or SiO ₂ or the like. In the read operation, a sense current is supplied to the MR element 20 through the conductor films 24 and 25, and a change in a magnetic field of a magnetic disk (not shown) is detected as a change in the electric resistance value of the MR element 20. A bias magnetic field is applied to the MR element 20 in order to flow a sense current through the conductor films 24 and 25 and to obtain a detection signal having good linearity with respect to an input magnetic field. As means for generating a bias magnetic field, a bias conductor film is formed directly on the MR element 20 and a bias is applied using a magnetic field generated by a current flowing through the bias conductor film, and a magnetic separation from the MR element 20 is performed. A soft film biasing method utilizing a magnetic field generated from a soft adjective layer (SAL) separated and arranged by a layer (MSL), wherein a thin film permanent magnet is disposed close to the MR element 20 A magnet bias system utilizing a generated magnetic field is known. Then, a change in the magnetic field of the magnetic disk is detected as a change in the electric resistance value of the MR element 20.

The lower magnetic shield film 21 is formed on the base portion 10 so as to have a substantially uniform thickness, and the upper magnetic shield film 22 is disposed in the separation film 4 at a distance from the lower magnetic shield film 21. ing. Lower magnetic shield film 2
The first and upper magnetic shield films 22 can be made of another magnetic material such as permalloy.

The write element 3 has a lower magnetic film 31, an upper magnetic film 32, a coil film 33, a gap film 34 made of alumina or the like, an insulating film 35 made of an organic resin such as a novolak resin, a protective film 36, and the like. And is stacked on the read element 2.

The distal ends of the lower magnetic film 31 and the upper magnetic film 32 are pole portions P1 and P2 opposed to each other with a gap film 34 having a small thickness therebetween, and writing is performed in the pole portions P1 and P2. Lower magnetic film 31 and upper magnetic film 3
2 are connected to each other to complete a magnetic circuit at a back gap portion opposite to the pole portions P1 and P2. A coil film 33 is formed on the insulating film 35 so as to spiral around the joint of the yoke.

The separation film 4 is an electric insulating film such as Al ₂ O ₃ or SiO ₂ , and the writing element 3 is laminated on the separation film 4. The diamagnetic film 5 is arranged in the middle of the thickness of the separation film 4.

Since the passage of the write magnetic field from the write element 3 side to the read element 2 side is blocked by the diamagnetic film 5, the thickness of the magnetic shield film 22 can be made remarkably thinner than before. Taking a general thin-film magnetic head as an example, the thickness of the magnetic shield film, which was conventionally required to be 2 μm or more,
It can be set to a range of less than 1 μm. Therefore, the distance d1 between the writing element 3 and the MR element 20 is further reduced,
When driven by the rotary actuator type positioning device, in the region where the skew angle is large, the deviation between the writing element 3 and the MR element 30 in the track width direction is reduced, and the track. Loss is reduced, and high-density recording becomes possible. Further, even if the skew angle is increased, the deviation in the track width direction can be reduced, so that the maximum skew angle can be increased.

Referring to FIG. 2, when the rotary actuator type positioning device is used, the MR element 2
As a means for absorbing a track shift due to a positional shift between the write element 3 and the write element 3 in the track width direction, a recording track width T by the lower magnetic film 31 and the upper magnetic film 32 is used.
W is set to be wider than the reproduction track width TR of the read element 2 using the MR element 20, so that the reproduction track always traces the recording track even if a positional deviation occurs. d1 is the distance between the MR element 20 and the writing element 3, G1 is the gap width, d31 is the thickness of the lower magnetic film 31, d22 is the thickness of the upper magnetic shield film 22, and d32 is the thickness of the upper magnetic film 32. , TL are the tracks .T, which are caused by providing a difference between the recording track width TW and the reproduction track width TR. Loss width, ΔT is track. Margin, G
1 is a write conversion gap.

FIG. 3 is a sectional view showing still another embodiment of the thin-film magnetic head according to the present invention. In the figure, the same reference numerals as those in FIG. 1 indicate the same components. In this embodiment, the diamagnetic film 5 constitutes an upper magnetic shield film. That is, the upper magnetic shield film independent of the diamagnetic film 5 is not provided. Therefore, in the case of this embodiment, the distance between the writing element 3 and the MR element 23 can be further reduced.

FIG. 4 is an enlarged sectional view showing still another embodiment of the thin-film magnetic head according to the present invention. In the case of this embodiment, the diamagnetic film 5 constitutes the upper magnetic shield film of the read element 2 and the lower magnetic film 31 of the write element 3
Are made of a magnetic material having a saturation magnetic flux density Bs of 10 (kGauss) or more. Conventionally, the lower magnetic film 31 is made of a permalloy film having a saturation magnetic flux density Bs of about 8 (kGauss), and has a thickness of 2 μm to secure necessary overwrite characteristics (O / W <−30 dB).
m was required. In the embodiment, the lower magnetic film 31 has a saturation magnetic flux density Bs of 10 (kGauss) or more, and can maintain a necessary overwrite characteristic (O / W <−30 dB) even when the film thickness d31 is set to less than 2 μm. . An example of a suitable magnetic material for the lower magnetic film 31 is C
o-Fe magnetic material, Co-Zr magnetic material or Fe
N-based magnetic material. The upper magnetic film 32 is the lower magnetic film 31
Or another magnetic material such as permalloy.

FIG. 5 is a diagram showing a magnetic disk drive according to the present invention. 6 is a positioning device, 7 is a magnetic disk, 8
Is a known head support device, and 9 is a thin film magnetic head according to the present invention. The magnetic disk 7 is driven to rotate in the direction of arrow a by a rotation drive mechanism (not shown). The positioning device 6 is of a rotary actuator type, supports one end of the head support device 8, and is driven at a predetermined angle on the surface of the magnetic disk 7 in the direction of the arrow b1 or b2. Thus, writing and reading to and from the magnetic disk 7 are performed on a predetermined track.

FIG. 6 is a partial front sectional view of the magnetic head device.
FIG. 7 is a partial sectional view of the bottom surface. Head support device 8
A flexible body 82 also made of a thin metal plate is attached to a free end at one longitudinal end of a support body 81 made of a thin metal plate,
The thin film magnetic head 9 is mounted on the lower surface of the flexible member 82, and a load force for pressing the thin film magnetic head 9 is applied to the magnetic disk 7. The illustrated flexible body 82 has two outer frame portions 821 and 822 extending substantially in parallel with the longitudinal axis O2 of the support 81, and a lateral portion connecting the outer frame portions 821 and 822 at an end remote from the support 81. A frame 823 and a tongue-shaped piece 82 extending from a substantially central portion of the horizontal frame 823 so as to be substantially parallel to the outer frame portions 821 and 822 and having a free end at the tip.
4, and one end opposite to the direction in which the horizontal frame 823 is located is attached to the vicinity of the free end of the support 81 by means such as welding.

On the upper surface of the tongue-shaped piece 824 of the flexible member 82, for example, a hemispherical load projection 825 is provided. The load force is transmitted.

The thin-film magnetic head 9 is attached to the lower surface of the tongue-like piece 824 by means such as bonding. Thin film magnetic head 9
Has a slider 1 and magnetic transducers 2 and 3, and the magnetic transducers 2 and 3 are provided on one end face in the length direction of the slider 1, and the length direction is in the longitudinal direction of the head support device 8. It is attached to the magnetic head support device 8 so as to match. The head support device 8 applicable to the present invention is not limited to the above embodiment. A head support device that has been proposed or may be proposed can be widely applied.

FIG. 8 is a diagram for explaining the operation of the magnetic disk device shown in FIG. In the read / write operation, the head supporting device 8 supporting the thin-film magnetic head 9 is moved by the rotary actuator type positioning device 4 to the pivot center O1.
Are driven as if swinging in the directions of arrows b1 and b2 around. Thin-film magnetic head 9 on magnetic disk 7
Is usually represented by a skew angle. In the illustrated case, the skew angle is set to 0 when the thin-film magnetic head 9 is located at the innermost circumference of the magnetic disk 7, and the skew is performed toward the outer circumference. The angle corresponds to the skew angle.

FIG. 9 shows the relationship between the recording track and the reproduction track when the skew angle = 0 when the magnetic disk drive of FIG. 5 is combined with the thin-film magnetic head according to the present invention shown in FIGS. FIGS. 10A and 10B are diagrams showing the relationship between the recording track W and the reproducing track R when the skew angle = 20 degrees in the case where the thin-film magnetic head shown in FIGS. 1 and 2 is combined with the magnetic disk device of FIG. is there. M
The distance d1 (see FIG. 2) between the R element 20 and the writing element 3 is set to 5 μm, the maximum skew angle is set to 20 degrees,
When the reproduction track width TR is 3 μm, the recording track width TW may be 5.8 μm. The loss width TL becomes 1.8 μm. Conventionally, the reproduction track width TR is 2 μm.
m, a recording track width TW of 7.7 μm is required, and a track width of 3.3 μm is required. The loss width TL occurred. Therefore, according to the invention, the track. The loss width TL can be reduced to about half of the conventional case.

Although the illustration shows a magnetic head for in-plane recording and reproduction, a magnetic head for perpendicular magnetic recording and reproduction may be used.

[0036]

As described above, according to the present invention, the following effects can be obtained. (A) Since the read element includes the MR element, the inductance value is small and the high-frequency characteristics do not deteriorate unlike the case of the inductive element. (B) Since the separation film is provided between the read element and the write element and includes the diamagnetic film, the passage of the write magnetic field from the write element to the read element is prevented by the diamagnetic film. As a result, the distance between the write element and the MR element is reduced, and when driven by a rotary actuator type positioning device, the gap between the write element and the MR element in the track width direction in a region where the skew angle is large. Is reduced and the track. Loss is reduced,
High density recording becomes possible. (C) Even if the skew angle is increased, the deviation in the track width direction can be reduced, so that the maximum skew angle can be increased.
Therefore, it is possible to cope with a small-sized magnetic disk device in which the maximum skew angle tends to be large. (D) Since the passage of the write magnetic field from the write element side to the read element side is blocked by the diamagnetic film, the thickness of the magnetic shield film is made significantly thinner or omitted than before, and the interval is further reduced. It is also possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a model of a thin-film magnetic head according to the present invention.

FIG. 2 is an enlarged view showing a magnetic pole arrangement of the thin-film magnetic head shown in FIG.

FIG. 3 is a sectional view showing a model of another example of the thin-film magnetic head according to the present invention.

FIG. 4 is a cross-sectional view showing a model of another example of the thin-film magnetic head according to the present invention.

FIG. 5 is a view showing a magnetic disk drive using the thin-film magnetic head according to the present invention.

FIG. 6 is a partial front sectional view of a magnetic head device constituting the magnetic disk device shown in FIG. 5;

7 is a partial bottom sectional view of a magnetic head device constituting the magnetic disk device shown in FIG. 5;

FIG. 8 is a diagram for explaining the operation of the magnetic disk device shown in FIG.

9 is a diagram showing a relationship between a recording track and a reproduction track when the skew angle = 0 when the magnetic disk device of FIG. 5 is combined with the thin-film magnetic head according to the present invention shown in FIGS. 1 and 2; is there.

FIG. 10 is a diagram showing a relationship between a recording track and a reproduction track when a skew angle = 20 degrees when the magnetic disk device of FIG. 5 is combined with the thin-film magnetic head according to the present invention shown in FIGS. It is.

[Explanation of symbols]

 Reference Signs List 1 slider 2 read element 20 MR element 3 write element 4 separation film 5 diamagnetic film

Claims (8)

(57) [Claims] A thin-film magnetic head including a slider, a read element, a write element, and a separation film, wherein the read element includes a magnetoresistive element, and is provided on the slider; A thin-film magnetic head, wherein the write element is provided so as to be stacked on the read element, and the separation film is provided between the read element and the write element and includes a diamagnetic film. 2. The thin-film magnetic head according to claim 1, wherein said diamagnetic film is made of a superconducting material. 3. The read element has an upper magnetic shield film on the write element side, and the diamagnetic film is disposed between the upper magnetic shield film and the write element. Item 3. The thin film magnetic head according to item 1 or 2. 4. The thin-film magnetic head according to claim 1, wherein the read element has an upper magnetic shield film on the write element side, and the diamagnetic film constitutes the upper magnetic shield film. . 5. The write element has a lower magnetic film, an upper magnetic film, and a coil film, and is provided on the read element. The lower magnetic film and the upper magnetic film
2. The magnetic head according to claim 1, wherein a tip forms a write gap, and a rear portion is connected to each other to form a magnetic circuit, and the coil film is arranged so as to go around a rear connection portion of the lower magnetic film and the upper magnetic film. 5. The thin-film magnetic head according to 2, 3, or 4. 6. The thin-film magnetic head according to claim 5, wherein the lower magnetic film is made of a magnetic material having a saturation magnetic flux density Bs of 10 (kGauss) or more. 7. The thin-film magnetic head according to claim 6, wherein the lower magnetic film is made of at least one of a Co—Fe magnetic material, a Co—Zr magnetic material, and a FeN magnetic material. 8. A magnetic disk device including a magnetic disk, a positioning device, a head support device, and a thin-film magnetic head, wherein the positioning device supports one end of the head support device, and The head is rotated at a predetermined angle on a surface, and the head support device supports the thin-film magnetic head at the other end, wherein the thin-film magnetic head is any one of claims 1 to 7. Magnetic disk device.