JPH11328629A - Magnetoresistance effect head and its manufacture, and magnetic memory using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a magnetic memory of a high surface density by restricting noises because of a magnetic yoke at a magnetic head using a magnetoresistance effect element. SOLUTION: A magnetic body pattern to be a lower face magnetic core is arranged on a base body 10. A magnetic body pattern to be a side face magnetic core is placed oppositely via an excitation coil 16. The excitation coil is placed to be electrically insulated from the lower face magnetic core and the side face magnetic core. A magnetoresistance effect element is installed and a pair of magnetic yokes 12, 13 are arranged via a magnetic gap 15. In the thus-constituted magnetoresistance effect head, the magnetic yokes 12, 13 set in the vicinity of a magnetic recording medium are formed of a magnetic thin film. When a magnetic flux from the medium passes the magnetic yokes 12, 13 to reach the magnetoresistance effect element, the component of the magnetic flux reaching the magnetoresistance effect element in a perpendicular direction to a film face of the magnetic thin film constituting the magnetic yokes 12, 13 becomes larger than the in-plane component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing head utilizing a magnetoresistance effect, a method of manufacturing the same, and a magnetic storage device using the same.

[0002]

2. Description of the Related Art With the miniaturization and large capacity of magnetic recording media, magnetoresistive heads (hereinafter referred to as MR heads) have been put to practical use as suitable magnetic heads. Regarding the technical contents of this MR head, for example, "IE
EE Trans.on Magn, .MAG7 (1970) 150 ''
netoresistivity Readout Transducer ".

In recent years, a giant magnetoresistance effect (hereinafter referred to as G
GMR heads using MR) have attracted attention.
In this GMR head, in particular, the change in electric resistance is proportional to the cosine between the magnetization directions of two adjacent magnetic layers, and the magnetoresistance effect generally called a spin valve effect causes a large resistance change with a small operating magnetic field. Next generation MR
It is expected as a head. Regarding the MR head using the spin valve effect, for example, "IEEETrans.on
Magn, Vol. 30, No. 6 (1994) 3801 ''
n, Fabrication & Testing of Spin-Valve Read Heads f
or High Density Recording ".

[0004] Among them, the magnetization of one of the two magnetic layers that generate the spin valve effect is affected by the exchange coupling generated by laminating an antiferromagnetic film on this magnetic layer, so that the magnetic head is sensitive. The magnetization fixed layer is fixed so that the magnetization direction is substantially aligned with the direction of the medium magnetic field that enters the magnetic portion. The other magnetic layer adjacent to the magnetization fixed layer via a conductive layer such as Cu is a magnetization free layer that can freely change the magnetization direction with respect to the magnetic field from the magnetic recording medium.

The above MR head or GMR head is used as a composite magnetic head shown in FIG. FIG. 9 is a schematic view of the structure of the composite magnetic head as viewed from the surface facing the magnetic recording medium.

Referring to FIG. 9, a magnetic separation layer 93 and a magnetic separation layer 97 made of an insulator are provided between a pair of opposed magnetic shields 92 and 98 which are sequentially laminated on a ceramic 91 serving as a slider. Through the central area 9
As 6, a laminated structure for generating a magnetoresistance effect is arranged, and an end region 94 and an end region 95 for supplying a current and a bias magnetic field thereto are formed at both ends of the central region 96. The magnetic information recorded on the magnetic recording medium is reproduced by the above MR element (reproducing head).

Further, as a recording head, the magnetic shield 98 is shared as one magnetic pole film, and the magnetic shield 98
The other magnetic pole 910 is laminated in parallel with the magnetic shield 98 via a magnetic gap 99 on the surface opposite to the surface in contact with the element. A coil (not shown) sandwiched between insulators is disposed slightly behind the magnetic shield 98 and the magnetic pole 910, and an alumina layer 911 for protecting these laminated films is provided.
Cover with. Then, magnetic information is recorded on a magnetic recording medium disposed near by the magnetic shield 98 magnetized by the magnetic field generated from the coil, that is, the magnetic flux leaking from the magnetic gap 99 between the magnetic pole films. .

The above-described structure in which the reproducing head and the recording head are stacked is a magnetoresistive effect type composite head which has been mainly used conventionally.

FIG. 8 is an external view showing an example of a conventional magnetoresistive head. FIG. 9 shows a head element of the magnetoresistive head shown in FIG.
FIG. In FIG. 8, the upper side in the figure is the surface facing the magnetic recording medium.

Referring to FIGS. 8 and 9, a composite head element 81 is formed on a side surface of a slider 82, and an electrode 83 supplies current to a coil for generating a recording magnetic field and a reproducing MR element of the composite head element 81. Done. When the composite head element 81 is viewed from the upper side of FIG. 8, it becomes as shown in FIG.

[0011]

However, in recent years, the distance between the magnetic recording medium and the head element has become extremely short with the improvement in recording density, and in the near future, the magnetic recording medium and the head element will come into contact with each other. In addition, it is required to perform a recording / reproducing operation while sliding. In this contact recording / reproducing environment, in the case of a magnetoresistive head, a phenomenon called thermal asperity occurs in which the electrical resistance of the head element changes due to a rise in temperature due to sliding friction and an erroneous reproduction signal is generated. It is a big problem. Due to this phenomenon,
In fact, the conventional magnetoresistive head shown in FIGS. 8 and 9 cannot be used in an environment where the head is in sliding contact with a magnetic recording medium.

Here, in order to use an MR head or a GMR head in a state of sliding in contact with a magnetic recording medium,
It is necessary that these element portions are retracted from the contact portion with the magnetic recording medium to such an extent that they are not affected by the rise in temperature due to sliding friction. A magnetic yoke (magnetic circuit) for guiding the magnetic flux from the magnetic recording medium is required.

Examples of the use of this magnetic yoke include, for example, JP-A-08-017019 and JP-A-10-0.
No. 03618 is disclosed. Each of these has a characteristic structure, but generally employs the structure shown in FIG. That is, the magnetic yokes 102 and 10 that guide the magnetic flux 106 from the magnetic recording medium 105 to the MR element 101
Reference numerals 3 and 104 denote magnetic thin films, which are magnetic recording media 105.
From the magnetic thin film passes in the in-plane direction of the magnetic thin film.

At this time, since the magnetic thin film has a magnetic domain structure, the magnetic flux 106 is generated by the magnetic yokes 102, 103, and 103.
When passing in the in-plane direction of the magnetic thin film 104, Barkhausen noise due to magnetic domains is generated. Especially,
When the width of the magnetic yoke is narrowed to cope with high-density recording, magnetic domain disturbance becomes remarkable, and Barkhausen noise increases. Therefore, conventionally, an MR head using a magnetic yoke to cope with high-density recording It was impossible to achieve.

According to the present invention, there is provided a magnetic head which solves such a problem and which can be used in a high-density recording area in a state where an MR head or a GMR head having a high reproduction efficiency is slid in contact with a magnetic recording medium. And a method of manufacturing the same. A magnetic storage device equipped with the magnetic head and recording at least 10 gigabits per square inch by using a magnetic thin film medium, and a magnetic powder coating medium. It is intended to provide a magnetic storage device which performs recording at 0.5 gigabits or more per square inch by using the magnetic storage device.

[0016]

SUMMARY OF THE INVENTION The present invention provides a lower surface magnetic core made of a magnetic material pattern, a side magnetic core made of a magnetic material pattern opposed across an exciting coil, the lower surface magnetic core and the side magnetic core. An exciting coil electrically insulated from the magnetic recording medium, a magnetoresistive element for reading a magnetic signal recorded on a magnetic recording medium, and the magnetoresistive element disposed near the magnetic recording medium via a magnetic gap. A pair of magnetic yokes for sequentially guiding a magnetic flux to a substrate, wherein the pair of magnetic yokes is formed of a magnetic thin film, and the magnetic flux from the magnetic recording medium is supplied to the pair of magnetic yokes. When the magnetic flux reaches the magnetoresistive element after passing through, the magnetic flux reaching the magnetoresistive element is applied to the film surface of the magnetic thin film forming the pair of magnetic yokes. Straight direction component, and wherein the greater than the in-plane direction component. Further, the magnetic gap is
It is characterized by writing (recording) and reading (reproduction) of magnetic information.

Further, the magnetoresistive head according to the present invention comprises:
The magnetic yoke is made of a magnetic thin film having a saturation magnetization of 10 kG or more.
A film comprising an Ni film, an amorphous film mainly containing Co, a microcrystalline film mainly containing Fe or Co, or the like.

Further, the invention is characterized in that the magnetoresistance effect element uses an anisotropic magnetoresistance effect such as a NiFe film. Further, the magnetoresistance effect of the magnetoresistance effect element is such that the magnetization of one of the two adjacent magnetic layers is fixed to form a fixed magnetization layer, and the other magnetic layer is free to the medium magnetic field. By becoming a magnetization free layer that can rotate the magnetization,
The spin valve effect corresponds to the cosine between the magnetization directions of the two adjacent magnetic layers.

Also, the width of at least one of the pair of magnetic yokes via the magnetic gap, which defines the recording track width in contact with the magnetic gap, is 1 μm or less. In addition, for a pair of magnetic yokes via the magnetic gap, a magnetic pattern serving as the lower magnetic core,
In addition, the magnetic pattern serving as the side magnetic core is magnetically separated. Further, on the same substrate on which the magnetoresistive head is formed,
A recording / reproducing amplifier is formed.

Next, in the method of manufacturing a magnetoresistive head according to the present invention, a step of forming a magnetic pattern serving as a lower magnetic core on a ceramic wafer serving as a base, and opposing each other with an exciting coil interposed therebetween. A step of forming a magnetic pattern to be a side magnetic core, a step of forming an exciting coil electrically insulated from the lower magnetic core and the side magnetic core, and a step of forming a magnetoresistive element. A magnetic gap for introducing a magnetic flux from a recording medium into the magnetoresistive element and supplying a magnetic flux from the lower magnetic core and the side magnetic core excited by the exciting coil to the recording medium as a recording magnetic field; A step of forming a pair of magnetic yokes via the step.

Further, the step of forming the magnetoresistive element includes the steps of forming a magnetoresistive element, patterning the magnetoresistive element with a photomask, and forming the magnetoresistive element using the photomask. Forming a bias film and an electrode film for supplying a bias magnetic field and a sense current to the magnetoresistive effect element pattern by lift-off.

The method may further include a step of forming a recording / reproducing amplifier on the wafer serving as the base.

Further, a magnetic storage device using the magnetoresistive head according to the present invention is a magnetic storage device wherein the magnetoresistive head is brought into contact with a magnetic recording medium to perform recording and reproduction. The magnetoresistive head is characterized in that the effective recording width on the magnetic recording medium is larger than the effective reproducing width.

In the magnetic storage device, the magnetic recording medium is a magnetic thin film, the coercive force of the magnetic thin film is 2500 Oe or more, and the recording density on the magnetic recording medium is 1 square inch per square inch. It is characterized by being 10 gigabits or more.

Further, in the magnetic storage device, the magnetic recording medium is a coating film composed of a magnetic powder and a binder, the magnetic coating film has a coercive force of 1500 Oe or more, and has a recording density on the magnetic recording medium. Is 0.55 gigabits per square inch or more.

[0026]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a magnetoresistive head according to an embodiment of the present invention.

Referring to FIG. 1, a base 1 serving as a slider
Numeral 0 is a composite ceramic comprising Al ₂ O ₃ and TiC, and the magnetic core 11 is made of Ni formed by plating.
It is made of an Fe film. The magnetic yoke 12 and the magnetic yoke 13 are arranged on a magnetic recording medium facing surface (ABS surface) 19 for sensing a recorded magnetic signal through a magnetic gap 15. Become. The thickness of the NiFe film is 1 μm to 5 μm, and the gap length is 0.05 μm to 0.4 μm. A magnetic gap 1 is provided on the spin valve element 14 as a magnetoresistive element.
In order for the magnetic flux flowing into the magnetic yokes 12 and 13 from the magnetic flux 5 to efficiently flow into the spin valve element, the non-magnetic pattern 1
7 are formed.

Next, FIG. 2 will be referred to for describing the spin valve element 14 of the magnetoresistive head according to the present invention. FIG. 2 is a diagram of the magnetoresistive head according to the present invention as viewed from the surface facing the magnetic recording medium (ABS surface). Referring to FIG. 2 in conjunction with FIG. 1, the spin valve film pattern 110 includes:
It is sandwiched between laminated film patterns 111 of a permanent magnet film (not shown) for applying a bias and an electrode film (not shown) for supplying a current. Are electrically insulated.

The spin valve film pattern 110 is made of Ta / N
It is composed of a laminated film of iFe / Cu / CoFe / NiMn. The magnetic yokes 12 and 13 are controlled to a width that defines a track width in the vicinity of the magnetic gap 15 that is used for both recording and reproduction, and the width is 1 μm or less. The coil 16 is insulated from the magnetic core 11, the magnetic yoke 12, the magnetic yoke 13, and the spin valve element 14. The magnetic yokes 12 and 13 are made of the alumina film 1.
8, the surface facing the magnetic recording medium (ABS surface) 19
Is flattened.

When the recording / reproducing characteristics of the magnetoresistive head of the present invention manufactured in such a configuration were evaluated, the distortion (Uygle) of the reproduced waveform caused by Barkhausen noise was sufficiently about 1%. It was a small standard. This is because, as shown in FIG. 3, the magnetic flux 113 flowing from the magnetic recording medium 112 into the magnetic yokes 12, 13 flows mainly along the thickness direction of the magnetic yoke, so that the influence of the magnetic domains formed in the in-plane direction of the magnetic yoke. Is considered to be due to the effective reduction of

That is, in the magnetoresistive head according to the present invention, when the magnetic flux from the magnetic recording medium passes through the magnetic yoke and reaches the magnetoresistive element, the magnetic yoke of the magnetic flux reaching the magnetoresistive element is used. The mode in which the magnetic flux from the magnetic recording medium passes in the in-plane direction of the magnetic thin film is used by setting the component in the direction perpendicular to the film surface of the magnetic thin film to be configured to be larger than the in-plane direction component. Barkhausen noise was significantly suppressed as compared with the conventional yoke type magnetoresistive head.

This is due to the fact that the magnetic flux passes in the direction perpendicular to the film surface, thereby reducing the necessity for accommodating the movement of the magnetic domain wall, as compared with the conventional method in which the magnetic flux passes in the film surface direction of the magnetic yoke. .

In the magnetoresistive head according to the present invention, the magnetic yokes 12 and 13 are made of CoFeNi.
Film, amorphous film containing Co as a main component such as CoTaZr film, FeTaN film, FeTa or Cn such as CoTaN film.
Similar results can be obtained by using a microcrystalline film containing o as a main component. The same effect can be obtained when the spin valve film is a NiFe film or the like which is a normal anisotropic magnetoresistive film.

Next, a method of manufacturing a magnetoresistive head according to the present invention will be described with reference to FIG. FIG.
FIG. 1H is a diagram showing a manufacturing process of the magnetoresistive head element of the present invention.

FIG. 4A shows a step of processing the base 10 to be a slider. In this processing, ion beam etching is performed using a photoresist having a desired pattern shape as a mask.

FIG. 4B shows a step of forming the magnetic core 11. A NiFe film pattern is formed by using a frame plating method. Thereafter, ion beam etching is performed using the photoresist as a mask to form a concave shape.

FIG. 4C shows a step of forming a coil 16 for generating a recording magnetic field covered with an insulator. In this step, a photoresist is applied and patterned, and a Cu coil 16 is formed by frame plating.
Step of forming photoresist, applying photoresist to coil 1
6 is coated.

FIG. 4D shows a step of forming the spin valve element 14. This step includes a step of forming a spin valve film, a step of patterning the spin valve film using a photomask, a bias film for supplying a bias magnetic field and a sense current to the spin valve film pattern using the photomask, and Forming an electrode film by lift-off. The spin valve element 14 is insulated from the magnetic core 11 and the magnetic yokes 12, 13 described later.

FIG. 4E shows that the magnetic flux flowing from the magnetic gap into the magnetic yoke flows into the spin valve element 14 efficiently so that the non-magnetic pattern 1
7 is a step of forming the same. The non-magnetic pattern is formed by patterning a photoresist and performing a heat treatment so as to form an arc.

FIG. 4F shows a step of forming the magnetic yokes 12 and 13 for introducing a magnetic field to the spin valve element 14. When a magnetic pole material such as NiFe or CoFeNi is used by a plating method, a step of forming the magnetic yoke 12 by a frame plating method, a step of forming a non-magnetic layer for forming the magnetic gap 15 by a sputtering method of alumina, etc. This is a step of forming the magnetic yoke 13 by plating. At this time, in order to reduce the width of the magnetic yoke near the gap to 1 μm or less, ion beam etching is performed from the surface facing the magnetic recording medium in the final step or the like.
A desired track width can be achieved.

FIG. 4G shows a step of forming an alumina film 18 for protecting the spin valve element with a nonmagnetic insulating film such as an alumina film. This is formed by sputtering with a desired bias applied to the substrate.

FIG. 4H shows the magnetic recording medium facing surface (AB
This is a step of polishing the S surface 19 to determine the depth of the magnetic gap 15 and flattening the medium facing surface. In order to determine the depth of the magnetic gap 15, when forming the alumina film 18 by sputtering in the step of FIG. 4G, an alumina film corresponding to a target magnetic gap depth is formed. After the film formation is stopped and a pattern such as a photoresist is formed, an alumina film is further formed.

Thus, when the polishing is performed in the step of FIG. 4H, the desired depth of the magnetic gap 15 can be obtained by the disappearance of the pattern of the photoresist or the like formed in the step of FIG. Further, in the step of FIG.
Then, an electrode 20 for electrically connecting the coil for generating a recording magnetic field and the spin valve element is formed by Cu plating.

The substrate 10 serving as a slider is made of Al ₂
Ceramics other than the composite ceramic consisting of O ₃ and TiC may be used, or Si may be used. Further, the magnetoresistance effect element according to the present invention may be other than the one using the spin valve film, and may be one using an anisotropic magnetoresistance effect film such as a NiFe film.

As shown in FIG. 5, the magnetic core 11 is magnetically separated from the pair of magnetic yokes 12 and 13 via the magnetic gap of the present magnetic head. Since the amount of magnetic flux flowing into the device can be increased, it is advantageous for increasing output.

FIG. 6 is an external view showing an example of a magnetoresistive head according to the present invention. Referring to FIG. 6, the read / write element 61 is flattened on a rail surface 63 on a base 62. With this magnetoresistive head, even if the magnetic yoke is narrowed in response to the increase in track density, the distortion (Uygle) of the reproduced waveform due to Barkhausen noise can be obtained at a sufficiently small level of about 1%, A magnetic head that uses MR or GMR elements with high reproduction efficiency and does not generate erroneous signals due to contact heating even when in contact with the magnetic recording medium and is not affected by some wear I do.

FIG. 7 is an external view showing another example of the magnetoresistive head of the present invention. In the case of FIG.
This is an example in which a recording / reproducing amplifier 64 is formed on a base 62. The amplifier 64 can be easily formed if the base 62 is made of Si. It can be formed by forming it. By arranging the amplifier 64 near the recording / reproducing element as in this example, it is possible to realize a magnetoresistive head with improved high-frequency characteristics and a high data transfer speed.

FIG. 11 is a configuration diagram showing a magnetic storage device equipped with the magnetoresistive head of the present invention. Referring to FIG. 11, a magnetic head 1103 of the present invention is provided with a suspension 1104 and an arm 110 facing a magnetic recording surface of a magnetic recording medium 1102 rotated by a drive motor 1101.
5 and the voice coil motor (VC
M) Positioning is performed at 1106.

The recording / reproducing operation is performed by a signal from a recording / reproducing channel 1107 to the magnetic head. The recording / reproducing channel 1107, the voice coil motor (VCM) 1106 for positioning the magnetic head 1103, and the magnetic recording medium 1102 are controlled. Drive motor 1101 to rotate
Operate under the control of the control unit 1108.

Here, in the above magnetic storage device, the recording layer of the magnetic recording medium is a magnetic thin film (thin film type medium),
When the coercive force is 2500 Oe or more, a magnetic storage device having a recording density on a magnetic recording medium of 10 gigabits per square inch or more is realized. At this time, the recording track width becomes slightly larger than the width of the magnetic pole near the magnetic gap due to the magnetic flux leaking from the magnetic yoke. Also, since the reproduction width is the width of the magnetic pole, wide recording and narrow reproduction are effectively realized.

Further, in the above magnetic storage device, the recording layer of the magnetic recording medium is a coating film composed of magnetic powder and a binder (coating type medium), and its coercive force is 1500 Oe or more. A magnetic storage device having a recording density of 0.55 gigabits per square inch or more is realized.

[0052]

As described above, according to the present invention, even if the magnetic yoke is narrowed in response to the increase in track density, the distortion (Uygle) of the reproduced waveform due to Barkhausen noise is sufficiently small, and A magnetoresistive head that does not generate an erroneous signal due to contact heating even when in contact with a magnetic recording medium using a highly efficient MR element or GMR element, and is not affected by some wear. Can be provided. Further, a magnetic storage device using this magnetic head can realize a magnetic storage device having a recording density on a magnetic recording medium of 10 gigabits per square inch or more.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a magnetoresistive head according to the present invention.

FIG. 2 is a diagram of a magnetoresistive head according to the present invention as viewed from a surface facing a medium magnetic recording medium.

FIG. 3 is a diagram showing how a magnetic flux flows during reproduction of the magnetoresistive head of the present invention.

FIG. 4 is a diagram showing a manufacturing process of the magnetoresistive head of the present invention.

FIG. 5 is a side view showing a magnetoresistive head according to the present invention.

FIG. 6 is an external view showing a magnetoresistive head according to the present invention.

FIG. 7 is an external view showing a magnetoresistive head according to the present invention.

FIG. 8 is an external view showing an example of a conventional magnetoresistive head.

FIG. 9 is a view of the magnetoresistive head shown in FIG. 8 as viewed from a magnetic recording medium facing surface (ABS surface).

FIG. 10 is a diagram showing how a magnetic flux flows during reproduction of a magnetoresistive head using a conventional magnetic yoke.

FIG. 11 is a configuration diagram showing a magnetic storage device equipped with a magnetoresistive head of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Base 11 Magnetic core 12, 13 Magnetic yoke 14 Spin valve element 15 Magnetic gap 16 Coil 17 Nonmagnetic pattern 18 Alumina film 19 Magnetic recording medium facing surface (ABS surface) 20 Electrode 61 Recording / reproducing element 62 Base 63 Rail surface 64 Amplifier 81 Composite head element 82 Slider 83 Electrode 91 Ceramic 92,98 Magnetic shield 93,97 Magnetic separation layer 94,95 End area 96 Central area 99 Magnetic gap 910 Magnetic pole film 911 Alumina layer 101 MR element 102,103,104 Magnetic yoke 105, 112 Magnetic recording medium 106, 113 Magnetic flux 110 Spin valve film pattern 111 Stacked film pattern 1101 Drive motor 1102 Magnetic recording medium 1103 Magnetic head 1104 Suspension 1105 Arm 1106 Voice coil Motor (VCM) 1107 Recording / playback channel 1108 Control unit

Claims (19)

[Claims] A bottom magnetic core made of a magnetic material pattern;
A side surface magnetic core made of a magnetic pattern opposed to each other with an excitation coil interposed therebetween; an excitation coil electrically insulated from the lower surface magnetic core and the side surface magnetic core; and a magnetic signal recorded on a magnetic recording medium. And a pair of magnetic yokes, which are arranged near the magnetic recording medium and guide a magnetic flux to the magnetoresistive element via a magnetic gap, are sequentially formed on a substrate. In, the pair of magnetic yokes is made of a magnetic thin film, and when the magnetic flux from the magnetic recording medium passes through the pair of magnetic yokes and reaches the magnetoresistive element,
A magnetoresistive head, wherein a component of a magnetic flux reaching the magnetoresistive element in a direction perpendicular to a surface of the magnetic thin film forming the pair of magnetic yokes is larger than an in-plane component. 2. The magnetoresistive head according to claim 1, wherein the magnetic gap serves both for writing (recording) and reading (reproducing) magnetic information on the magnetic recording medium. 3. A pair of magnetic yokes each having a saturation magnetization of 10.
2. A magnetic thin film having a thickness of kG or more.
A magnetoresistive head according to any of the preceding claims. 4. The magnetoresistive head according to claim 3, wherein said pair of magnetic yokes is made of a NiFe film or a Co—Fe—Ni film. 5. The magnetoresistive head according to claim 3, wherein said pair of magnetic yokes are made of an amorphous film containing Co as a main component. 6. A magnetoresistive head according to claim 3, wherein said pair of magnetic yokes is made of a microcrystalline film containing Fe or Co as a main component. 7. The method according to claim 1, wherein at least one of the pair of magnetic yokes defining a recording track width in contact with a magnetic gap has a width of 1 μm or less.
The magnetoresistive head according to any one of claims 1 to 4. 8. A magnetic pattern wherein the magnetic pattern serving as the lower magnetic core and the magnetic pattern serving as the side magnetic core are magnetically separated with respect to the pair of magnetic yokes. Item 8. The magnetoresistive head according to any one of Items 1 to 7. 9. The magnetoresistive head according to claim 1, wherein said magnetoresistive element uses an anisotropic magnetoresistive effect. 10. The magnetoresistive head according to claim 9, wherein the material causing the anisotropic magnetoresistance effect is a NiFe film. 11. The magnetoresistive effect of the magnetoresistive element is such that one of two adjacent magnetic layers has a fixed magnetization and becomes a fixed magnetization layer, and the other can freely rotate a magnetization with respect to a medium magnetic field. 11. The magnetoresistive head according to claim 1, wherein the magnetoresistive head has a spin valve effect to be a magnetization free layer. 12. The magnetoresistive head according to claim 1, wherein a recording / reproducing amplifier is formed on the same substrate on which the magnetoresistive head is formed. Magnetoresistive head. 13. A method of manufacturing a magnetoresistive head, which is sequentially formed on a wafer serving as a base by the following steps, wherein: a step of forming a magnetic material pattern serving as a lower surface magnetic core; A step of forming a magnetic material pattern to be a side magnetic core facing and sandwiching the same; a step of forming an exciting coil electrically insulated from the lower magnetic core and the side magnetic core; Forming a magnetic flux through a magnetic gap for introducing magnetic flux from a recording medium to the magnetoresistive element and supplying magnetic flux from the lower surface magnetic core and the side magnetic core excited by the exciting coil. Forming a pair of magnetic yokes. 14. A step of forming the magnetoresistive element, the steps of forming a magnetoresistive element, patterning the magnetoresistive element with a photomask, and using the photomask to form the magnetoresistive element. 14. A method of manufacturing a magnetoresistive head according to claim 13, further comprising the step of: forming a bias film and an electrode film for supplying a bias magnetic field and a sense current to the magnetoresistive element pattern by lift-off. 15. The method of manufacturing a magnetoresistive head according to claim 13, further comprising the step of forming a recording / reproducing amplifier on the wafer serving as the base. 16. A recording / reproducing method comprising mounting the magnetoresistive head according to any one of claims 1 to 12, and contacting and sliding the magnetoresistive head with a magnetic recording medium. Magnetic storage device. 17. A magnetoresistive head according to claim 1, wherein an effective recording width on a magnetic recording medium is larger than an effective reproducing width. Magnetic storage device. 18. The magnetic recording medium comprises a magnetic thin film, the coercive force of the magnetic thin film is 2500 Oe or more, and the recording density on the magnetic recording medium is 10 gigabits per square inch or more. 18. The magnetic storage device according to claim 16, wherein: 19. The magnetic recording medium is a magnetic coating comprising magnetic powder and a binder, the coercive force of the magnetic coating is 1500 Oe or more, and the recording density on the magnetic recording medium is 1 square inch. 18. The magnetic storage device according to claim 16, wherein the capacity is 0.5 gigabits or more.