JPH08194920A - Magnetic recorder/reproducer - Google Patents

Abstract

PURPOSE: To obtain a magnetic head which shows a sufficient reproducing output and the low noise characteristics by a method wherein the fixing layer of the magnetoresistive layer- built film and the vertical bias film of a magnetoresistive head are made of the same material and they are antiferromagnetic films or magnetic films which are magnetized in a slant direction and the magnetoresistive head is mounted. CONSTITUTION: An electrode 40 supplies a current to the fixing layer of a magnetoresistive layer-built film 11 and takes out the electrical resistance of the magnetoresistive layer-built film 11 which is varied by an external magnetic field as an electrical signal, particularly as a voltage. On the other hand, a vertical bias film 12 gives a proper operation range and the domain control and is composed of a soft magnetic film which is coupled with an antiferromagnetic film or a ferromagnetic film by exchange coupling. The magnetizing direction 62 of the vertical bias film 62 is the same as the magnetizing direction 61 of the fixing bias of the layer-built film 11 and has an angle of, for instance, 5 deg.-40 deg. from the element height direction 65 which is perpendicular to a facing surface 63. If this angle is denoted by θ, the sin θ of the magnetization component of the vertical bias layer leaks out of the end part of the vertical bias layer 12 and gives a bias effect to the layer-built film 11. Thus a magnetic head which shows a sufficient reproducing output and the low noise characteristics can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus and a magnetoresistive effect element, and more particularly to a high recording density magnetic recording / reproducing apparatus.

[0002]

Japanese Unexamined Patent Publication (Kokai) No. 2-61572 discloses a laminated film in which the electric resistance of ferromagnetic thin films separated by an intermediate layer changes depending on the angle formed by their magnetizations, a magnetic field sensor using the same, and a magnetic recording device. Disclosure.

Japanese Unexamined Patent Publication No. 6-60336 discloses a magnetoresistive sensing system having means for making the magnetization direction of a magnetic layer perpendicular, particularly a hard magnetic film.

US Pat. No. 5,206,590 discloses a structure in which an antiferromagnetic film is in close contact with a stack of ferromagnetic films separated by a nonmagnetic film, and a hard magnetic material is in contact with the end of the stack. There is disclosure.

[0005]

In the prior art, a magnetic recording device having a sufficiently high recording density, in particular, a magnetoresistive effect element which acts on the reproducing portion with sufficient sensitivity and output to an external magnetic field, is realized. Furthermore, it was difficult to obtain good characteristics in which noise was sufficiently suppressed, and it was difficult to realize the function as a storage device.

In order to improve the recording density, it is inevitable that one unit of the recording area on the recording medium is narrowed, but this requires the miniaturization of the reproducing portion of the magnetic recording device. In this case, there are two major problems with small devices: first, the shape anisotropy of the device edges cannot be ignored, and the output tends to decrease, and secondly, the effect of the domain wall is large and noise is likely to occur. Is. As a solution to such a problem, there is a method in which a magnetoresistive effect element is arranged in the reproducing portion of a thin film magnetic head and a change in electric resistance due to the magnetoresistive effect is used as an output. In this case, what is important is that the magnetoresistive effect element requires two longitudinal biases for making the magnetic sensitive section made of the magnetoresistive effect film into a single domain and a lateral bias for keeping the output in the linear region. is there.

In recent years, it has been known that a multilayer film in which ferromagnetic metal films are laminated with a non-magnetic metal film interposed therebetween has a large magnetoresistive effect, so-called giant magnetoresistance. In this case, as for the magnetoresistive effect, the electrical resistance changes depending on the angle formed by the magnetizations of the ferromagnetic films separated by the nonmagnetic film. When this giant magnetoresistive effect is used as a magnetoresistive effect element, a structure called a spin valve has been proposed. That is, it has a structure of antiferromagnetic film / ferromagnetic film / nonmagnetic film / ferromagnetic film or hard magnetic film / nonmagnetic film / ferromagnetic film, and adheres to the antiferromagnetic film or hard magnetic film by exchange coupling. An output can be obtained by substantially fixing the magnetization of the above ferromagnetic film and rotating the magnetization of the other ferromagnetic film by an external magnetic field. The above fixing effect will be referred to as a fixed bias, and the film that produces this effect will be referred to as a fixed bias film. In order to obtain a linear output with respect to an external magnetic field, the fixed bias direction, that is, the direction of the exchange coupling anisotropy of the antiferromagnetic film or the magnetization direction of the hard magnetic film is set to the element height of the magnetic head. It needs to be in the direction.

A single magnetic domain is generally used as a method of suppressing noise caused by the domain wall movement of the magnetoresistive element.
It is effective to apply a fixed bias to the magnetoresistive film in the direction perpendicular to the direction of the magnetic field to be sensed. That is, the domain wall can be eliminated and the direction of magnetization can be set so that the magnetization process is caused by magnetization rotation. As a means for applying a fixed bias, a ferromagnetic film to which exchange coupling is applied by a hard magnetic film or an antiferromagnetic film is arranged in contact with the end of the magnetoresistive film in the track width direction, and the residual magnetization There is a method of using a static magnetic field that leaks. In this case, the direction of remanent magnetization or exchange coupling is in the track width direction.

As described above, as a magnetic head compatible with high recording density, the giant magnetoresistive effect is applied, and the spin valve type magnetoresistive effect laminated film is applied with a longitudinal bias for forming a single domain. However, a hard magnetic film or an antiferromagnetic film is required for both the fixed bias film and the longitudinal bias film of the laminated film, and the respective magnetization directions are perpendicular to each other. To apply two bias directions perpendicular to each other on the same substrate, (1) use an antiferromagnetic film on one side and a hard magnetic film on the other side, perform cooling in a magnetic field and magnetize (2) Two types of antiferromagnetic films with different Neel temperatures are used to perform cooling in a magnetic field at two stages. (3) Two types of hard magnetic films with different coercive forces are used to perform a magnetization process in two stages of magnetic fields. A complicated material structure and a magnetizing method such as performing are required.

Therefore, an object of the present invention is to provide a magnetic recording device compatible with high-density recording and a magnetoresistive effect element improved in sufficient output and low noise. More specifically, a simple structure, A material is to provide a giant magnetoresistive effect element having two biases.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to improve the recording density of a magnetic recording device, and particularly to reduce noise at a high recording density of a magnetoresistive effect element in a reproducing section. As a means for solving the problem, in the present invention, firstly, the two biases are magnetized in the same direction. Each bias film may be either an antiferromagnetic film / ferromagnetic film or a hard magnetic film, but since the bias directions are the same, it is not necessary to use the material properly.
A simple material structure in which the two bias films are made of the same material can be realized. Secondly, the direction of the bias is defined as a direction having an angle in the range of 5 ° to 40 ° with respect to the element height direction of the magnetic head. This has a function of allowing the longitudinal bias film to have a magnetization component perpendicular to the end face in contact with the magnetoresistive laminated film, and this magnetization component substantially supplies the longitudinal bias. Further, since the fixing direction of the laminated film is inclined, the position of the bias point of the response curve of the magnetic resistance can be changed, and the operation area of the head can be controlled.

As a result, for the first time, a magnetoresistive element having both output and low noise can be realized with a bias film made of a single direction and made of a material. That is, the main feature of the present invention is
A magnetic head and a magnetic recording / reproducing apparatus to which a giant magnetoresistive having a bias film in which a single antiferromagnetic film or a single hard magnetic film is magnetized at a predetermined angle from the element height direction is applied.

According to the present invention, in the magnetic recording / reproducing apparatus having the magnetoresistive effect element having the simple material structure and the simple magnetizing step as described above as the reproducing portion, high recording density, that is, recording to be recorded on the recording medium. Recording with a short wavelength and a narrow recording track width can be realized, sufficient reproduction output can be obtained, and good recording can be maintained.

[0014]

The magnetic recording / reproducing apparatus of the present invention realizes a high reproducing output with a low noise and a recording / reproducing at a particularly high recording density by a simple structure and process by the above means.

That is, in the magnetoresistive element of the present invention, one type of hard magnetic film or antiferromagnetic film also serves as the two bias films of the fixed bias and the longitudinal bias, and the magnetization directions are the same. Is easy. Since the magnetization directions of the pinned layer and the single domain domainization film are the same, they do not interfere with each other, resulting in long-term reproduction capability and low noise reliability. As a result, it is possible to obtain a magnetoresistive effect element, a magnetic head having both good sensitivity and reliability, and a magnetic recording apparatus having a high recording density.

[0016]

EXAMPLE A film constituting the magnetoresistive effect element of the present invention was produced by a high frequency magnetron sputtering apparatus as follows. The following materials were sequentially laminated on a ceramic substrate having a thickness of 1 mm and a diameter of 3 inches in an atmosphere of 3 mTorr of argon. Iron-50 at% manganese, tantalum, nickel-as a sputtering target
A target of 20 at% iron alloy, cobalt-20% platinum, and copper was used. In the laminated film, high frequency power was applied to the cathodes on which the targets were arranged to generate plasma in the apparatus, and the shutters arranged for each cathode were opened and closed one by one to sequentially form each layer. At the time of film formation, a magnetic field of about 50 Oersted is applied in parallel to the substrate by using two pairs of electromagnets orthogonal to each other in the plane of the substrate so as to have uniaxial anisotropy and the direction of the exchange coupling bias of the iron-manganese film, respectively. Was guided in the direction of.

In order to induce the anisotropy, the antiferromagnetic film was cooled in the magnetic field from around the Neel temperature of the antiferromagnetic film after the laminated film was formed, and the antiferromagnetic bias direction was induced in the magnetic field direction. Furthermore, the magnetization direction of the hard magnetic film was induced by performing a magnetization treatment of 3 kilo Oersted at room temperature.

The elements on the substrate were patterned by a photoresist process. Then, the substrate was processed into a slider and mounted on a magnetic recording device.

A specific embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a magnetic recording / reproducing apparatus using the magnetic head of the present invention. The magnetoresistive layered film 11, the vertical bias film 12, and the electrode 40 are formed on the substrate 50 which also serves as the head slider 90, and the magnetic head composed of these is positioned on the recording track 44 on the recording medium 91 to perform reproduction. The head slider 90 relatively moves on the recording medium 91 so as to face the facing surface 63 with a height of 0.2 μm or less, or to face each other in a contact state. By this mechanism, the magnetoresistive effect laminated film 11 is set at a position where the magnetic signal recorded on the recording medium 91 can be read from the leakage magnetic field 64.

The magnetoresistive layered film 11 comprises a film in which a plurality of magnetic films and a non-magnetic conductive film are alternately laminated and a fixed bias film such as an antiferromagnetic film for fixing the magnetization of a part of the magnetic film. With respect to the magnetization of the magnetic film of the other portion, the other magnetization rotates due to the external magnetic field, and the mutual angles change, so that the electric resistance changes. The magnetization rotated by the external magnetic field has its anisotropy, particularly the direction 66 of induced magnetic anisotropy, parallel to the opposing surface or inclined 5 ° to 40 ° from the parallel direction in order to facilitate rotation of the magnetization.

The electrode 40 passes a current through the magnetoresistive laminated film 11 and takes out the electric resistance of the magnetoresistive laminated film 11 which is changed by an external magnetic field as an electric signal, particularly a voltage. The longitudinal bias film 12 gives an appropriate operating range and magnetic domain control to the magnetoresistive layered film 11, and is composed of a hard magnetic film or a soft magnetic film exchange-coupled with an antiferromagnetic film. The longitudinal bias film 12 is arranged at the end of the magnetoresistive effect laminated film 11 on the track width direction 67 side.

The first feature of the present invention is that the magnetization direction 62 of the longitudinal bias film 12 and the magnetization direction 61 of the fixed bias of the magnetoresistive layered film 11 are the same, and the element height perpendicular to the facing surface 63. It is at a point having an angle of 5 ° to 40 ° with respect to the direction 65. When this angle is θ, the vertical bias film 12
The amount of sin θ of the magnetization component of leaks from the end of the longitudinal bias film 12 and can give a bias effect to the magnetoresistive effect laminated film 11. When θ is small, the bias effect is reduced, but when θ is about 5 °, the bias film can be thickened to compensate for the bias effect. Further, when θ is large, a relatively large bias effect can be given even if the magnetization component of the longitudinal bias film 12 is small, but since the angular region showing the magnetoresistive effect of the magnetoresistive effect laminated film 11 is reduced, the output is increased. Decrease. This will be described later in FIG.

FIG. 2 is a block diagram of the magnetic recording / reproducing apparatus of the present invention. A recording medium 91 that magnetically records information is rotated by a spindle motor 93, and an actuator 92 is
The head slider 90 is guided onto the track of the recording medium 91 by. That is, in the magnetic disk device, the reproducing head and the recording head formed on the head slider 90 relatively move close to a predetermined recording position on the recording medium 91 by this mechanism and sequentially write and read signals. is there. The recording signal is recorded on the medium by the recording head through the signal processing system 94, and the output of the reproducing head is obtained as a signal through the signal processing system 94. Further, when the reproducing head is moved to a desired recording track, the position on the track can be detected by using the highly sensitive output from the reproducing head, and the actuator can be controlled to position the head slider. Although one head slider 90 and one recording medium 91 are shown in this drawing, a plurality of these may be used. The recording medium 91 may record information on both sides of the disc. When information is recorded on both sides of the disk, the head sliders 90 are arranged on both sides of the recording medium.

FIG. 3 shows an example of the structure of the magnetic head of the present invention. On the head slider 90, a stock shield 82, an element film portion 10 including a magnetoresistive effect film and a bias film, an electrode 4
0, the upper shield 81, the lower core 84, the coil 41, and the upper core 83 are formed. That is, the reproducing unit and the recording core can be formed on the same slider, and recording and reproducing can be performed by the same head.

FIG. 4 is a conceptual view showing an example of the structure of the magnetoresistive effect element on the substrate surface. The magnetoresistive layered film 11 includes a magnetic layer in which the magnetization 61 is strongly fixed by inclining in the element height direction 65 and a magnetic layer induced in a direction 66 approximately parallel to the track width direction 67, and a change in electric resistance is substantially caused. Caused by rotation from the direction 66 of magnetization. Here, the magnetization induction direction 66 influences the bias point of the magnetic resistance magnetic field response curve, and may be deviated from the track width direction 67 so as to approach the direction perpendicular to the fixed bias magnetization direction 61.

FIG. 5 shows a magnetoresistive layered film 11 of the present invention.
2 is an example of a film configuration of the vertical bias film 12. The magnetoresistive layered film 11 is formed by laminating a base film 14, a first ferromagnetic film 15, a nonmagnetic film 16, a second ferromagnetic film 17, an antiferromagnetic film 18, and a protective film 19 on a substrate 50. Become. The vertical bias film 12 is in contact with both ends of the laminated film 11, and is formed by laminating a base film 21, a ferromagnetic film 23, an antiferromagnetic film 24, and a protective film 25. The second ferromagnetic film 17 and the antiferromagnetic film 18 are in an exchange coupling state and generate a unidirectional anisotropic bias to substantially fix the magnetization direction of the first ferromagnetic film 15. The ferromagnetic film 23 and the antiferromagnetic film 24 are in an exchange coupling state and generate a unidirectional anisotropic bias to substantially fix the magnetization direction of the ferromagnetic film 23. The magnetoresistive effect occurs between the second ferromagnetic film 17 whose magnetization direction is substantially fixed and the first ferromagnetic layer whose magnetization can be rotated by an external magnetic field, as a function of the angle formed by the magnetization. To do.

FIG. 6 shows a magnetoresistive layered film 11 of the present invention.
And another example of the film configuration of the vertical bias film 12. The magnetoresistive layered film 11 is formed by laminating a base film 14, a hard magnetic film 13, a first ferromagnetic film 15, a nonmagnetic film 16, a second ferromagnetic film 17, and a protective film 19 on a substrate 50. . The vertical bias film 12 is in contact with both ends of the laminated film 11 and is formed by laminating a base film 21, a ferromagnetic film 23, and a hard magnetic film 26. Hard magnetic film 1
3 and 26 are processed by applying a strong magnetic field to magnetize,
The magnetization directions of the first ferromagnetic film 15 and the ferromagnetic film 23 adjacent to each other are substantially fixed. The magnetoresistive effect occurs between the first ferromagnetic film 15 whose magnetization direction is substantially fixed and the second ferromagnetic layer whose magnetization can be rotated by an external magnetic field as a function of the angle formed by the magnetization. To do.

FIG. 7 shows an example of a magnetic field response curve at θ = 0 ° of the magnetic head of the present invention. There are many steps and hysteresis in the response curve. It is considered that this is because the longitudinal bias film does not have the bias effect and the domain wall is generated in the magnetoresistive effect laminated film 11.

FIG. 8 is a magnetic field response curve of a magnetic head magnetized at θ = 10 °. The response curve has good characteristics that its center is near the zero magnetic field, its linear region is wide, and its hysteresis is extremely small.

FIG. 9 shows the angle θ of the magnetic head of the present invention,
It is the figure which showed the output of a response curve, and the relationship with coercive force.
It can be seen that the coercive force was 2 Oersted or less when θ was 5 ° or more, and the hysteresis was sufficiently suppressed. The output gradually decreased as θ increased, and became 1/2 or less when θ was 40 ° or more compared with θ = 0 °. That is, in the present invention, the output and low noise can be balanced by setting the magnetizing direction to be inclined by 5 ° to 40 ° from the element height direction.

As described above, as a result of testing the magnetic head of the present invention and the magnetic recording / reproducing apparatus equipped with the same, sufficient output and low noise characteristics were exhibited.

[0032]

As described above in detail, according to the present invention, it is possible to obtain a magnetic head having a sufficient reproduction output and low noise characteristics and a highly reliable high density magnetic recording / reproducing apparatus.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a configuration diagram of a magnetic recording / reproducing apparatus of the present invention.

FIG. 3 is a conceptual diagram showing a configuration example on a substrate of a magnetic head of the present invention.

FIG. 4 is a conceptual diagram showing a configuration example on a base of a magnetoresistive effect element of the present invention.

FIG. 5 is a conceptual diagram showing a first example of a film configuration of a magnetoresistive laminated film and a bias film of the present invention.

FIG. 6 is a conceptual diagram showing a second example of the film configuration of a magnetoresistive layered film and a bias film of the present invention.

FIG. 7 is an example of a magnetic field response curve at θ = 0 ° of the magnetic head of the present invention.

FIG. 8 is an example of a magnetic field response curve at θ = 10 ° of the magnetic head of the present invention.

FIG. 9 is an example showing the relationship between the angle θ and the output of the response curve and the coercive force of the magnetic head of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Element film part, 11 ... Magnetoresistive laminated film, 12 ... Longitudinal bias film, 13 ... Hard magnetic film, 14 ... Underlayer film, 15 ... First ferromagnetic film, 16 ... Nonmagnetic film, 17 ... Second Ferromagnetic film, 18 ... Antiferromagnetic film, 19, 25 ... Protective film, 21 ... Underlayer film, 23 ... Ferromagnetic film, 24 ... Antiferromagnetic film, 40 ... Electrical terminal, 50 ... Substrate, 60 ... Magnetic field Sensing direction, 61 ... Magnetization direction of fixed bias film, 62 ... Magnetization direction of longitudinal bias film, 63 ... Opposing surface, 64 ... Magnetic field from recording medium, 65 ...
Element height direction, 66 ... Magnetization induction direction, 67 ... Track width direction, 90 ... Slider, 91 ... Recording medium, 92 ... Actuator, 93 ... Spindle motor, 94 ... Signal processing circuit system.

Claims (2)

[Claims] 1. A magnetic recording / reproducing apparatus comprising a disk having a ferromagnetic recording medium on which a signal is magnetically recorded, and a magnetic head which is close to the disk and detects a magnetic field leaking from the recording medium. The magnetic head comprises a laminated film in which a first antiferromagnetic film / a ferromagnetic film / a non-magnetic conductive film / a ferromagnetic film are sequentially laminated, and the electric resistance of which changes depending on the angle between the magnetizations of the ferromagnetic films. An electric terminal for applying a current thereto, and a bias film in which a second antiferromagnetic film / ferromagnetic film which is in contact with an end of the laminated film in the track width direction and is adjacent to each other are sequentially laminated, The first and second antiferromagnetic films have exchange coupling with the laminated ferromagnetic films, respectively, and are unidirectionally different in the same direction having an angle of 5 ° to 40 ° with respect to the element height direction of the magnetic head. A magnetic recording / reproducing apparatus characterized by having an orientation. 2. A magnetic recording / reproducing apparatus having a magnetic head for detecting a magnetic field leaking from a recording medium in the vicinity of a disk having a ferromagnetic recording medium for magnetically recording a signal. Hard magnetic film / ferromagnetic film / non-magnetic conductive film / ferromagnetic film, in which the electric resistance changes depending on the angle between the magnetizations of the ferromagnetic films, and an electric terminal for applying a current to the laminated film. And a bias film made of a second hard magnetic film in contact with the end of the laminated film in the track width direction, and the residual magnetization of the first and second hard magnetic films is the element height of the magnetic head. 5 ° to the vertical direction
A magnetic recording / reproducing apparatus, which is oriented in the same direction having an angle of 40 °.