JP2007095304A - Magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable magnetic head which prevents deletion after recording. <P>SOLUTION: The magnetic head includes a thin film magnetic head for vertical magnetic recording which is provided with; a main magnetic pole having an end part for facing a magnetic recording medium and a coil for magnetizing the main magnetic pole. In this case, the end part or at least part of the main magnetic pole is a soft magnetic multilayer film which contains a laminated body having a first ferromagnetic film, a second ferromagnetic film and an antiparallel coupling layer formed between the first and second ferromagnetic films. The antiparallel coupling layer performs interlayer coupling between the first ferromagnetic film and the second ferromagnetic film antiferromagnetically. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic head, and more particularly to a perpendicular magnetic recording type magnetic head.

Patent Document 1 describes a magnetic field sensor using a magnetic film coupled in antiparallel.
Non-Patent Document 1 describes that antiparallel coupling occurs in a multilayer film or sandwich film of Fe / Cr, Fe / Cu, Co / Cr, Co / Ru, or the like. Patent Document 2 describes a magnetic multilayer film in which soft magnetic films are laminated in multiple layers, and a magnetic head using this for a magnetic pole or a yoke portion. Patent Document 3 describes a spin valve sensor using an antiferromagnetic coupling film.

JP-A-2-61572 JP-A-7-135111 Japanese Unexamined Patent Publication No. 7-69026 JP-A-2-61572 Journal of Magnetics and Magnetic Materials, 93, (1991), 58-66 (J. Magn. Mag. Matt., 93, pp 58-66 (1991))

With the conventional technology, a magnetic recording device with a sufficiently high recording density, in particular, a submicron magnetic recording, and a magnetic head with sufficient characteristics to reproduce it accurately cannot be obtained, and the function as a storage device can be obtained. It was difficult to realize. The reason is the characteristics of the soft magnetic film and its demagnetizing field. A so-called soft magnetic thin film having a high magnetic permeability has been indispensable in order to perform magnetic operation at a high frequency and sufficient sensitivity and stability.

However, in recent years when the recording density of magnetic recording is greatly improved and the recording bit is becoming submicron, stable operation of the soft magnetic thin film is becoming difficult. This is because, in a soft magnetic film in which a smaller magnetic circuit is produced, a magnetic domain structure is formed at the end portion by the demagnetizing field of the soft magnetic film itself, which affects the characteristics of magnetic recording. In particular, the perpendicular recording type thin film magnetic head has a problem in that the residual magnetization generated in the magnetic pole erases or disturbs the magnetization information recorded on the recording medium because the magnetic pole has a magnetic domain structure after performing the recording operation. .

Conventionally, as a method for reducing the influence of such a demagnetizing field, a technique in which a soft magnetic film is multilayered with a nonmagnetic film and a single magnetic domain is formed by magnetostatic coupling at the end is known. The formation of a single magnetic domain by means of the coupling due to the static magnetic field coupling at the end results in a weak coupling force, and a sufficient effect is not obtained.

In recent years, in a multilayer film in which a ferromagnetic metal layer is stacked via a nonmagnetic metal layer, a phenomenon has been found in which the ferromagnetic film is antiferromagnetically coupled via the nonmagnetic metal layer. Here, “antiferromagnetically coupled” means that a coupling force is generated through the nonmagnetic metal layer so that the magnetizations of adjacent ferromagnetic layers are antiparallel to each other. Hereinafter, a magnetic sensor or the like has been proposed as represented by Patent Document 4 by applying this phenomenon.

The physical cause of the phenomenon in which the magnetizations of the multilayer film are coupled antiparallel to each other is not so clear, but is known to occur experimentally with a specific material and thickness. For example, Non-Patent Document 1 describes that antiparallel coupling occurs in a multilayer film or sandwich film of Fe / Cr, Fe / Cu, Co / Cr, Co / Ru, or the like.

More specifically, the size of the anti-parallel coupling increases or decreases as if it vibrates according to the thickness of the non-magnetic film, for example, Cr, and the thickness of the non-magnetic layer such as Cr is 1
It is known that antiparallel coupling occurs stably around nanometers and around 2 to 3 nanometers. As a proposal for applying such a phenomenon to a magnetoresistive sensor, Patent Document 3 describes a spin valve sensor using an antiferromagnetic coupling film.

In the present invention, in order to provide a magnetic head corresponding to a high recording density, a soft magnetic film used in the magnetic head, particularly a soft magnetic ferromagnetic multilayer film in which the main magnetic poles of a perpendicular recording head are antiferromagnetically coupled. Form with.

That is, in a magnetic head comprising a thin film magnetic head for perpendicular magnetic recording comprising a main magnetic pole having a tip for facing the magnetic recording medium and a coil for exciting the main magnetic pole, the tip or at least part of the main pole is A soft magnetic multilayer film including a laminate having a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film The main feature is that the antiparallel coupling layer has an antiferromagnetic interlayer coupling between the first ferromagnetic film and the second ferromagnetic film.

In order to realize an antiferromagnetically coupled soft magnetic multilayer film, the multilayer film has a minimum unit of ferromagnetic film / antiparallel coupling film / ferromagnetic film, and includes a ferromagnetic film and an antiparallel coupling film. It is formed flat with a predetermined material and thickness.

Further, it may be formed of a soft magnetic multilayer film in which the auxiliary magnetic pole and the magnetic shield are antiferromagnetically coupled.

As described above in detail, according to the present invention, a magnetic head having a stabilized magnetization state can be obtained. In particular, a magnetic head in which erasure after recording is suppressed in a perpendicular magnetic recording head can be obtained.

As a magnetic head to which the present invention is applied, for example, in a magnetic head comprising a thin film magnetic head for perpendicular magnetic recording comprising a main magnetic pole having a tip for facing a magnetic recording medium and a coil for exciting the main magnetic pole. A stack having at least a part of the first ferromagnetic film, the second ferromagnetic film, and the antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film. The antiparallel coupling layer is characterized in that the first ferromagnetic film and the second ferromagnetic film are antiferromagnetically interlayer-coupled.

The materials for the ferromagnetic film and the antiparallel coupling film are determined by a predetermined combination. When the ferromagnetic film has a body-centered cubic structure, the antiparallel coupling film is preferably composed mainly of Cr and Ru. The same effect can be obtained by using Os, Ir, Re, Rh instead of Ru. As appropriate, other elements such as Fe may be added to Cr, Ru, etc. to reduce the antiferromagnetic binding force, but the addition amount of other elements is preferably 20 atomic% or less.

When the ferromagnetic film has a face-centered cubic structure, it is desirable that the antiparallel coupling film is mainly composed of Ru. Similar effects can be obtained by using Os, Ir, Re, Rh, and Cu instead of Ru. As appropriate, other elements such as Fe may be added to Ru or the like to reduce the antiferromagnetic binding force, but the addition amount of other elements is preferably 20 atomic% or less.

In either case, the thickness of the antiparallel coupling film is 0.5-1.2 nanometers, or 1.8
When it is set to ~ 3 nanometers, a stable antiferromagnetic binding force can be obtained.

The antiferromagnetically coupled soft magnetic multilayer film has a flat structure with reduced unevenness,
The so-called orange peel effect that prevents antiferromagnetic coupling is prevented from occurring. For this purpose, in addition to optimizing the fabrication conditions of the soft magnetic multilayer film, the thickness of the ferromagnetic film is not excessively increased, specifically, 1 micron or less. Furthermore, a base such as NiCr may be formed on the base portion of about 5 nanometers so that the crystal grains of the soft magnetic multilayer film do not become too coarse.

When the ferromagnetic multilayer film of the present invention is used for a perpendicular recording magnetic head, the magnetization of the magnetic pole needs to be easily reversed with respect to the external magnetic field. Therefore, it is necessary that the antiferromagnetic interlayer coupling of the ferromagnetic multilayer film has an appropriate value. Specifically, the material and thickness of the ferromagnetic film and the antiparallel coupling film are appropriately combined. Furthermore, the thickness of the ferromagnetic multilayer film is 10 nanometers or more, and the amount of other elements added to the antiparallel coupling film is 20
Atomic% or less. With such a configuration, the antiferromagnetic coupling force of the soft magnetic multilayer film can be made several tens to several hundreds Oersted, and a magnetic head having a high magnetic permeability and a stable operation can be realized.

Hereinafter, a magnetic head to which the present invention is applied will be described in detail with reference to the drawings.

The thin film which comprises the soft-magnetic laminated film of this invention was produced as follows with the high frequency magnetron sputtering apparatus.

The following materials were sequentially laminated on a ceramic substrate in an argon atmosphere of 1 to 6 mTorr. As sputtering targets, nickel-20at% Cr alloy, copper, iron-30at% cobalt, chromium and ruthenium targets were used. A Fe-Co-Ni film was prepared by appropriately placing a 1 cm square chip of Ni or the like on the iron-cobalt target. In the laminated film, high frequency power was applied to each cathode on which each target was placed to generate plasma in the apparatus, and each layer was sequentially formed by opening and closing the shutters placed on each cathode one by one. In some film formations, a chromium target and an iron-cobalt target were simultaneously discharged and cosputtered to form an alloy layer of chromium and iron-cobalt.

6.4 kA / m (80 oersted) parallel to the substrate using permanent magnets when forming the film
A uniaxial anisotropy was imparted by applying a magnetic field of. Element formation on the substrate was patterned by a photoresist process. Thereafter, the substrate was processed with a slider and mounted on a magnetic recording apparatus. Specific examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration example of a soft magnetic laminated film used in the magnetic head of the present invention. The antiferromagnetically coupled soft magnetic laminated film 10 includes a base film 14, a ferromagnetic film (first ferromagnetic film) 15, an antiparallel coupling film 153, and a ferromagnetic film (second ferromagnetic film) 15 on a substrate 50. In the following, it is repeated and sequentially laminated. Adjacent ferromagnetic film 15 via antiparallel coupling film 153
Adjusts the material, thickness, and fabrication method of the antiparallel coupling film so that an antiferromagnetic coupling force that makes the magnetizations of each other antiparallel will work. The specific configuration will be described later.

By using the antiferromagnetically laminated film as described above, an antiparallel magnetic domain state can be stably achieved. For example, when the magnetic domain state is observed from the air bearing surface of the magnetic head with a spin SEM or a magnetic force microscope (MFM), it can be confirmed that the magnetic domain is antiparallel and closed. Even in a multilayer film that is simply multi-layered, a closed magnetic circuit state can be partially taken, but according to the present invention, a closed magnetic circuit state can be stably realized.

FIG. 2 shows the magnetic characteristics of the soft magnetic laminated film used in the present invention in comparison with a normal soft magnetic film. FIG. 2a) is an easy axis magnetization curve of the soft magnetic laminated film used in the present invention. An FeCo film is used as a ferromagnetic film, and two layers of FeCo films are antiferromagnetically coupled through an antiparallel coupling film of Cr 1 nm. The magnetization curve is stretched to the positive and negative regions of the magnetic field as if they were separated into two loops by the antiferromagnetic coupling force that the two layers of FeCo film try to arrange antiparallel to each other. You can see that

The increase in the saturation magnetic field seen in this magnetization curve is not a physical quantity intrinsic to the ferromagnetic film itself like the anisotropic magnetic field due to so-called uniaxial anisotropy, but the ferromagnetic film and the antiparallel coupling film,
And separate values depending on the thickness and structure of both. In order to accurately evaluate the antiferromagnetic coupling, integration of the magnetization curve should be performed. Here, as shown in FIG. 2a), a straight line approximating the magnetization curve is drawn and the saturation magnetic field is calculated. It will be treated as a saturation magnetic field Hs *.

If this is the case, this saturation magnetic field Hs * is a value that roughly describes the magnetization curve of the soft magnetic multilayer film used in the present invention. For example, when the saturation magnetic flux density Bs (unit: Tesla) is used, the saturation magnetic field Hs This is because the effective magnetic permeability of the soft magnetic laminated film which is * (Oersted) is approximately indicated by “magnetic permeability˜Bs × 10000 / Hs *”.

On the other hand, for comparison, the magnetization curve of the FeCo single layer film not using the antiparallel coupling film is shown in FIG. Unlike the case of FIG. 2a), a large saturation magnetic field or the like is not recognized in the magnetization curve. This is because even if an anisotropic magnetic field due to uniaxial anisotropy is observed in a single layer film, the magnitude is generally about 20 Oersted or less.

Whether or not antiferromagnetic coupling is generated using an antiparallel coupling film can be known from the shape of the magnetization curve as shown in FIG. 2, but if the magnetization curve cannot be measured, it is identified from the structure. You can also do it. A configuration for obtaining an appropriate antiparallel coupling will be described below.

FIG. 3 shows the magnetization curve of the FeCo / Cr / FeCo film when the Cr film thickness is changed. Cr film thickness
When changing from 0.9 to 1.1 nm, the magnetization curve changes greatly. C
It can be seen that the magnetization curve with r of 0.9 nm has a large remanent magnetization component and the antiparallel coupling is not uniform. As Cr increases from 0.95 to 1, the remanent magnetization component becomes almost zero and Hs * increases. Furthermore, as Cr becomes thicker, Hs * decreases.

FIG. 4 shows the relationship between the Cr and FeCoNi film thickness, the remanent magnetization ratio, and the saturation magnetic field Hs *. FIG. 4a) shows the results when the Cr film thickness is changed. When used as an antiparallel coupling layer, Cr has a thickness of 0.95 to 1.1 nm, particularly 1.0 nm.

Similarly, the result of the FeCoNi / Cr / FeCoNi film when the thickness of the FeCoNi film is changed is shown in FIG. When the FeCoNi film is as thin as 10 nm, Hs * is as large as 300 Oersteds, but as the FeCo film becomes thicker, Hs * decreases. The remanent magnetization is small and the antiparallel coupling state is obtained until the FeCoNi film is up to 30 nm, but the Hs * is almost zero when the FeCoNi film is 40 nm or more.
The remanent magnetization ratio is approximately 1, that is, no antiparallel coupling is achieved.

Originally, the energy of antiparallel coupling is determined by the combination and structure of the ferromagnetic film and antiparallel coupling film. Here, two factors are working. One is that if the anti-parallel coupling energy is constant as the thickness of the ferromagnetic film increases, the magnetic field of the anti-parallel coupling decreases in inverse proportion. This is because the energy of antiparallel coupling is the product of the amount of magnetization of the ferromagnetic film = saturation magnetic flux density × film thickness and the saturation magnetic field.

Another factor is that when the thickness of the laminated film increases, the unevenness of the laminated film increases, and a magnetostatic coupling called the so-called orange peel effect occurs between adjacent ferromagnetic films, which is antiparallel coupling. The effect of canceling out occurs. Such unevenness can be alleviated to some extent by optimizing the production conditions of the laminated film, but in our experiment, the thickness of the ferromagnetic film is 40-60 nm or more, and the total thickness of the laminated film is 0.1 When the thickness was 0.2 μm or more, anti-parallel bonds disappeared.

FIG. 5 shows magnetization curves of the FeCo / Cr / FeCo film and the FeCo / Ru / FeCo film. The thickness of the FeCo film was 10 nm, the thickness of Cr was 1.0 nm, and the thickness of Ru was 0.8 nm. When Cr is used, H
s * is about 300 Oersted, and in the case of Ru it is about 600 Oersted,
As a result, it was found that an antiparallel coupling force of about twice that obtained when Cr was used was obtained.

FIG. 6 shows the relationship of antiparallel bond energy when the thickness of the Ru film is changed. Anti-parallel coupling is obtained when the Ru film is between 0.6 and 1.0 nm, but the Ru film is between 0.7 and 0.9 nm, especially 0.
The best characteristics were obtained at 8 nm. In addition, a weak binding force was observed even when the thickness of the Ru film was around 2 nm. As can be seen, the thickness of the antiparallel coupling film is also a factor that changes the magnitude of the saturation magnetic field, but the thickness of the antiparallel coupling film is shown in FIGS.
As described above, it is very sensitive to the thickness. Therefore, in actuality, it is desirable that the thickness of the antiparallel coupling film is a peak thickness at which the coupling becomes large and stable. Therefore, it can be seen that the thickness is defined by the type of antiparallel coupling film.

FIG. 7 shows the relationship between the antiparallel coupling force of the NiFe / Cr / NiFe film and the Cr film thickness. Similar to the FeCoNi / Cr / FeCoNi film, the Cr film has a maximum antiparallel coupling force at 1 nm, except that the saturation magnetic field is 20 Oersted. As described above, the magnitude of the antiparallel coupling varies greatly depending on the type and thickness of the ferromagnetic film and the antiparallel coupling film, and the magnitude of the saturation magnetic field changes. Therefore, in order to obtain an antiparallel coupled soft magnetic laminated film having desirable characteristics, it is necessary to combine these structures with characteristics.

FIG. 8 shows the relationship between the saturation magnetic field and the amount of magnetization of the ferromagnetic film when the ferromagnetic film and the antiparallel coupling film are combined. The amount of magnetization of the ferromagnetic film is represented by the product of the thickness of the ferromagnetic film and the saturation magnetic flux density.

The saturation magnetic field decreases with the thickness of the ferromagnetic film, but the value differs depending on the type of the ferromagnetic film and the type of the antiparallel coupling film. Therefore, in order to obtain a soft magnetic laminated film in which the saturation magnetic field is appropriately set, it is necessary to appropriately select the types of the ferromagnetic film and the antiparallel coupling film and the thickness of the ferromagnetic film.

FIG. 8 shows experimental values of combinations of ferromagnetic films and antiparallel coupling films, and values of saturation magnetic fields expected from these values. On the other hand, the optimum value of the saturation magnetic field can be determined from the viewpoint of soft magnetism. As already mentioned, the permeability of the soft magnetic film is simply 10
000 x saturation magnetic flux density (Tesla) / saturation magnetic field (Oersted)
The saturation magnetic flux density of the ferromagnetic film is 2.4 T at maximum for the FeCo film and 1 T for the NiFe film, so it is not a factor that differs greatly from the others.

If the lower limit of the required magnetic permeability is 50, it will be the lower limit as a soft magnetic thin film. Similarly, the lower limit of the saturation magnetic field is considered to be 20 Oersted. This is because the CoNiFe alloy thin film has an anisotropy field of about 20 Oersteds, and if the saturation field is smaller than this, the anisotropy field becomes dominant and antiparallel coupling may not be realized.

Assuming that the saturation magnetic flux density is 2 T, the upper and lower limits of the saturation magnetic field can be defined from the above relationship, and it is understood that the saturation magnetic field is desirably 400 or less. That is, when the saturation magnetic field is 400 or more, even if the saturation magnetic flux density is 2 T, the magnetic permeability is substantially 50 or less, so that the function of the soft magnetic film is not performed. Further, as shown in FIG. 4b), when the ferromagnetic film is thicker than 50 nm, the remanent magnetization component increases, which also does not function as a soft magnetic film.

Conversely, when the thickness of the soft magnetic film is 5 nm or less, the volume as the soft magnetic film is insufficient, and the function as a magnetic flux conductor cannot be fulfilled sufficiently. This can be covered to some extent by laminating a large number of ferromagnetic films with a thickness of 5 nm or less, but in that case, the number of antiparallel coupling films is also increased to reduce the overall magnetic flux density, and many times The cost of doing so also increases.

Therefore, in order to satisfy the above conditions, the soft magnetic laminated film used in the present invention has a thick square portion in FIG. 8, that is, a saturation magnetic field of 20 or more and 400 or less, and a ferromagnetic film thickness of 5 nm to 50 nm. It is desirable to use nm.

Furthermore, the conditions satisfying the above specified range are limited depending on the type of antiparallel coupling film. When the ferromagnetic film is an FeCoNi film and the antiparallel coupling film is Cr (1 nm), the thickness of the ferromagnetic film satisfies the specified range at about 20 nm to 50 nm.

On the other hand, when the ferromagnetic film is CoFe and the antiparallel coupling film is Ru (0.8 nm), there is no region that satisfies the specified range even if the thickness of the ferromagnetic film is changed. Table 1 summarizes the combinations that satisfy the above specified range. The table also shows the saturation magnetic flux density Bs and crystal structure of the ferromagnetic film. This is because even if the composition of the ferromagnetic film and the additive element are slightly changed, the characteristics are almost the same as long as Bs and the crystal structure are not largely changed.

On the other hand, the antiferromagnetic coupling force can be slightly controlled by adding other elements to the antiparallel coupling film. FIG. 9 shows FeCo 25 in which Fe—Co is added to Cr as an antiparallel coupling film.
It is a magnetization curve of a nm / Cr- (Fe, Co) 1 nm / FeCo 25 nm film. When the addition amount is zero, the saturation magnetic field is about 200 oersteds, but it can be seen that when Fe—Co is added to Cr, the magnetization curve gradually decreases. When the Fe-Co addition amount is 20 at%,
Antiferromagnetic coupling results in a magnetization curve that is hardly recognized, and the residual magnetization is increased.

FIG. 10 shows the relationship between the amount of Fe—Co added to Cr and the saturation magnetic field and remanent magnetization ratio of the FeCo 25 nm / Cr— (Fe, Co) 1 nm / FeCo 25 nm film. It can be seen that the saturation magnetic field decreases with the addition amount, and can be controlled up to about half of the case where the addition amount is zero. However, in the region where the added amount increases and the saturation magnetic field is considerably smaller than the initial value, the degree of decrease with respect to the added amount of the saturated magnetic field is large, and the residual magnetization ratio increases, so there is a risk that appropriate characteristics cannot be obtained. is there. Therefore, it was found from the results of FIG. 10 that the appropriate addition amount is 20 at% or less, and the saturation magnetic field can be reduced to about half of the case without addition.

Further, the base film of the soft magnetic laminated film used in the present invention will be described. In FIG. 1, a base film 14 is disposed on the soft magnetic laminated film of the present invention. Figure 11 shows NiCr as the underlayer.
Magnetization curves with and without the film are shown. As described in FIG. 2, the magnetization curve of the soft magnetic multilayer film using the base film is a magnetization curve that clearly reflects the antiferromagnetic coupling, but the magnetization curve without the base film is maintained. Magnetic force increases,
Antiferromagnetic coupling is less clear. This is because the coercive force is large enough to be comparable to the saturation magnetic field. Even if there is some antiferromagnetic coupling, a remanent magnetization component is generated due to the coercive force, and sufficient soft magnetic characteristics can be obtained. Absent. Therefore, it is desirable to use an appropriate underlayer such as NiCr. In addition to the NiCr film, Ti, Cr
The same effect can be obtained to some extent with Ru and the like.

An example of a magnetic head using the above-described soft magnetic laminated film antiparallel coupled is shown below. FIG. 12 is a structural example of a perpendicular recording magnetic head using the antiferromagnetically coupled soft magnetic laminated film of the present invention as the main pole. A lower magnetic shield 35, an electrode 40, and a magnetoresistive layered film 101 are formed on a substrate 50 that also serves as a slider, and further, an electrode 40 and an upper magnetic shield 36 are formed to reproduce a reproduction gap 43 for detecting a reproduction signal.
Formed. Here, current is applied in the film thickness direction as the reproducing part, TMR or C
Although a PP-GMR type regeneration sensor is illustrated, other regeneration sensors such as a GMR regeneration sensor that flows current in the in-plane direction do not detract from the gist of the present invention.

The recording head portion further includes a magnetic path formed by the sub magnetic pole 84, the coil 42, and the main magnetic pole 83. In FIG. 12, the main magnetic pole 83 is formed of the antiparallel coupled soft magnetic laminated film 10.
That is, the ferromagnetic film 15, the antiparallel coupling film 153, and the ferromagnetic film 15 are sequentially stacked on the base film 14. The ferromagnetic film 15 may be about 4 to 12 layers in the entire main pole,
If the number of stacked layers is small, there is a concern that the magnetic poles cancel each other out at the end, and if the number of stacked layers is too large, the recording ability decreases, so 6 to 8 layers are particularly desirable. The number of layers of the ferromagnetic film is desirably an even number so that the magnetizations of the ferromagnetic films arranged in antiparallel cancel each other out. The magnetic head forms a facing surface 63 and records and reproduces magnetic recording in the vicinity of the magnetic recording medium.

FIG. 13 shows another configuration example of the magnetic head for perpendicular recording using the antiferromagnetically coupled soft magnetic laminated film of the present invention as the main magnetic pole. A lower magnetic shield 35, an electrode 40, and a magnetoresistive layered film 101 are formed on a substrate 50 that also serves as a slider, and further, an electrode 40 and an upper magnetic shield 36 are formed to form a reproduction gap 43 for detecting a reproduction signal. Do it. Here, a TMR or CPP-GMR type reproduction sensor that applies current in the film thickness direction as the reproduction unit is illustrated, but other reproduction sensors such as a GMR reproduction sensor that flows current in the in-plane direction may be used. The gist of the present invention is not impaired.

The recording head portion further includes a magnetic path formed by the sub magnetic pole 84, the coil 42, the first main magnetic pole 831, and the second main magnetic pole 832. In FIG. 14, the first main magnetic pole 831 is formed of the antiparallel coupled soft magnetic laminated film 10. That is, the ferromagnetic film 15, the antiparallel coupling film 153, and the ferromagnetic film 15 are sequentially stacked on the base film 14. The ferromagnetic film 15 is preferably about 4 to 12 layers in the entire main magnetic pole. However, if the number of stacked layers is small, there is a concern that the magnetic poles cancel each other at the end, and if the number of stacked layers is too large, the recording ability is high. In particular, 6 to 8 layers are desirable because of lowering. The number of layers of the ferromagnetic film is desirably an even number so that the magnetizations of the ferromagnetic films arranged in antiparallel cancel each other out. Magnetic head is facing surface 6
3 is formed, and magnetic recording is recorded and reproduced close to the magnetic recording medium.

FIG. 14 shows a configuration example of a magnetic recording / reproducing apparatus using the magnetic head of the present invention. A disk 95 holding a recording medium 91 for magnetically recording information is rotated by a spindle motor 93, and a head slider 90 is guided onto a track of the disk 95 by an actuator 92. That is, in the magnetic disk apparatus, the reproducing head formed on the head slider 90 and the recording head move relative to a predetermined recording position on the disk 95 by this mechanism and sequentially write and read signals. .

The actuator 92 is preferably a rotary actuator.
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 onto a desired recording track, the position on the track can be detected using a highly sensitive output from the reproducing head, and the actuator can be controlled to position the head slider. In this figure, the head slider 90 and the disk 95 are shown.
One of each is shown, but there may be a plurality of these. The disk 95 may have a recording medium 91 on both sides to record information. When information is recorded on both sides of the disc, the head slider 90 is arranged on both sides of the disc.

FIG. 15 is a diagram showing the incidence of defects due to post-recording erasure, measured using a perpendicular recording magnetic head using the antiferromagnetically coupled soft magnetic multilayer film of the present invention as the main pole. In FIG. 15 a), the magnetic film thickness is changed from 0.5 nm to 5 nm of Cr, which should be an antiparallel coupling layer, and the antiferromagnetic coupling force is changed and eliminated, and the Cr film thickness is 0
A magnetic head using nm, that is, a single-layer main magnetic pole was manufactured and measured.

With a magnetic head with a single-layer main pole, the defect rate is almost 100%, and this makes it impossible to achieve magnetic recording. For heads with a Cr film thickness of 0.5 nm to 1.3 nm, the defect rate decreased to 50% or less, and in particular for heads with a Cr film thickness of 1 nm, it decreased to 25% or less. This indicates that the use of a soft magnetic film having antiferromagnetic coupling as the main magnetic pole has a remarkable effect in suppressing erasure after recording. Furthermore, the defect rate tends to increase as the Cr film thickness is increased to 1.3 nm or more. The main pole magnetic head with a multilayer film with a thickness of 2 nm or more that does not cause antiferromagnetic coupling with a Cr film thickness of 2 nm or more has a defect rate of about 80% and has a slight effect on improving the defect rate, but it is normal. It can be seen that recording is not possible.

In FIG. 15b), the total film thickness of the magnetic film (FeCoNi) in the entire laminated film is constant at 200 nm, a head is manufactured with the FeCoNi film thickness and the number of layers per layer being changed, and the defect occurrence rate is measured. Show. That is, when the thickness per FeCoNi film is 25 nm, eight layers are stacked, and when the thickness is 33 nm, six layers are stacked. At this time, the Cr film thickness was set to 1 nm so as to maximize the antiferromagnetic coupling. Even if the FeCoNi film thickness is increased to around 40 nm, the defect rate is 25% or less for all heads.
It can be seen that when the thickness is greater than 0 nm, the defect rate is close to 100%. That is, the thickness of the magnetic layer per layer needs to be 50 nm or less.

On the other hand, as shown in FIG. 4b), the result that the saturation magnetic field tends to increase as the magnetic layer becomes thinner is obtained, so that the overwrite is reduced when applied to the head. There are concerns. In FIG. 15b), sufficient overwriting characteristics are obtained even when the FeCoNi film thickness is 10 nm. When the above results are combined, the magnetic film thickness in the multilayer main pole having antiferromagnetic coupling is 10 nm to 50 nm. It is good to do.

FIG. 16 is a conceptual diagram of the effect of the present invention. When the main magnetic pole of the perpendicular magnetic recording head is a single-layer ferromagnetic film, the magnetization of the main magnetic pole after the recording operation becomes a magnetic domain state having a component toward the magnetic recording medium, as shown in FIG. It can be considered that the magnetization state in which the magnetization of is present causes erroneous recording.

It is conceivable to divide the main pole into multiple layers of ferromagnetic film so that the magnetizations can be antiparallel to each other as shown in FIG. 16b), and to reduce the penetration of magnetic flux into the recording medium. In this case, an antiparallel arrangement of the magnetized state must be realized only by the demagnetizing field at the main magnetic pole end. In perpendicular magnetic recording, since a soft magnetic film is disposed as the backing layer of the recording medium, the magnetic flux at the end of the main pole can be transmitted to the backing layer (FIG. 16c). It is difficult to realize a desired closed magnetization state only.

The magnetic head using the antiferromagnetically coupled soft magnetic film of the present invention has a magnetic characteristic for realizing antiparallel magnetization in the soft magnetic laminated film, that is, an antiferromagnetic magnetic coupling. As shown in 16d), a desired magnetization state can be stably realized in the main magnetic pole of the perpendicular magnetic recording head. In this case, between the ferromagnetic films of the laminated film,
In addition to the magnetostatic coupling at the end of the main pole, there is antiferromagnetic coupling energy, which has the effect of not realizing the magnetic domain state in which erasure after recording occurs as shown in FIG.

As described above, the antiferromagnetically coupled soft magnetic film used in the present invention has an effect of stably realizing a magnetization state in which magnetizations are arranged in antiparallel to each other, and therefore has a patterned end portion. This has the effect of preventing the occurrence of an undesirable magnetic domain state due to the demagnetizing field often found in magnetic films. This effect can be applied to other than the main magnetic pole of the perpendicular magnetic recording head.

FIG. 17 shows a configuration example of a perpendicular magnetic recording head using the antiferromagnetically coupled soft magnetic film of the present invention as a sub magnetic pole. A lower magnetic shield 35, an electrode 40, and a magnetoresistive layered film 101 are formed on a substrate 50 that also serves as a slider.
The upper magnetic shield 36 is formed, and a reproduction gap 43 for detecting a reproduction signal is formed. TMR or CPP-G where current is applied in the film thickness direction as the playback section
Although an MR type reproduction sensor is illustrated, other types of reproduction sensors such as a GMR reproduction sensor that flows current in the in-plane direction do not impair the gist of the present invention.

The recording head portion further includes a magnetic path formed by the sub magnetic pole 84, the coil 42, and the main magnetic pole 83. In FIG. 17, the sub magnetic pole 84 is formed of the antiparallel coupled soft magnetic laminated film 10.
That is, the ferromagnetic film 15 and the antiparallel coupling film 153 are sequentially stacked. The ferromagnetic film 15 may be about 2 to 12 layers in the entire sub magnetic pole. The number of layers of the ferromagnetic film is desirably an even number so that the magnetizations of the ferromagnetic films arranged in antiparallel cancel each other out. The magnetic head forms a facing surface 63 and records and reproduces magnetic recording in the vicinity of the magnetic recording medium.

FIG. 18 is a structural example of a perpendicular magnetic recording head using the antiferromagnetically coupled soft magnetic film of the present invention as a magnetic shield. A lower magnetic shield 35, an electrode 40, and a magnetoresistive layered film 101 are formed on a substrate 50 that also serves as a slider, and an electrode 40 and an upper magnetic shield 36 are further formed to detect a reproduction signal 4.
3 is formed.

Here, a TMR or CPP-GMR type reproduction sensor that applies current in the film thickness direction as the reproduction unit is illustrated, but other reproduction sensors such as a GMR reproduction sensor that flows current in the in-plane direction may be used. The gist of the present invention is not impaired. The recording head portion further includes a magnetic path formed by the sub magnetic pole 84, the coil 42, and the main magnetic pole 83.

In FIG. 18, the lower magnetic shield 35 and the upper magnetic shield 36 are formed of the antiparallel coupled soft magnetic laminated film 10. That is, the ferromagnetic film 15 and the antiparallel coupling film 153
Are sequentially laminated. The ferromagnetic film 15 is formed on the entire upper or lower magnetic shield.
It is good to have about 2 to 12 layers. Either the top shield or the bottom shield,
Or it is not contrary to the main point of this invention even if it uses for only those one part.

The number of layers of the ferromagnetic film is desirably an even number so that the magnetizations of the ferromagnetic films arranged in antiparallel cancel each other out. The magnetic head forms a facing surface 63 and records and reproduces magnetic recording in the vicinity of the magnetic recording medium. If the magnetic shield is composed of a soft magnetic laminated film antiferromagnetically coupled in this way, fluctuations in the output of the read head due to the magnetic shield can be reduced.

FIG. 19 shows a configuration example of an in-plane magnetic recording head using the antiferromagnetically coupled soft magnetic film of the present invention at the tip of the upper magnetic core. A lower magnetic shield 35, an electrode 40, and a magnetoresistive layered film 101 are formed on a substrate 50 that also serves as a slider, and further, an electrode 40 and an upper magnetic shield 36 are formed to form a reproduction gap 43 for detecting a reproduction signal. Do it.

Here, a TMR or CPP-GMR type reproduction sensor that applies current in the film thickness direction as the reproduction unit is illustrated, but other reproduction sensors such as a GMR reproduction sensor that flows current in the in-plane direction may be used. The gist of the present invention is not impaired. The recording head unit further includes a magnetic path formed by the lower magnetic core 85, the coil 42, the first upper magnetic core 833, and the second upper magnetic core 834.

Here, the upper magnetic core is shown as being composed of the first and second upper magnetic cores. However, even if the upper magnetic core is composed of one unit or three or more units, it is not contrary to the gist of the present invention. Absent. Thus, when the magnetic core is made of a soft magnetic laminated film antiferromagnetically coupled, the magnetic domain state at the end is stabilized, and there is an effect of reducing post-recording noise and improving the shape of the end of the recording magnetic field.

In FIG. 19, the first upper magnetic core 833 is formed of the antiparallel coupled soft magnetic laminated film 10. That is, the ferromagnetic film 15 and the antiparallel coupling film 153 are sequentially stacked.
The entire upper or lower magnetic core may have about 2 to 12 ferromagnetic films 15.
Although it is not contrary to the gist of the present invention even if it is used for either the upper magnetic core, the lower magnetic core, or only a part thereof, it is preferable to use it for the tip of the upper magnetic core. The number of layers of the ferromagnetic film is desirably an even number so that the magnetizations of the ferromagnetic films arranged in antiparallel cancel each other out. The magnetic head forms a facing surface 63 and records and reproduces magnetic recording in the vicinity of the magnetic recording medium.

FIG. 20 shows another configuration example of the soft magnetic laminated film used in the magnetic head of the present invention.
The antiferromagnetically-coupled soft magnetic multilayer film 10 is formed by sequentially and successively laminating a base film 14, a ferromagnetic film 15, an antiparallel coupling film 153, a ferromagnetic film 15, a nonparallel coupling film 154. . The ferromagnetic film 15 adjacent via the antiparallel coupling film 153 has an antiparallel coupling film material, thickness, and manufacturing method so that an antiferromagnetic coupling force that makes the magnetizations antiparallel to each other works. adjust.

On the other hand, the non-parallel coupling film 154 is a film that separates the magnetizations of the adjacent ferromagnetic films 15 via the non-parallel coupling film 154 so as not to be coupled antiparallel to each other.
Or a thickness that does not cause antiferromagnetic coupling with the same material as the parallel coupling film 153. For example, the antiparallel coupling film 153 is Cr 1 nm and the non-parallel coupling film 154 is NiCr 1 nm, or the antiparallel coupling film 153 is Cr
For example, the configuration may be 1 nm, and the non-parallel coupling film 154 may be Cr 3 nm.

As shown in the configuration example of FIG. 20, each ferromagnetic film 15 has a parallel coupling film 15 at one interface.
3 is antiferromagnetically coupled to the adjacent ferromagnetic film 15 via 3, and the other interface is formed to be not antiferromagnetically coupled to the adjacent ferromagnetic film 15 via the non-parallel coupling film 154. Thus, it is possible to obtain a soft magnetic laminated film having a high permeability with a moderately reduced saturation magnetic field.

This is the structure shown in FIG. 1, in which each ferromagnetic film 15 is 2 except for a pair of upper and lower ends.
Since two interfaces are antiferromagnetically coupled to the adjacent ferromagnetic film 15 via the parallel coupling film 153, there are many contributing coupling interfaces and, as a result, a large saturation magnetic field can be obtained. In No. 20, the interface that couples antiferromagnetically can be halved, so that every other interface structure allows the saturation magnetic field to be adjusted lower. The soft magnetic laminated film of this configuration can also be applied to the various magnetic head portions described above, similarly to the configuration of FIG.

As a result of testing the magnetic head of the present invention and the magnetic recording / reproducing apparatus equipped with the magnetic head of the present invention as described above, it showed a sufficient output, good recording / reproducing characteristics, and good operation reliability.

It is an example of a structure of the soft-magnetic laminated film used for the magnetic head of this invention. It is the figure which showed the magnetic characteristic of the soft magnetic laminated film used for this invention compared with the normal soft magnetic film. It is a magnetization curve of the FeCo / Cr / FeCo film when the Cr film thickness is changed. FIG. 5 is a diagram showing the relationship between the residual magnetization ratio and the saturation magnetic field Hs * when the Cr film thickness and the FeCoNi film thickness are changed. It is a magnetization curve of a FeCo / Cr / FeCo film and a FeCo / Ru / FeCo film. It is the figure which showed the relationship of the antiparallel coupling energy at the time of changing the thickness of Ru film | membrane. FIG. 5 is a diagram showing the relationship between the antiparallel coupling force of a NiFe / Cr / NiFe film and the Cr film thickness. It is the figure which showed the relationship between the saturation magnetic field at the time of combining a ferromagnetic film and an antiparallel coupling film, and the magnetization amount of a ferromagnetic film. It is a magnetization curve of a FeCo 25 nm / Cr— (Fe, Co) 1 nm / FeCo 25 nm film in which Fe—Co is added to Cr as an antiparallel coupling film. FIG. 6 is a graph showing the relationship between the amount of Fe—Co added to Cr and the saturation magnetic field and remanent magnetization ratio of an FeCo 25 nm / Cr— (Fe, Co) 1 nm / FeCo 25 nm film. FIG. 6 is a diagram showing magnetization curves when a NiCr film is used as a base film and when there is no base film. 1 is a configuration example of a magnetic head for perpendicular recording using an antiferromagnetically coupled soft magnetic laminated film of the present invention as a main pole. 4 is another configuration example of a perpendicular recording magnetic head using the antiferromagnetically coupled soft magnetic laminated film of the present invention as a main pole. 1 is a configuration example of a magnetic recording / reproducing apparatus using a magnetic head of the present invention. FIG. 5 is a diagram showing the incidence of defects due to post-recording erasure measured using a perpendicular recording magnetic head using the antiferromagnetically coupled soft magnetic laminated film of the present invention as a main pole. It is a conceptual diagram of the magnetization state of the main pole of the perpendicular magnetic recording head showing the effect and principle of the present invention. 1 is a configuration example of a perpendicular magnetic recording head using an antiferromagnetically coupled soft magnetic film of the present invention as a sub magnetic pole. 1 is a configuration example of a perpendicular magnetic recording head using an antiferromagnetically coupled soft magnetic film of the present invention as a magnetic shield. 2 is a configuration example of an in-plane magnetic recording head using an antiferromagnetically coupled soft magnetic film of the present invention at the tip of an upper magnetic core. It is another example of a structure of the soft-magnetic laminated film used for the magnetic head of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Antiferromagnetic coupling soft magnetic laminated film, 101 ... Magnetoresistance effect laminated film, 14 ... Underlayer film, 15 ... Ferromagnetic film, 153 ... Antiparallel coupling film, 154 ... Non-parallel coupling film, 35 ... Lower magnetic shield 36 ... Upper magnetic shield, 40 ... Electrode, 42 ... Coil, 43 ...
Reproduction gap, 50 ... base, 63 ... facing surface, 71 ... lower gap film, 72 ... upper gap film, 83 ... main magnetic pole, 831 ... first main magnetic pole, 832 ... second main magnetic pole, 8
33: First upper magnetic core, 834: Second upper magnetic core, 84: Sub magnetic pole, 90
... head slider, 91 ... recording medium, 92 ... actuator, 93 ... spindle, 94 ... signal processing system, 95 ... magnetic disk.

Claims (11)

In a magnetic head comprising a thin film magnetic head for perpendicular magnetic recording comprising a main magnetic pole having a tip for facing the magnetic recording medium and a coil for exciting the main magnetic pole,
The tip or at least part of the main magnetic pole is formed of a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film. A soft magnetic multilayer film containing a laminate having
2. The magnetic head according to claim 1, wherein the soft magnetic multilayer film is formed by laminating the laminated body via a non-parallel coupling film.   2. The magnetic head according to claim 1, wherein the first ferromagnetic film and the second ferromagnetic film contain at least one of Co, Ni, and Fe.   2. The magnetic head according to claim 1, wherein the antiparallel coupling layer contains at least one of Cr, Ru, Os, Re, Rh, or Cu.   2. The magnetic head according to claim 1, wherein the thickness of the antiparallel coupling layer is in the range of 0.5 nm to 1.2 nm.   2. The magnetic head according to claim 1, wherein the thickness of the antiparallel coupling layer is in the range of not less than 1.8 nm and not more than 3 nm.   2. The magnetism according to claim 1, wherein the magnetization direction in the first ferromagnetic layer and the magnetization direction in the second ferromagnetic layer are antiparallel with the antiparallel coupling layer interposed therebetween. head.   2. The magnetic head according to claim 1, wherein the magnitude of the antiferromagnetic interlayer coupling is equivalent to several tens to several hundreds Oersted.   The first ferromagnetic film and the second working magnetic film are formed by a vacuum thin film forming method, and are formed on a base film of about 5 nanometers made of NiCr or the like in the same vacuum forming process. 2. The magnetic head according to claim 1, wherein the flatness in the parallel coupling layer film portion is such that the flatness is small compared to the thickness of the antiparallel coupling layer.   The magnetic head according to claim 1, further comprising a reproducing head for detecting a magnetic field. In a thin film magnetic head for perpendicular magnetic recording, comprising: a main magnetic pole having a tip for facing a magnetic recording medium; a sub magnetic pole that forms a magnetic circuit with the main magnetic pole; and a coil that excites the main magnetic pole.
At least a part of the sub magnetic pole has a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film. A soft magnetic multilayer film containing a laminate,
2. The magnetic head according to claim 1, wherein the soft magnetic multilayer film is formed by laminating the laminated body via a non-parallel coupling film. In a magnetic head that detects a magnetic field leaking from a recording medium facing a magnetic recording medium on which information is magnetically recorded and magnetically records on the recording medium, a lower magnetic shield and a lower gap are formed on a substrate. A magnetic head in which a reproducing element portion, an upper gap, and an upper magnetic shield are formed, and the lower magnetic shield and the upper magnetic shield form a magnetic reproducing gap at a predetermined interval,
At least a part of the lower magnetic shield and the upper magnetic shield are antiparallel formed between the first ferromagnetic film, the second ferromagnetic film, and the first ferromagnetic film and the second ferromagnetic film. A soft magnetic multilayer film comprising a laminate having a bonding layer,
2. The magnetic head according to claim 1, wherein the soft magnetic multilayer film is formed by laminating the laminated body via a non-parallel coupling film.

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