JPH05298610A - Magnetic recording head and magnetic disk device - Google Patents

Abstract

PURPOSE:To provide the high-recording density magnetic disk device mounted with a recording/reproducing sepn. type magnetic head including a magnetic recording head using magnetic films having a high saturation magnetic flux density, low coercive force and excellent corrosion to a soln. to be used at the time of production, etc. CONSTITUTION:This high-recording density magnetic disk device is mounted with the recording/reproducing sepn. type magnetic head including the magnetic recording head 103 constituted by using the magnetic thin films consisting of 40 to 70at.% Co, 10 to 30at.% Ni, 15 to 40at.% Fe and 1 to 10at.% Cu for an upper magnetic core 112 and a lower magnetic core 113 and a reproducing head 115. The device has the high saturation magnetic flux density, the low coercive force and the good corrosion resistance and heat resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording head and a magnetic disk device, and more particularly to a magnetic core of a recording / reproducing separated type magnetic recording head for high recording density applications.

[0002]

2. Description of the Related Art In recent years, with the increase in recording density of magnetic disk devices, recording media have become high in coercive force. Magnetic recording having sufficient ability to record / reproduce information on / from this high coercive force recording medium. Head is required.

In response to this request, Japanese Patent Laid-Open No. 64-8605
No. proposes a Co-Ni-Fe ternary material.
Since the three-element material has a large anisotropic magnetic field Hk of 25 to 30 oersteds, it has a low magnetic permeability and a low reproducing efficiency, and is insufficient as a material for a recording / reproducing head. Further, since a large amount of Fe is contained, there is a problem that corrosion resistance is likely to be impaired and reliability in the head manufacturing process is lacking.

Under these circumstances, in order to achieve a high recording density, recently, a so-called recording / reproducing separated head, that is, a dual head in which recording and reproducing are independent, is becoming the mainstream, and high recording is achieved. It is desired to develop a recording-only magnetic head compatible with higher density.

[0005]

The performance required of the recording head is as follows. High saturation magnetic flux density and sufficient recording on high coercive force recording media b. The coercive force is small, the recording demagnetization is small, and the magnetoresistive reproducing head is not adversely affected. C. In particular, it has corrosion resistance and heat resistance and can withstand a head manufacturing process sufficiently.

[0006] As a material satisfying such requirements, Co
Various materials such as a system-based amorphous material and a Fe-Al-Si sendust-based thin film have been proposed. However, the amorphous material is essentially thermally unstable, and the Fe—Al—Si sendust thin film requires heat treatment at a high temperature of about 500 ° C. It is not compatible with the manufacturing process of thin film magnetic heads for disks. The above Co-Ni
One of them is the -Fe-based crystalline material, but the magnetic properties for a recording head are unknown, and it is also difficult to corrode the lapping liquid against acids and the like during polishing.

Further, JP-A-59-220907 discloses C
An alloy combining o-Ni-Fe with other elements is proposed. In this conventional example, when an element such as Ag is contained, the saturation magnetic flux density becomes low. Further, the coercive force after the heat treatment is large, which is not suitable for the magnetic recording head for the recording / reproducing separated type recording head targeted by the present invention.

Further, JP-A-1-283907 discloses C
It proposes a multilayer magnetic thin film in which a main magnetic film made of a component such as o and Fe, a first intermediate film made of a component such as Ag, and a second intermediate film made of a component such as B are laminated. In this conventional example, it is recognized that the control of the thickness of each film is delicate, and that the eddy current loss and the improvement of high frequency characteristics cannot be achieved at the same time unless a multilayer structure is used.

An object of the present invention is to provide a magnetic recording head for a recording / reproducing separated type recording head using a thin film magnetic material having both good magnetic properties and, in particular, corrosion resistance and heat resistance.

Another object of the present invention is to provide a magnetic disk device equipped with the magnetic recording head.

Another object of the present invention is to provide a thin film magnetic material for a magnetic recording head which has both good magnetic properties and, in particular, corrosion resistance and heat resistance.

[0012]

In order to achieve the above object, the present invention comprises a quaternary alloy of Co, Ni, Fe and Cu, and the composition range of each element is Co: 40 to 70 at.
%, Ni: 10 to 30 at%, Fe: 15 to 40 at
%, Cu: 1 to 10 at% A magnetic recording head using a magnetic thin film as a magnetic core is proposed. It is preferable that the crystal structure of the magnetic thin film is made of face-centered cubic crystal and the (111) plane is preferentially oriented.

In order to achieve the above other object, the present invention comprises at least one magnetic disk for recording information,
A recording / reproducing separated type magnetic head comprising means for rotating the magnetic disk, a magnetic recording head for writing information to the magnetic disk, and a magnetic reproducing head for reading information from the magnetic disk, and a target for supporting the recording / reproducing separated type magnetic head. The magnetic recording head comprises a quaternary alloy of Co, Ni, Fe and Cu, and the composition range of each element is Co: 40 to 70 at%, N
i: 10 to 30 at%, Fe: 15 to 40 at%, C
The present invention proposes a magnetic disk device in which a magnetic thin film having u: 1 to 10 at% is used as a magnetic core.

In order to achieve the above-mentioned another object, the present invention further comprises a quaternary alloy of Co, Ni, Fe and Cu, wherein the composition range of each element is Co: 40 to 70 at.
%, Ni: 10 to 30 at%, Fe: 15 to 40 at
%, Cu: 1-10 at%, a magnetic thin film for a magnetic recording head is proposed.

[0015]

The bulk material or the thin film magnetic material, which is well known as a material exhibiting a high saturation magnetic flux density, includes Fe-based and Fe-
There are a Co type, the above-mentioned Co-Ni-Fe type, and the like. When it is used as a magnetic core of a thin-film recording head for a magnetic disk, it has not been put to practical use because of restrictions on magnetic characteristics, such as reduction of magnetostriction constant, low coercive force, and process resistance such as corrosion resistance during manufacturing. Has not arrived.

[0016] FIG. 9 shows "c" of "Ferromagnetism" by Bozorth.
FIG. 5 is a diagram showing the relationship between the composition and magnetic properties of the bulk material and vapor-deposited thin film of a Co—Ni—Fe ternary alloy based on the description of hp. From this figure, the value of the saturation magnetic flux density or the magnetostriction constant can be analogized based on the composition, but the coercive force varies depending on the film forming conditions in addition to the composition, and therefore it is difficult to analogize. However, considering the value of permalloy, it is expected that the coercive force decreases as the Co and Fe contents decrease, that is, the Ni content increases. Therefore, increasing the saturation magnetic flux density and decreasing the coercive force are compositionally opposite.

Therefore, the composition range in which the magnetostriction constant has a large positive value but the saturation magnetic flux density is relatively high was selected, and the relationship between the composition and the magnetic characteristics was mainly investigated. The film was formed using a high frequency magnetron sputtering device.

FIG. 10 is a diagram showing the relationship between the composition of the magnetic thin film and the magnetic characteristics. From this figure, it can be seen that the saturation magnetic flux density almost corresponds to the literature values shown in FIG. On the other hand, the coercive force is considerably different depending on the Fe content, and it can be seen that the Fe content needs to be 15 wt% or more in order to reduce the coercive force. Combining these conditions,
A relatively small composition region having a relatively high saturation magnetic flux density and a coercive force of 3 Oersted or less is Co: 40-70.
at%, Ni: 10 to 30 at%, Fe: 15 to 40a
It was in the range of t%.

A typical composition is 51Co-26Ni-
A 23 Feat% film was formed, and a recording head was prototyped and its performance was evaluated. The magnetic characteristics of the film are that the saturation magnetic flux density is
The magnetic field was 1.7 tesla, the coercive force was 0.8 oersted, the anisotropic magnetic field was 27 oersted, and the magnetostriction constant was + 40 × 10 to ⁷ . Except that the anisotropic magnetic field is large and the magnetostriction constant is a large positive value, both the saturation magnetic flux density and the coercive force exhibit excellent characteristics, suggesting that the magnetic recording head is promising. Even if the anisotropic magnetic field is a little large,
Recording is sufficiently possible in consideration of the excitation ampere-turn.

On the other hand, the magnetostriction constant is determined by the balance with the stress of the film. Therefore, when the magnetostriction constant is assembled as a magnetic core of the magnetic recording head, the direction of magnetization with respect to the magnetic path direction of the magnetic head, rather than its absolute value. Depends on whether it is oriented at right angles. As a result of observing the magnetic domain structure by patterning the magnetic film of the present invention in the shape of a magnetic core, it was found that the direction of magnetization was perpendicular to the magnetic path direction, and it sufficiently followed even at high frequency drive. It was As described above, the material of the composition region of the present invention is magnetically excellent except for the corrosion resistance at the time of manufacture, and it is speculated that excellent recording characteristics can be obtained when used as the magnetic core of the magnetic recording head. ..

From the above consideration, the above composition range of the present invention is, of course, defined in order to secure the characteristics of high saturation magnetic flux density and low coercive force, but in particular, from the viewpoint of corrosion resistance during production. There is. That is, from the viewpoint of corrosion resistance during manufacturing, the main focus was on the selection of elements to be added to the Co—Ni—Fe ternary material so as to improve the corrosion resistance without impairing the magnetic properties. In the Co-Ni-Fe ternary element system, a composition range showing good magnetic characteristics as a magnetic recording head is selected, and based on this composition, an element for improving corrosion resistance at the time of manufacturing is selected within a range not impairing the magnetic characteristics. Was added. As the additional element, Cu having the same crystal structure as the face-centered cubic crystal of the Co—Ni—Fe ternary elemental basic composition and being solid-dissolved in the basic composition was selected and its composition range was examined. In addition, for comparative reference, Cr is known as an element forming a passivation film in stainless steel or the like.
We are considering the addition of.

In order to produce a magnetic film having such a composition range, it is common to use high-frequency magnetron sputtering in consideration of mass productivity, but other general sputtering such as DC sputtering and a facing target.・ Sputtering, ion beam sputtering, or plating can be used well.

[0023]

EXAMPLE An example of the magnetic recording head according to the present invention will be described below. In the above composition region, in order to improve the corrosion resistance at the time of production without impairing the magnetic properties, Cu was selected as an additional element and its composition range was examined. For comparison with this, a Cr-added film, which is generally considered to be effective for stainless steel or the like, was evaluated at the same time.

FIG. 2 is a diagram showing the relationship between the addition amount and the saturation magnetic flux density when Cu or Cr is added as the fourth element to the Co-Ni-Fe ternary alloy. Figure 3 shows Co
It is a figure which shows the relationship between the amount of addition and the hard axis coercive force at the time of adding Cu or Cr as a 4th element to a -Ni-Fe ternary alloy.

Even with the same amount of addition, the Cr-added film has a large decrease in the saturation magnetic flux density and a large increase in the coercive force as compared with the Cu-added film, so that the characteristics as a magnetic recording head are not preferable. .. On the other hand, the coercive force of the Cu-added film is almost equal to or less than that of the film not added. Thus, it was found that the addition of Cu does not hinder the magnetic properties.

FIG. 4 shows a graph of 1 in pure water at 80.degree.
It is a figure which shows the measurement result which immersed for time, measured the saturation magnetic flux density before and behind immersion, and determined the corrosion resistance of the material from the magnitude of the change amount. From the measurement results of FIG. 4, it was found that the Cu-added film had a normalized magnetization amount close to that before and after immersion even when added in a small amount as compared with the Cr-added film, and the corrosion resistance was improved.

FIG. 5 is a diagram showing the measurement results of determining the corrosion resistance of the material by measuring the polarization characteristics in a 80 ° C. hydrochloric acid aqueous solution maintained at pH = 4. Looking at the polarization characteristics of FIG. 5, the Cu-added film is
It can be seen that the natural electrode potential is shifted to the noble side, the corrosion current density is also reduced, the anode current density is reduced, the corrosion rate is small, and the corrosion resistance is improved. In the Cr-added film for comparison, the natural electrode potential shifts to the noble side,
The pitting potential is extremely small, and it is shown that the corrosion rapidly progresses due to a slight state change, such as contact between different metals during the process or local pH change. It is understood that Cr, which is generally known as an element forming a passivation region, has no effect on corrosion resistance when added at 10 at% or less. However, when it is added in an amount of 10 at% or more, the saturation magnetic flux density is remarkably reduced, and it cannot be realized as a high saturation magnetic flux density magnetic film.

The present invention comprehensively examines the above results,
Cu as an element that improves corrosion resistance without impairing magnetic properties
Was found and the composition range thereof was defined. That is, saturation magnetic flux density, coercive force, and corrosion resistance are basically
To a large extent. The Fe content is 15 at
% To 40 at% is desirable. Referring to FIGS. 9 and 10 described above, the Fe content is 15 at%.
If it is lower, the coercive force increases, which is not preferable. On the other hand, when it is more than 40 at%, the coercive force once lowered in the range of more than 15 at% increases again. Also, the corrosion resistance becomes poor. As a result, even if Cu is added,
The deterioration of the characteristics cannot be compensated.

The Co content is 40 at% to 70 at%.
Is desirable. When the Co content is 40 at% or less, the saturation magnetic flux density becomes low. On the other hand, if it exceeds 70%, the saturation magnetic flux density becomes high, but the coercive force becomes too large, hexagonal crystals (hcp) precipitate, the structure is unstable, and the coercive force increases, which is preferable. Absent.

The Cu content is preferably 1% to 10%. If the Cu content is 1% or less, the effect of improving the corrosion resistance is small. On the other hand, if it exceeds 10%, there is no problem with respect to corrosion resistance, but the saturation magnetic flux density decreases and the coercive force increases, which is not preferable. However, depending on the application, Cu may be 2
There is no problem in adding up to about 0 at%.

FIG. 6 shows a typical 3.5 of the films obtained by adding Cu as the fourth element to the Co-Ni-Fe ternary alloy.
The X-ray-diffraction pattern of an at% Cu addition film is shown. This thin film has a face-centered cubic structure, has a nearly perfect (111) plane orientation, and has the closest packed atomic plane on the film surface, and therefore has excellent corrosion resistance.

FIG. 7 is a partial sectional perspective view showing the entire structure of an embodiment of the magnetic disk device according to the present invention. The magnetic disk device includes a magnetic disk 1 for recording information, a motor 2 for rotating the magnetic disk 1, and a magnetic disk 1.
A magnetic head 3 for writing information to or reading information from the magnetic disk 1, an actuator 4 that supports the magnetic head 3 and determines a target position of the magnetic disk 1, and a voice coil motor 5.

FIG. 8 is a diagram conceptually showing the system configuration of the magnetic disk drive shown in FIG. The magnetic disk device has a magnetic disk 1 for recording information, a head slider 6 on which a magnetic head 3 for recording / reproducing information is mounted, and a head slider 6 is attached to stably maintain a submicron space with the magnetic disk 1. 7 for fixing, a guide arm 8 fixed with the spring 7 and driven by the actuator 4 and the voice coil motor 5, a disk rotation control system 9, a head positioning control system 10, and a recording / reproducing signal processing system 11. Consists of.

FIG. 1 is a partial sectional perspective view of an embodiment of a recording / reproducing separated type magnetic head including a magnetic recording head according to the present invention. The recording / reproducing separated type magnetic head of this embodiment, that is, the dual head 3, has an upper magnetic core 12, a lower magnetic core 13, a coil 14 for applying a recording current, and a reproducing head 15 mounted on a substrate 16. .. As a result of evaluating the performance of the dual head 3, it was confirmed that the dual head 3 showed excellent recording performance and was sufficiently recordable on a high coercive force recording medium.

Here, the effect of adding Cu to a typical Co-Ni-Fe ternary composition has been described.
By shifting the composition of the three-element system of o-Ni-Fe, the value of the saturation magnetic flux density can be changed as necessary. The crystal structure at that time is almost a face-centered cubic crystal. Co, N
Depending on the composition range, the i, Fe ternary alloys have α layers.
(Body centered cubic), γ phase (face centered cubic), and ε phase (hexagonal). In terms of magnetic properties, a γ-phase (face-centered cubic crystal) single phase is desirable, and it is unavoidable that a slight α-layer (body-centered cubic crystal) is mixed due to some difference in composition or manufacturing method. However, the α layer (body-centered cubic) is (Co-Fe)
Since it is a rich phase, it is not desirable to mix it in a large amount. F
When e is increased, a slight body-centered cubic crystal appears, but the volume is about 10% or less, and no problem in characteristics occurs.

Therefore, the additive element is preferably a γ-phase (face-centered cubic) stabilizing element such as Cu, and the platinum group element such as Pd can be expected to have the same effect as Cu. Thus, Co-Ni-F excellent in magnetic properties and corrosion resistance
When the e-Cu quaternary alloy thin film is used for the magnetic core of the magnetic recording head, the magnetic recording head having excellent recording characteristics can be obtained, which is sufficiently resistant to acid in the head manufacturing process.

[0037]

In the magnetic thin film of the present invention, Co, N
Since the composition of i, Fe, and Cu is limited to a predetermined range, the saturation magnetic flux density is sufficiently high, the coercive force is sufficiently low, and the corrosion resistance in the manufacturing process is particularly excellent in the magnetic characteristics after sputtering. In addition, since the anisotropic magnetic field is large even though the magnetostriction constant is a large positive value, the direction of magnetization in the magnetic domain structure in the magnetic core of the magnetic head is perpendicular to the magnetic path direction. It also exhibits excellent magnetic properties in the high frequency range.

By using the magnetic thin film having such magnetic characteristics in the magnetic core of the magnetic recording head, excellent recording performance can be obtained in a high recording density magnetic disk device corresponding to a high coercive force recording medium.

Furthermore, since the saturation magnetic flux density is high, the steepness of the magnetic field gradient of the head magnetic field distribution is large, and the recording wavelength can be subdivided by that amount, which is also effective for improving the recording density.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view of an embodiment of a recording / reproducing separated type magnetic head including a magnetic recording head according to the present invention.

FIG. 2 is a diagram showing the relationship between the amount of a fourth element added to a Co—Ni—Fe ternary alloy and the saturation magnetic flux density.

FIG. 3 is a diagram showing the relationship between the amount of a fourth element added to a Co—Ni—Fe ternary alloy and the hard axis coercive force.

FIG. 4 is a diagram showing the relationship between the amount of a fourth element added to a Co—Ni—Fe ternary alloy and the corrosion resistance from the viewpoint of saturation magnetic flux density.

FIG. 5 is a diagram showing the relationship between the addition of a fourth element and the corrosion resistance of a Co—Ni—Fe ternary alloy from the viewpoint of polarization characteristics.

FIG. 6 3.5 at to Co-Ni-Fe ternary alloy
It is a figure which shows the X-ray-diffraction pattern of the% Cu addition film.

FIG. 7 is a perspective view showing the overall structure of an embodiment of a magnetic disk device according to the present invention.

FIG. 8 is a diagram conceptually showing the system configuration of the magnetic disk device according to the present invention in FIG.

FIG. 9 is a diagram illustrating the relationship between the composition of a Co—Ni—Fe ternary system and magnetic characteristics.

FIG. 10 is a diagram showing a proper composition range of a Co—Ni—Fe ternary thin film for reaching the present invention.

[Explanation of symbols]

 1 magnetic disk 2 motor 3 magnetic head 4 actuator 5 voice coil motor 6 head slider 7 spring 8 guide arm 9 disk rotation control system 10 head positioning control system 11 recording / reproducing signal processing system 12 upper magnetic core of magnetic recording head 13 magnetic recording Lower magnetic core of head 14 Recording current applying coil 15 Playback head 16 Substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuya Mitsuoka 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitate Works Ltd., Hitachi Research Institute (72) Inventor Kenya Ohashi 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitsuru Corporation Hitachi, Ltd. (72) Inventor Shinji Shigeshi, 2880, Koufu, Odawara, Kanagawa Stock company, Hitachi Ltd., Odawara factory, Hitachi, Ltd. (72) Masakei Kagawa, 2880, Kozu, Odawara, Kanagawa, Ltd., Hitachi, Ltd., Odawara factory ( 72) Inventor Tetsuo Kobayashi 2880, Kozu, Odawara-shi, Kanagawa Stock company Hitachi, Ltd. Odawara factory (72) Inventor Shiro Kobayashi 4026, Kuji-machi, Hitachi City, Ibaraki Hitachi, Ltd. Hitachi Research Laboratory

Claims (5)

[Claims] 1. A magnetic recording head for a recording / reproducing separated type magnetic head, comprising a four-element alloy of Co, Ni, Fe and Cu, wherein the composition range of each element is Co: 40 to 70 at%, Ni. :
10-30at%, Fe: 15-40at%, Cu: 1
A magnetic recording head characterized in that a magnetic thin film having a content of 10 at% is used as a magnetic core. 2. The magnetic recording head for a recording / reproducing separated type magnetic head according to claim 1, wherein the crystal structure of the magnetic thin film is a face-centered cubic crystal.
1) A magnetic recording head characterized in that the planes are preferentially oriented. 3. At least one magnetic disk for recording information, means for rotating the magnetic disk, a magnetic recording head for writing information on the magnetic disk, and a magnetic reproducing head for reading information from the magnetic disk. In a magnetic disk device comprising a recording / reproducing separated type magnetic head and a support driving means for supporting the recording / reproducing separated type magnetic head and driving it to a target position, the magnetic recording head comprises Co, Ni, Fe and Cu. And a composition range of each of the above elements is Co: 4.
0 to 70 at%, Ni: 10 to 30 at%, Fe: 15
A magnetic disk device comprising a magnetic recording head having a magnetic core of a magnetic thin film of -40 at% and Cu: 1-10 at%. 4. The magnetic disk device according to claim 3, wherein the crystal structure of the magnetic thin film is face-centered cubic.
1) A magnetic disk drive characterized in that the planes are preferentially oriented. 5. A four-element alloy of Co, Ni, Fe, and Cu, wherein the composition range of each element is Co: 40-70.
at%, Ni: 10 to 30 at%, Fe: 15 to 40a
t%, Cu: 1 to 10 at% Magnetic thin film for magnetic recording head.