JPH0785451B2 - High permeability multilayer magnetic film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic film having a high magnetic permeability even in a high frequency region and a low coercive force, and in particular, a high magnetic permeability even when processed into a magnetic pole shape. The present invention relates to a high-permeability multilayer magnetic film that maintains magnetic susceptibility and obtains excellent magnetic characteristics.

[Background of the Invention]

Conventionally, in order to improve the high frequency characteristics of magnetic films,
A method of laminating via a non-magnetic intermediate layer such as SiO ₂ is known. In fact, as shown in Japanese Patent Laid-Open No. 58-192311, a conventional multilayer magnetic film, for example, Fe--Si and a non-magnetic Si film is used.
It is known that in a multilayer magnetic film in which O ₂ is laminated as an intermediate layer, the grain size of Fe-Si itself becomes small due to lamination, so that anisotropy dispersion is suppressed and the magnetic characteristics of the film are improved. ing. Here, the thickness of the magnetic film is 0.01-0.2μ
m, the film thickness of the intermediate layer is appropriately 1 nm to 10 nm. This is because there is a pinhole in the film pressure of about several nm, and exchange interaction works between the Fe-Si layers through this pinhole, and each layer becomes ferromagnetic while the anisotropy dispersion is suppressed. This is because the magnetic properties of the entire film are improved due to the coupling. On the other hand, in order to further improve the high frequency characteristics of these multilayer magnetic films, it is necessary to reduce the eddy current loss at high frequencies, and as described in JP-A-59-9905, the above-mentioned multilayer films are disclosed. There is also an attempt to stack the layer with a thicker non-magnetic insulating layer. In this case, in order to improve the high frequency characteristics, it is desirable that the thickness of the nonmagnetic intermediate layer be 0.05 to 1 μm. However, when such a multilayer film is patterned into a magnetic pole shape so as to be applied to a thin film magnetic head as shown in FIGS.
As shown in FIG. 11, the magnetic permeability in (1) is reduced to about 1/10 of that of the initial film before patterning, and good head characteristics cannot be obtained.

[Object of the Invention]

An object of the present invention is to provide a high-performance, high-permeability multi-layered magnetic film that eliminates such drawbacks.

[Outline of Invention]

In the conventional multilayer magnetic film, since the layers are ferromagnetically coupled, the direction of magnetization cannot be changed in the film thickness direction. Therefore, if such a multilayer magnetic film is applied to a thin film magnetic head, the direction of magnetization in the plane is reduced in order to reduce the influence of the demagnetizing field at the magnetic core end when patterned into a magnetic core shape. Was adjusted and the bitter pattern of the magnetic pole was observed, the triangular magnetic domain as shown in Fig. 10 was observed.
By forming 131 and 132, the free magnetic pole does not occur at the end of the magnetic core. Inside the triangular domain, the easy axis of magnetization is oriented in the direction of the magnetic path of the magnetic core. Therefore, especially when trying to excite or reproduce a recording signal at a high frequency, the response of this part is slow, and as a result the entire magnetic pole is It was clarified that the effective permeability decreased and the recording / reproducing characteristics of the head deteriorated.

This phenomenon is more remarkable as the saturation magnetic flux density Bs of the magnetic material is larger, which is a particular problem.

The inventors of the present invention have conducted various experiments and logical studies on the above problems with various film structures, and show that a multilayer film made of a magnetic material having a large Bs has good magnetic permeability even after patterning as described below. Invented the magnetic film of That is, in order to improve the magnetic characteristics of the patterned ferromagnetic thin film, a unit magnetic film in which ferromagnetic materials are stacked via an intermediate layer is further stacked via another intermediate layer of 10 to 40 nm in thickness. To do. The material for the two or more intermediate layers is preferably a combination of two or more of ferromagnetic, non-magnetic, and antiferromagnetic materials. This is because the unit magnetic film is further laminated via the second intermediate layer so that the magnetic permeability is not deteriorated even after the fine pattern is processed as shown in FIG. Conventionally, IEEE Trans, Mag
n., Vol1.Mag-13, pp.1521-1523, there was an example in which a magnetic film Ni-Fe was laminated with an intermediate layer Cu having a thickness of 10 nm to obtain the same effect. The feature of the present invention is that two kinds of materials are used for the intermediate layer, and it has been confirmed that there is a remarkable effect as compared with the conventional example.

FIG. 11 shows the result of unit magnetic film in which the magnetic material was 0.1 μm, 7 wt% Si-Fe, and 5 layers were laminated with 20 wt% Fe-Ni as the first intermediate layer of 3 nm thickness. However, the magnetic material may be Co-Fe, Fe-Ti or Co-Zr, Co-ZrMo, and the first intermediate layer is made of ferromagnetic Ni, Fe, Co, F.
The same effect was obtained with e ₂ O ₃ , antiferromagnetic NiO, and Mn-Fe. Here, as shown in FIG. 12, the thickness of one layer of the Fe—Si magnetic material is preferably 0.01 to 0.2 μm, more preferably 0.04 μm.
˜0.12 μm is preferred. This is because the magnetic film thickness is 0.01 μm
This is because if the thickness is thinner, the magnetic properties are likely to deteriorate due to thermal stress and the like, and conversely, if it is thicker than 0.2 μm, the crystal grains become large, which deteriorates the magnetic properties. Further, the second intermediate layer was made of SiO ₂ having a film thickness of 20 nm, but similar results were obtained when Al ₂ O ₃ , Ti, Mo, W, or the like was used. Here, the thickness of the first intermediate layer is preferably 1 to 10 nm, more preferably 2 to 8 nm as shown in FIG. This is because if the thickness is less than 1 nm, the quality of the intermediate layer is poor, and crystal grains grow through the pinholes, deteriorating the magnetic characteristics. This is because the characteristics deteriorate. Further, as the film thickness of the second intermediate layer,
As shown in FIG. 14, the thickness is preferably 10 to 40 nm, more preferably 15 to 30 nm. This is because when the film thickness is thinner than 10 nm, the interaction between the unit magnetic layers is strong and the magnetization directions of the respective layered layers are the same, which deteriorates the magnetic characteristics after patterning. This is because when the thickness is more than 40 nm, the magnetic characteristics of each unit magnetic film itself are deteriorated due to the existence of the thick intermediate layer.

As described above, in the present multilayer magnetic film, the magnetization directions are opposite to each other in each unit ferromagnetic layer, so that even if a free magnetic pole occurs at the end of the magnetic core, the free magnetic pole of the reverse magnetic field is formed in the vicinity thereof. Therefore, the increase in magnetostatic energy is extremely small, and it is not necessary to form the triangular magnetic domains 131 and 132 shown in FIG. Considering the compensation effect of the free magnetic pole, this effect is
If the film thickness is the same, it is more remarkable that the total number of unit magnetic films is even. In any case, as a result, even if the magnetic film is processed into a magnetic core shape, it is possible to prevent the deterioration of the magnetic properties as shown in FIG. It is particularly effective for a magnetic film having a large saturation magnetic flux density of 1.2 T or more, more preferably 1.5 T or more, which is easily formed, and the unit magnetic film has a thickness of 0.05 to 0.9 μm, further 0.09 to 0.2. It is remarkable in the case of μm. In terms of reproducibility and reliability, Fe-
Si or Fe-Si-Ru, a Ni-Fe alloy of the first intermediate layer, it is more preferable to use SiO ₂ or Al ₂ O ₃ in the second intermediate layer.

As described above, the multilayer film of this structure is excellent in magnetic characteristics particularly when the thin film is patterned into a magnetic pole shape, and the characteristics of the thin film magnetic head using the multilayer film of this structure are different from those of other structures. 2 times more excellent than In particular, a thin film head using the present multilayer film for the main pole is excellent as a head for perpendicular magnetic recording because the magnetic characteristics do not deteriorate even if it is a thin film.

Example of Invention

 An embodiment of the present invention will be described below in detail.

FIG. 1 shows an example of the multilayer structure of the multilayer magnetic film of this embodiment. The multilayer magnetic film of the present invention comprises a main magnetic material layer 11, 12, 13, 14 made of a high saturation magnetic flux density material and a main magnetic material layer 11, 1.
The first intermediate layers 15 and 16 which maintain the ferromagnetic coupling between 2, 13 and 14,
The main magnetic material layers 11, 12, 13 and 14 are separated from each other by a second intermediate layer 17 for separating the ferromagnetic coupling. The main magnetic materials of high saturation magnetic flux density materials are Fe-Si system, Fe-Ge system, Fe-Ti system.
A material containing Fe as a main component is more preferable from the viewpoint of the saturation magnetic flux density, which can use an Al-based, Fe-N-based, Co-Fe-based, Co-Zr-based, Co-Ti-based, Co-Ta-based alloy. First middle layer 15,1
As for 6, in addition to Ni-Fe alloys, ferromagnetic materials such as Co, Si
A non-magnetic material such as O ₂ , Al ₂ O ₃ , Al, Ti and Mo, or an antiferromagnetic material such as Fe-Mn can be used. As the second intermediate layer 17,
A non-magnetic material such as SiO ₂ , Al ₂ O ₃ , Al, Ti, Mo or an antiferromagnetic material such as Fe-Mn can be used. Table 1 summarizes examples of this structure. These can be formed by a sputtering method, a vapor deposition method, or the like. The non-magnetic intermediate layer can also be obtained by introducing oxygen into a sputtering device to oxidize the surface of the magnetic layer.

The thickness of the main magnetic material layers 11, 12, 13, and 14 is not limited to this, and is 0.01 μm to 0.2 μm, and more preferably 0.04 μm to 0.12 μm, which gives a small crystal grain size. First middle layer
As described above, it is desirable that the film thicknesses of 15 and 16 be as thin as 1 to 10 nm, preferably 2 to 8 nm so as to maintain the ferromagnetic coupling of the magnetic film formed therethrough. Further, when a non-magnetic film is used as the first intermediate layers 15 and 16, it is desirable to make the film thickness thinner than when a magnetic film is used. The thickness of the second intermediate layer 17 is 10 nm to 40 n so that the ferromagnetic coupling of the magnetic film formed therethrough is cut off.
m, more preferably 15 nm to 30 nm and the first intermediate layer 15, 16
It is more desirable to be thicker than this. Magnetic film The thickness of the unit magnetic film formed by laminating the first intermediate layer 15 and the first intermediate layer 15 and 16 is more than 0.05 to 0.9 μm, more preferably 0.09 to 0.2 μm because the effect of a demagnetizing field appears when the thickness is made too thick. It is desirable to do.

Examples of the thin film head manufactured by using the multilayer film of this structure will be described in detail below.

Fe-6.5wt% Si-1wt% Ru alloy with saturation flux density of 1.7T, Fe-6.5wt% -1
Ni-20 wt% Fe was used as the intermediate layer for ferromagnetically coupling the wt% Ru alloy layers, and SiO ₂ was used as the nonmagnetic layer for separating the ferromagnetic coupling between the ferromagnetic layers. Fe-6.5wt% Si-1
The thickness of one layer of the wt% Ru alloy is kept constant at 0.05 μm, and Ni-20
The thickness of the wt% Fe alloy is 5 nm, and the thickness of one layer of SiO ₂ is 0, 5, 1
A multilayer magnetic film having a multilayer structure shown in FIG. 1 was formed with a thickness of 0, 20, 50, 90, 100, and 150 nm, and a thin film head shown in FIG. Here, 51 is a non-magnetic substrate such as Al ₂ O ₅ , TiC, Al ₂ O ₃ and ZrO ₃ , 52 is the multilayer film, 53 is a gap layer composed of Al ₂ O ₃ and SiO ₂ , and 54 is Cu and Al. Coil made of etc., 55 is an insulating layer made of polyimide resin, SiO ₂ etc., 56 is CoZrW, CoZ
It is a magnetic layer made of r, Ni-Fe, or the like. Note that Fe-Si-Ru
Alloy, Ni-Fe alloy, such as SiO ₂ was formed by RF sputtering. If the thickness of the intermediate layer SiO ₂ is 0.5 nm, the SiO ₂
There is almost no effect of the intermediate layer, and the magnetic permeability of the patterned magnetic film at 10 MHz is as low as about 200. Observation of the magnetic domain structure at this time revealed that extremely large triangular magnetic domains 31 were formed as shown in FIG. When the thickness of the SiO ₂ intermediate layer was 10 nm or more, the effect of SiO ₂ was exerted, and the magnetic permeability was about 1000 to 1500. Observation of the magnetic domain structure at this time revealed that almost no triangular magnetic domains were formed as shown in FIG.

If the film thickness of the SiO ₂ intermediate layer is too large, the magnetic properties of the initial film deteriorate and the magnetic permeability after patterning also decreases. Fig. 5 shows saturation magnetization Ms300emu / cc, coercive force H
_{c ⊥} 500 Oe, film thickness t _m 0.2 μm Co-Cr perpendicular magnetic layer 0.7
The reproducing output of this head evaluated by using a two-layer film medium formed on a Co-Zr-Mo soft magnetic layer of μm is shown. It was found that good characteristics were obtained when the thickness of the SiO ₂ intermediate layer was 10 nm to 40 nm.

FIG. 6 shows an embodiment of another thin film magnetic head using the above-mentioned multilayer magnetic film of the present invention. 71 is a ferromagnetic substrate, 75
Is a main pole using the multilayer magnetic film shown in FIG. 1, 72,74
Is an insulating layer made of SiO ₂ , Al ₂ O ₃ or the like, and 73 is a conductor coil made of Al, Cu or the like. In FIG. 8, the tip thickness of the multilayer magnetic film 75 is 0.02,0.035,0.05,0.1,0.3,0.6,1,2,5,
Recording density characteristics when changing to 10 μm, Ms is 800 emu / cc,
Co-Cr medium with H _{c ⊥} of 700 Oe and t _m of 0.3 μm and film thickness of 0.9
The results of evaluation using a two-layer film medium composed of a CoZrMo high-permeability underlayer of μm are shown. From this, in order to extend the recording density characteristics, the previous film thickness is 0.035 to 1 μm, preferably 0.05.
It can be seen that the thickness is ˜0.5 μm, and more preferably 0.1 to 0.4 μm. In this case, in order to prevent magnetic saturation of the main pole, the saturation magnetic flux density is 1.2T or more, more preferably 1.5T.
It is desirable to have more than one. The multilayer film of the present invention has a magnetic permeability (10 MHz) of about 1500 even after being processed into a main magnetic pole shape, and by using this, a thin film magnetic head with extremely excellent reproducibility can be obtained.

〔The invention's effect〕

In the present invention, even if the magnetic pole shape of the magnetic head is processed,
A magnetic film having a high magnetic permeability of about 1500 in the high frequency range of z and a high saturation magnetic flux density can be obtained. When this is used as a core material for a thin film magnetic head, the head performance can be remarkably enhanced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a multilayer structure of the multilayer film of the present invention, FIGS. 2 and 3 are magnetic domain pattern diagrams generated in a magnetic core,
FIG. 4 is a cross-sectional view for explaining a thin film magnetic head manufactured using the multilayer magnetic film of the present invention, and FIG. 5 is a cross-sectional view when the multilayer magnetic film of the present invention is applied to the thin film magnetic head. FIG. 6 is a diagram showing the dependency of the head reproduction output on the thickness of the intermediate layer SiO ₂ , and FIG. 6 is a cross-sectional view for explaining another thin film magnetic head manufactured by using the multilayer magnetic film of the present invention. FIG. 8 is a diagram showing the dependence of the recording density of the magnetic head shown in FIG. 6 on the film thickness of the magnetic pole tip, and FIG. 8 is a diagram for explaining a thin film magnetic head as an application example of the present invention. 8A is a cross-sectional view, FIG. 8B is a top view, and FIG. 9 is a diagram showing a magnetic permeability after patterning a conventional multilayer magnetic film into a magnetic pole core shape and a track width of the magnetic pole core. Fig. 10 shows the relationship, Fig. 10 is a magnetic domain pattern diagram that appears when a conventional multilayer magnetic film is patterned into a magnetic pole shape, FIG. 11 is a diagram comparing magnetic permeability after patterning the multilayer magnetic film of the present invention into a magnetic pole shape, and FIG. 12 is a main magnetic field of the magnetic permeability of the multilayer magnetic film of the present invention. FIG. 13 is a diagram showing the layer thickness dependency, FIG. 13 is a diagram showing the first intermediate layer thickness dependency of the magnetic permeability of the multilayer magnetic film of the present invention, and FIG. 14 is the magnetic permeability of the present invention. FIG. 5 is a diagram showing a relationship with the second intermediate layer film thickness. 51 …… Non-magnetic substrate, 52 …… Main pole, 53 …… Gap layer, 54
...... Conductor coil, 55 …… Insulation layer, 56 …… Auxiliary pole, 71 ……
Ferromagnetic substrate, 72 ... Gap layer, 73 ... Conductor coil, 74 ...
… Insulating layer, 75… Main pole, 111… Non-magnetic substrate, 112… Lower magnetic layer, 113… Upper magnetic layer, 114… Conductor coil, 115…
… Gap layer.

Front page continuation (72) Inventor Isamu Yubito 1-280, Higashi Koigakubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory (72) Inventor Hitoshi Nakamura 1-280, Higashi Koigakubo, Kokubunji, Tokyo Hitachi Central Research Co., Ltd. In-house (72) Climbing Kumasaka, Inventor 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Shigeichi Otomo 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56 ) Reference JP 59-157826 (JP, A) JP 53-33398 (JP, A) JP 59-61104 (JP, A) JP 58-192311 (JP, A) JP 60-189906 (JP, A) JP-A-60-117606 (JP, A)

Claims (4)

[Claims] 1. A thickness made of a material having a saturation magnetic flux density of 1.2 T or more.
The ferromagnetic layer having a thickness of 0.01 to 0.2 μm is provided through a first intermediate layer having a thickness of 1 to 10 nm, which is made of a ferromagnetic layer, a nonmagnetic layer or an antiferromagnetic layer different from the ferromagnetic layer. To form a unit magnetic film having a thickness of 0.05 to 0.9 μm, the unit magnetic film having a thickness of 10 to 40 nm as a first intermediate layer composed of a nonmagnetic layer or an antiferromagnetic layer. Is a high-permeability multilayer magnetic film formed by vertically stacking another kind of second intermediate layer. 2. The thickness of the ferromagnetic layer is 0.04 to 0.12 μm,
The high-permeability multilayer according to claim 1, wherein the thickness of the intermediate thin layer is 2 to 8 nm, the thickness of the unit magnetic film is 0.09 to 0.2 μm, and the thickness of the intermediate layer is 15 to 30 nm. Magnetic film. 3. The high magnetic permeability multilayer magnetic film according to claim 1 or 2, wherein the intermediate thin layer is made of a ferromagnetic material and the intermediate layer is made of a non-magnetic material. 4. The high-permeability multilayer magnetic film according to claim 1, further comprising an even number of the unit magnetic films.