JP3233538B2 - Soft magnetic alloys, soft magnetic thin films and multilayer films - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a soft magnetic alloy, a soft magnetic thin film, and a multilayer film.

[0002]

2. Description of the Related Art In the field of magnetic recording, a magnetic recording medium having a high coercive force has been used along with an increase in recording density. In this case, in order to perform good magnetic recording, it is necessary to generate a high-density magnetic flux from the magnetic head. Therefore, metal-in using a soft magnetic thin film or a soft magnetic multilayer film having a high saturation magnetic flux density (Bs) is required.・ Gap (MI
G) type magnetic heads, laminated magnetic heads, thin film magnetic heads, and the like have been used. The soft magnetic thin film and the soft magnetic multilayer film used in these magnetic heads are required to have high Bs, low coercive force (Hc) and high magnetic permeability (μ). In particular, in a magnetic head for a high-density recording medium, it is important that the magnetic permeability at a high frequency (for example, about 10 MHz) is large.

Some soft magnetic materials having a high Bs of 15 kG or more have been proposed, but other characteristics are not sufficient.

[0004] For example, as a system showing high Bs, a system containing Fe or an Fe-Co alloy as a basic component is known. However, Fe-Co alloy materials have large magnetostriction.
For this reason, even if the substrate temperature and the heat treatment temperature are optimized when forming by the sputtering method, Hc becomes high and sufficient soft magnetic characteristics cannot be obtained.

As a technique for improving the soft magnetic characteristics of Fe-based materials, it has been proposed to add N and O to Fe by several percent or less (Japanese Patent Application Laid-Open No. 2-57665). It has Bs of 15 kG or more and Hc of 1.5 O
e, which shows good soft magnetic properties, but has poor corrosion resistance, and easily oxidizes in an environment of normal temperature and normal humidity, causing a problem that the magnetic properties are significantly deteriorated. In addition, there is a problem in heat resistance, and characteristics are deteriorated due to heat inevitably applied during element fabrication.

[0006] In the summary of the 16th Annual Meeting of the Japan Society of Applied Magnetics, 7pF-15, Co = 50-60 wt%, Fe = 2
It is reported that a plating film containing 0 to 30 wt% and Ni = 20 to 30 wt% can provide high Bs of 19 kG or more and good corrosion resistance. However, this plating film has a magnetic permeability (μ) of about 600 to 700, which is lower than that of Permalloy. In addition, the reference does not describe the measurement frequency of the magnetic permeability.

The ternary composition diagram of FIG. 1 of JP-B-63-53277 shows that the λ in the Fe—Co—Ni plating film is
Although the s = 0 line is shown, this publication does not measure magnetic permeability at high frequencies. The high-Bs Fe described in the 16th Annual Meeting of the Japan Society of Applied Magnetics,
It is considered that the magnetic permeability of the -Co-Ni plated film is low because the absolute value of λs is large.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing Fe
-High Bs for Co-Ni soft magnetic alloys, especially for thin films
And realizing high magnetic permeability at high frequencies.

[0009]

This and other objects are achieved by any one of the following constitutions (1) to (3). (1) Fe, the Co and Ni, Ti is added and / or Hf, the atomic ratio of each element is represented by the formula _{(Fe x Co y Ni z)} 100-ab Ti a Hf b 0.10 ≦ x ≦ 0 in .55, 0.20≤y≤0.85, 0.05≤z≤0.28, 3x-5z≤0.60, x + y + z = 1, 0≤a≤5, 0≤b≤3, 0.1 ≤a + b≤5, consisting essentially of a face-centered cubic single phase, with a saturation magnetostriction value of λs, a face-centered cubic (111) face spacing of d (111), and Ti and Hf When neither is included, the (111) plane interval of the face-centered cubic is d ₀ (111)
When Δd (111) = d (111) −d ₀ (111), 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (111) ≦ 3.0 × 10 ⁻⁸ Some soft magnetic alloys. (2) A soft magnetic thin film composed of the soft magnetic alloy of (1). (3) A multilayer film in which at least one layer is the soft magnetic thin film of (2).

[0010]

According to the present invention, the main composition of Fe-Co-Ni soft magnetic alloy, especially thin film, is Fe, Co
And Ni and the composition range of Ni and Ti and / or Hf are added, and λs · Δd (111) / d ₀ (11
1) is set in a predetermined range. By adding Ti or Hf, crystal grains become finer, and magnetostriction and lattice spacing change. In the present invention, by adding a predetermined amount of Ti or Hf and setting the composition ratio of Fe, Co and Ni within a predetermined range, the refinement of crystal grains and the magnetoelastic effect act synergistically to provide excellent softness. High magnetic permeability is obtained at magnetic properties, particularly at high frequencies of about 10 MHz. Note that the magnetoelastic effect is caused by magnetostriction and internal stress caused by distortion of the lattice. Further, in addition to excellent soft magnetic properties, heat resistance to withstand heat treatment at 500 ° C. is obtained, and a high saturation magnetization of 15 kG or more can be obtained.

Conventionally, in a Fe—Co—Ni alloy,
It is difficult to achieve both high Bs and high magnetic permeability, and no proposal has been made to achieve high magnetic permeability particularly at high frequencies. However, according to the present invention, high magnetic permeability at high frequencies can be obtained even in a composition range in which high Bs can be obtained. Can be obtained.

Table 1 of JP-A-2-68906 discloses that
Fe ₄₂ Co ₁₈ Ni ₃₅ T formed by sputter deposition
i ₄ and Fe ₄₃ Co ₁₉ Ni ₃₅ Hf ₃ is described. These compositions are similar to the present invention in that Ti or Hf is added to the Fe—Co—Ni alloy, but Fe, C
Since the ratio of o and Ni is largely out of the range limited by the present invention, λs · Δd (111) / d ₀ (111) does not fall within the range limited by the present invention, and is naturally equivalent to the present invention. The effect of is not realized. The publication only describes the initial permeability, but does not pay any attention to the permeability at a high frequency of about 10 MHz.

Japanese Patent Application Laid-Open No. 64-8605 discloses that
A soft magnetic thin film in which Fe ₂₉ Co ₄₀ Ni ₂₉ Ti ₂ thin films and Fe ₈₆ Si ₁₄ thin films are alternately laminated is described. Fe ₂₉ C
o ₄₀ Ni ₂₉ Ti ₂ thin film, Fe-Co-Ni alloy Ti
Is similar to the present invention in that Fe, Co, N
Since the ratio of i is out of the range limited by the present invention,
An effect equivalent to that of the present invention is not realized. In this publication, 10MH
No attention is paid to magnetic permeability at high frequencies of the order of z.

[0014]

[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail.

The soft magnetic alloy of the present invention contains Fe, Co and Ni as main components, and Ti and / or H as an additive.
f. Atomic ratio of each of these elements has the formula _{(Fe x Co y Ni z)} 100-ab Ti a Hf b 0.10 ≦ x ≦ 0.55 in, 0.20 ≦ y ≦ 0.85, 0.05 ≦ z ≦ 0.28, 3x−5z ≦ 0.60, x + y + z = 1, 0 ≦ a ≦ 5, 0 ≦ b ≦ 3, 0.1 ≦ a + b ≦ 5, preferably 0.10 ≦ x ≦ 0.45, 0.40≤y≤0.85, 0.05≤z≤0.15, 3x-5z≤0.60, x + y + z = 1, 0.5≤a≤2, 0.5≤b≤ 1, 0.5 ≦ a + b ≦ 3. FIG. 1 shows the limited ranges of x, y and z representing the atomic ratios of Fe, Co and Ni. Specifically, when 3x-5z> 0.60, body-centered cubic crystals are likely to precipitate. If z is too small, a body-centered cubic crystal is likely to precipitate. If z is too large, high Bs
Can not be obtained. If x is too small, hexagonal close-packed crystals will precipitate and a face-centered cubic structure cannot be obtained. On the other hand, if a + b is too small, the effect of the addition of Ti or Hf becomes insufficient, and high magnetic permeability cannot be obtained at high frequencies. If at least one of a, b, and a + b is too large, precipitation of a body-centered cubic crystal or precipitation of a compound phase such as Hf-Co may occur.
High permeability cannot be obtained at high frequencies.

In order to improve corrosion resistance and wear resistance, part of Fe is replaced with Cr, Cu, Sn, Rh, Pd, M
It may be replaced with at least one element selected from n, P, B, Zn, Sn, Pt and the like. In order to suppress a decrease in Bs, the content of these elements is preferably set to 3% by weight or less.

The soft magnetic alloy of the present invention is substantially composed of a face-centered cubic single phase. When the body-centered cubic single phase or the mixed crystal of the face-centered cubic phase and the body-centered cubic phase is used, the effect of the present invention cannot be obtained. However, since the composition range of the main component in the present invention is adjacent to the composition range in which the body-centered cubic phase is eutectoid, a very small amount of body-centered cubic crystal is locally segregated to form a special structure, It is conceivable that high characteristics are obtained by this. Therefore, “substantially face-centered cubic single phase” in the present invention is an evaluation result when a general-purpose X-ray diffractometer is used, and is a concept including the special structure as described above. Note that the crystal structure can be confirmed by X-ray diffraction.

The average crystal grain size of the soft magnetic alloy of the present invention is 2
It is preferably from 0 to 350A. Since the crystal grains are refined in this way by the addition of Ti or Hf, good soft magnetic characteristics can be obtained.

In the soft magnetic alloy of the present invention, the saturation magnetostriction value is λ
s and the distance between the (111) planes of the face-centered cubic crystal is d (111)
When Δd (111) = d (111) −d ₀ (111), 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (11
1) ≦ 3.0 × 10 ⁻⁸ , preferably 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (11
1) ≦ 2.0 × 10 ⁻⁸ . However, d ₀ (111) is the (111) plane interval of the face-centered cubic crystal when the ratio of Fe, Co and Ni is the same and neither Ti nor Hf is included. The soft magnetic alloy of the present invention is substantially composed of face-centered cubic, and (11)
1) The plane is preferentially oriented. Since the magnetoelastic effect contributes to the soft magnetic characteristics, in the present invention, λs · Δd (111) / d _{0 is} used as an index for estimating the contribution by the magnetoelastic effect.
(111) was defined, and the correlation with soft magnetic properties, particularly magnetic permeability at high frequencies, was examined. It has been found that high magnetic permeability can be obtained at a high frequency in the above range, for example, 500 or more at 10 MHz. Note that d (111) is Cu
In X-ray diffraction using Kα ₁ ray, the face-centered cubic (1
11) It can be calculated from the diffraction angle 2θ of the plane.

In the soft magnetic alloy of the present invention, when the peak intensity on the (200) plane and the peak intensity on the (111) plane in X-ray diffraction are I (200) and I (111), respectively, I (200) ) / I (111) ≦ 0.4. In the case of face-centered cubic, the (111) plane is preferentially oriented. Magnetostriction depends on the crystal orientation.
In 166406, the composition and manufacturing conditions are optimized so that I (200) / I (111) falls within a predetermined range. On the other hand, in the present invention, λs · Δd (111) / d
_Since high magnetic permeability is obtained by controlling ₀ (111), it is not necessary to simply reduce only λs. Therefore,
There is no need to strictly control I (200) / I (111) for the purpose of reducing λs, and the productivity is improved.

Next, a method for producing the soft magnetic alloy of the present invention will be described.

The soft magnetic alloy of the present invention is formed into various shapes such as a thin film, a ribbon, and a plate depending on the application.

For the production of a soft magnetic alloy in the form of a thin film, a method of forming a thin film in a gas phase such as a sputtering method, a vapor deposition method, an ion plating method or a CVD method, or a liquid method such as an electroplating method. Although a method of forming a thin film in a phase can be used, it is generally preferable to use a method of forming a thin film in a gas phase.

When the sputtering method is used, a cast or sintered body of an alloy may be used as a target, and a composite target may be used. Further, a bias sputtering method may be used for controlling the crystal orientation. The bias voltage is -30 to-
Preferably, it is 200V.

When the evaporation method is used, the substrate temperature is set to 40
The temperature is preferably set to 0 ° C. or lower.

Since a thin film formed by a sputtering method or a vapor deposition method has an internal stress, which makes it difficult to obtain good soft magnetic characteristics, it is preferable to perform a heat treatment for relaxing the stress after forming the film. This heat treatment is preferably performed in a vacuum or an inert gas atmosphere, the holding temperature is preferably 300 to 700 ° C., and the processing time is 1 hour.
２2 hours are preferable.

When an electroplating method is used, a conductive film is formed as a base film by a sputtering method, a vapor deposition method, or the like.
A thin film of a soft magnetic alloy is formed thereon. It is preferable to use permalloy or Fe for the base film. This allows
The desired crystal orientation is easily obtained.

The soft magnetic alloy thin film is preferably provided with uniaxial anisotropy in a desired direction. As a method for imparting uniaxial anisotropy, film formation in a magnetic field or annealing in a magnetic field after the film formation can be used.

The film formation in a magnetic field and the annealing in a magnetic field can be applied to any of the above-described methods. When a sputtering method or a vapor deposition method is used, annealing in a magnetic field can be replaced with the above-described heat treatment for stress relaxation.

The thickness of the soft magnetic thin film formed by each of the above-mentioned methods may be appropriately determined according to the purpose, and is not particularly limited.
The thickness is preferably about 5 to 10 μm, more preferably about 0.5 to 4.5 μm when applied to a thin film magnetic head, and about 3 to 10 μm when applied to a thin film transformer.

The soft magnetic thin film of the present invention can be applied to a multilayer film. Other layers of the multilayer film include SiO ₂ , Si ₃
A non-magnetic insulating thin film such as N ₄ or another soft magnetic thin film may be used. By using a multilayer film, good soft magnetic characteristics can be obtained, and a magnetic head with low loss can be realized.

For the production of a ribbon-shaped soft magnetic alloy, it is preferable to use a liquid quenching method. In the liquid quenching method, a molten alloy is injected, brought into contact with a surface of a cooling base such as a cooling roll, and rapidly cooled to produce a ribbon-shaped soft magnetic alloy. The liquid quenching method includes a single roll method that cools the molten alloy from one direction,
There is a twin roll method to cool from two opposite directions,
In the present invention, it is preferable to use a single roll method. In order to produce a soft magnetic alloy having the above-described crystal orientation, various conditions such as the cooling rate of the molten alloy and the thickness of the ribbon may be appropriately selected. The preferred ranges of these conditions vary depending on the alloy composition. For example, the cooling rate is generally 1 × 10 ³ to
It is preferably 1 × 10 ⁶ K / s, particularly preferably 1 × 10 ⁴ to 1 × 10 ⁶ K / s, and the thickness of the ribbon is generally 3 to 100 μm.
It is particularly preferable that the thickness be 10 to 70 μm.

In addition to these methods, a soft magnetic alloy having a predetermined shape may be manufactured by a casting method or the like.

The soft magnetic alloy in the form of a thin film is, for example, MIG
Applied to magnetic shield films, magnetoresistive films, thin film transformers, etc., for inductive magnetic heads of type, stacked type, thin film type, and magnetoresistive effect type magnetic heads. The soft magnetic alloy formed into a plate shape or the like by a casting method is applied to, for example, a magnetic shield plate or the like, but the soft magnetic alloy of the present invention is also applicable to various magnetic devices other than these. It is possible.

[0035]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

A soft magnetic thin film was formed on a slide glass (manufactured by MATSUNAMI) substrate by RF magnetron sputtering to obtain a sample for measurement.

The target was Fe-Co with a diameter of 90 mm.
When using a composite target in which Ni chips are arranged in an annular shape on an alloy target and adding Ti or Hf,
Similarly, Ti chips and Hf chips were arranged in an annular shape. Sputtering was performed in Ar gas. Ultimate pressure is 5 × 10 ^-7
Torr or less, pressure during film formation is 10 × 10 ⁻³ Torr, RF power is 200 to 400 W, and film formation speed is 40 to 150 A / s.
And the film thickness was about 5000 A. The cooling of the substrate during sputtering was not particularly performed.

After the film is formed, in order to reduce the stress in the film,
It was kept at 500 ° C. for 1 hour under a pressure of 1 × 10 ⁻⁵ Torr or less.

The following measurements were performed for each sample. The results are shown in each table.

The film composition was measured by X-ray fluorescence analysis.

Saturation magnetic flux density (Bs), coercive force (Hc) Using a VSM (sample vibrating magnetometer), a maximum applied magnetic field of 10
It was measured in kOe.

A sample having a saturation magnetostriction value (λs) is placed in a magnetic field of 100 Oe rotating in the film plane, and the expansion and contraction due to the magnetostriction of the sample is detected by a synchronous rectification method using a laser beam to calculate λs. did. The sample for measuring the saturated magnetostriction value has a thickness of 0.1 mm.
A 15 mm glass plate was used as a substrate.

Δd (111) / d _{0 The} (111) face interval d (111) of the (111) face-centered cubic structure is Cu
By X-ray diffraction using Kα ₁ ray, (1
11) The diffraction angle 2θ of the plane was determined and calculated from this. Then, using the (111) plane spacing d ₀ (111) of the sample having the same composition ratio of the main component and containing neither Ti nor Hf, Δd (111) = d (111) −d ₀ (111) Δd (111) was obtained and calculated.

The average crystal grain size was determined from the half width of the peak of the (111) plane of the face-centered cubic structure by X-ray diffraction using CuKα ₁ ray.

The peak intensity ratio I (200) / I (111) of the face-centered cubic structure was determined by X-ray diffraction using a crystal orientation CuKα ₁ ray.

An AC magnetic permeability (μ) was measured in the direction of the hard axis by the S-parameter method using a network analyzer. Measurement frequency is 10MHz
And

In each table, fcc is face-centered cubic, bcc is body-centered cubic, and Hf-Co is Co ₂₃ Hf ₆ .

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051] As shown in the table, the soft magnetic alloy of the present invention has a predetermined composition, and the λs · Δd (111) / d 0 (111) is within the predetermined range, the high Bs It can be seen that a high permeability can be obtained at a high frequency at the same time, and that a low value of λs does not directly lead to a high permeability at a high frequency.

On the other hand, as shown in Tables 1 and 2, in the samples in which the added amount of Ti, Hf or Ti + Hf exceeds the limited range, the magnetic permeability at high frequency is low, and Bs
Is also low.

Comparative Sample Nos. 301 to 305 in Table 3
Are Fe ₂₉ described in JP-A-64-8605 described above.
Co ₄₀ Ni ₂₉ Ti ₂ thin film and main components (Fe, Co, Ni)
The samples have almost the same element ratio. In these comparative samples, since the main component composition is out of the limited range in the present invention, the magnetic permeability is rather lowered by the addition of Ti or Hf.

Comparative sample Nos. 306 to 310 in Table 3
Are Fe ₄₂ described in the above-mentioned JP-A-2-68906.
The sample has almost the same element ratio as Co ₁₈ Ni ₃₅ Ti ₄ and Fe ₄₃ Co ₁₉ Ni ₃₅ Hf ₃ . In these comparative samples, since the main component composition is out of the limited range in the present invention, the magnetic permeability is rather lowered by the addition of Ti or Hf.

Comparative sample Nos. 311 to 314 in Table 3
Also, since the main composition is out of the limited range in the present invention, the magnetic permeability is rather lowered by the addition of Ti or Hf.

Sample Nos. 316 and 318 in Table 3
Is that z representing the amount of Ni is out of the preferred range,
Compared with Sample Nos. 315 and 317, respectively, the improvement in characteristics due to the addition of Ti is observed.

A soft magnetic thin film having a thickness of 500 A and a thickness of 5
When a soft magnetic thin film was formed in the same manner as in each of the above samples in a multilayer film in which 20 non-magnetic insulating thin films (Si ₃ N ₄ ) of 0 A were alternately laminated, Ti and / or Alternatively, the effect of adding Hf was apparent.

The effects of the present invention are apparent from the results of the above examples.

[Brief description of the drawings]

FIG. 1 is a three-component composition diagram showing a ratio of a main component of a soft magnetic alloy of the present invention.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoshi Noguchi 1-1-13 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Taro Oike 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK (72) Inventor Osamu Shinoura 1-1-13 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (56) References JP-A-2-68906 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) C22C 38/00 303 C22C 19/07 C22C 38/14 H01F 1/14 H01F 10/16

Claims (3)

(57) [Claims] 1. The method according to claim 1, wherein Ti, and / or Ni are added to Fe, Co and Ni.
Or added Hf, atomic ratio of each element is represented by the formula _{(Fe x Co y Ni z)} 100-ab Ti a Hf b 0.10 ≦ x ≦ 0.55 in, 0.20 ≦ y ≦ 0.85, 0.05 ≦ z ≦ 0.28, 3x−5z ≦ 0.60, x + y + z = 1, 0 ≦ a ≦ 5, 0 ≦ b ≦ 3, 0.1 ≦ a + b ≦ 5 Saturation magnetostriction value is λs, the (111) face interval of face-centered cubic is d (111), and (111) of face-centered cubic when neither Ti nor Hf is included. ) The surface spacing is d ₀ (11
1), and when Δd (111) = d (111) −d ₀ (111), 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (111) ≦ 3.0 × 10 ^{− 8} is a soft magnetic alloy. 2. A soft magnetic thin film comprising the soft magnetic alloy according to claim 1. 3. A multilayer film wherein at least one layer is the soft magnetic thin film according to claim 2.