JPH08104954A - Soft magnetic alloy, soft magnetic thin film and multilayer film - Google Patents

Abstract

PURPOSE: To obtain a soft magnetic alloy having high Bs and high magnetic permeability at high frequency by specifying a compsn. consisting of Fe, Co and Ni as essential components and Ti and Hf as additives and forming a face-centered cubic single phase having a specified saturation magnetostriction value. CONSTITUTION: This soft magnetic alloy is a soft magnetic Fe-Co-Ni alloy represented by the formula (Fex Coy Niz )100-a-b Tia Hfb (where 0.10<=x<=0.55, 0.20<=y<=0.85, 0.05<=z<=0.28, 3x-5z<=0.60, x+y+z=1, 0<=a<=5, 0<=b<=3 and 0.1<=a+b<=5) and the phase of this alloy is practically a face-centered cubic single phase. When the saturation magnetostriction value of the face-centered cubic phase is represented by λs, the (111) spacing of the phase is represented by d(111) and the (111) spacing of the phase in the case where neither Ti nor Hf is contained is represented by d0 (111), the relation of 1.0×10<-8> <=λs.Δd(111)/d0 (111)<=3.0×10<-8> [where Δd(111)=d(111)-d0 (111)] is satisfied. This alloy ensures high Bs and high magnetic permeability at high frequency especially as a thin film and the 1st layer of a multilayer film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION 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 come to be used with the 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, a soft magnetic thin film having a high saturation magnetic flux density (Bs) or a soft magnetic multilayer film・ Gap (MI
G) type magnetic heads, laminated type magnetic heads, thin film magnetic heads and the like have been used. The soft magnetic thin film and soft magnetic multilayer film used for these magnetic heads are required to have a high coercive force (Hc) and a low magnetic permeability (μ) in addition to a high Bs. Particularly 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 properties are not sufficient.

For example, as a system showing high Bs, a system containing Fe or Fe-Co alloy as a basic component is known. However, the Fe—Co alloy-based material has a large magnetostriction.
For this reason, even if the substrate temperature and the heat treatment temperature are optimized when the film is formed by the sputtering method, Hc becomes high and sufficient soft magnetic characteristics cannot be obtained.

As a technique for improving the soft magnetic properties of Fe-based materials, it has been proposed to add N and O to Fe by several percent or less (Japanese Patent Laid-Open No. 2-57665). This product has Bs of 15 kG or more and Hc of 1.5 O.
Although it is less than e and exhibits good soft magnetic properties, it has low corrosion resistance, and there is a problem that the magnetic properties are significantly deteriorated due to easy oxidation in an environment of normal temperature and normal humidity. Further, there is also a problem in heat resistance, and the heat that is inevitably applied when manufacturing the element causes deterioration of the characteristics.

Co = 50-60 wt%, Fe = 2 in 7 pF-15 of the 16th Japan Society for Applied Magnetics Academic Lectures
It has been reported that a plating film containing 0 to 30 wt% and Ni = 20 to 30 wt% can obtain high Bs of 19 kG or more and good corrosion resistance. However, this plated film has a magnetic permeability (μ) of about 600 to 700, which is lower than that of permalloy. Moreover, the measurement frequency of magnetic permeability is not described in the document.

In the ternary composition diagram of FIG. 1 of Japanese Patent Publication No. 63-53277, λ in the Fe--Co--Ni plating film is shown.
Although the s = 0 line is shown, the same publication does not measure magnetic permeability at high frequencies. It should be noted that Fe of high Bs described in the above-mentioned 16th Japan Society for Applied Magnetic Science abstracts
In the -Co-Ni plated film, it is considered that the magnetic permeability is low because the absolute value of λs is large.

[0008]

The object of the present invention is to provide Fe
-Co-Ni soft magnetic alloy, especially for thin films, high Bs
And to achieve high magnetic permeability at high frequencies.

[0009]

Such an object is achieved by any of the following constitutions (1) to (3).
(1) Fe, Co as a main component and Ni, wherein the Ti and / or Hf as an additive, the atomic ratio of each element is represented by the formula _{(Fe x Co y Ni z)} 0 in _100-ab Ti _a Hf _b. 10 ≦ x ≦ 0.55, 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, which is substantially composed of a face-centered cubic single phase, the saturation magnetostriction value is λs, and the face-centered cubic (111) spacing is d (111). , (111) face spacing of the face-centered cubic crystal when none of Ti, H and Hf is contained is d ₀ (111)
Then, when Δd (111) = d (111) −d ₀ (111), 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (11
1) Soft magnetic alloy with ≦ 3.0 × 10 ⁻⁸ . (2) A soft magnetic thin film composed of the soft magnetic alloy of (1) above. (3) A multilayer film in which at least one layer is the soft magnetic thin film described in (2) above.

[0010]

In the present invention, Fe-Co-Ni-based soft magnetic alloys, particularly Fe and Co, which are the main compositions in thin films, are used.
And Ni and / or Hf are added, and λs · Δd (111) / d ₀ (11
1) exists within a predetermined range. The addition of Ti or Hf makes the crystal grains finer, and the magnetostriction and the lattice spacing change. In the present invention, Ti and Hf are added in a predetermined amount and the composition ratio of Fe, Co and Ni is set in a predetermined range, whereby the refinement of crystal grains and the magnetoelastic effect act synergistically, resulting in excellent softness. Magnetic characteristics, especially high permeability at a high frequency of about 10 MHz can be obtained. The magnetoelastic effect is caused by magnetostriction and internal stress due to strain of the lattice. Moreover, in addition to excellent soft magnetic properties, heat resistance that can withstand heat treatment at 500 ° C. is obtained, and high saturation magnetization of 15 kG or more can be obtained.

Conventionally, in Fe-Co-Ni type alloys,
It is difficult to achieve both high Bs and high magnetic permeability, and no proposal has been made to realize high magnetic permeability especially at high frequencies. However, according to the present invention, high magnetic permeability at high frequency is obtained even in the composition range where high Bs is obtained. Has come to be obtained.

Table 1 of JP-A-2-68906 shows
Fe ₄₂ Co ₁₈ Ni ₃₅ T formed by the sputter deposition method
i ₄ and Fe ₄₃ Co ₁₉ Ni ₃₅ Hf ₃ are 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 outside the range defined by the present invention, λs · Δd (111) / d ₀ (111) does not fall within the range defined by the present invention, and is naturally equivalent to the present invention. The effect of is not realized. The publication only describes the initial magnetic permeability, and does not pay attention to the magnetic permeability at a high frequency of about 10 MHz.

Further, Japanese Patent Application Laid-Open No. 64-8605 discloses that
There is described 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. Fe ₂₉ C
o ₄₀ Ni ₂₉ Ti ₂ thin film is made of Fe-Co-Ni alloy with Ti.
Is similar to the present invention in that the addition of Fe, Co, N
Since the ratio of i is out of the range limited by the present invention,
The same effect as the present invention cannot be realized. In the same publication, 10 MH
No attention is paid to the permeability at high frequencies around z.

[0014]

Specific Structure The specific structure of the present invention will be described in detail below.

The soft magnetic alloy of the present invention contains Fe, Co and Ni as main components, and Ti and / or H as additives.
Including 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, and 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 a limited range of x, y, and z representing atomic ratios of Fe, Co, and Ni. Specifically, when 3x-5z> 0.60, body-centered cubic crystals tend to precipitate. If z is too small, body-centered cubic crystals are likely to precipitate. Also, if z is too large, high Bs
Can not be obtained. If x is too small, hexagonal close-packed crystals will be precipitated and a face-centered cubic structure will not be obtained. On the other hand, if a + b is too small, the effect of adding Ti or Hf becomes insufficient, and high permeability cannot be obtained at high frequencies. If at least one of a, b, and a + b is too large, body-centered cubic crystals or Hf-Co or other compound phase precipitates.
High permeability cannot be obtained at high frequencies.

In order to improve corrosion resistance and wear resistance, part of Fe is 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 the decrease of Bs, the content of these elements is preferably 3% by weight or less.

The soft magnetic alloy of the present invention is substantially composed of a face-centered cubic single phase. If the body-centered cubic single phase or a mixed crystal of face-centered cubic and body-centered cubic phases is obtained, 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, Therefore, it is possible that high characteristics are obtained. Therefore, the "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. 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. By adding Ti or Hf, the crystal grains are made finer in this way, so that 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 face-centered cubic (111) spacing is d (111)
Then, 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 face-centered cubic (111) spacing when the ratios of Fe, Co, and Ni are the same and neither Ti nor Hf is contained. The soft magnetic alloy of the present invention is substantially composed of face-centered cubic crystals,
1) The plane is preferentially oriented. Since the magnetoelastic effect contributes to the soft magnetic characteristic, in the present invention, λs · Δd (111) / d _{0 is} used as an index for estimating the contribution due to the magnetoelastic effect.
(111) was defined, and the correlation with the soft magnetic characteristics, particularly the magnetic permeability at high frequencies, was investigated. It was also found that in the above range, a high magnetic permeability at a high frequency, for example, a magnetic permeability of 500 or more at 10 MHz can be obtained. Note that d (111) is Cu
In X-ray diffraction using the Kα ₁ line, the face-centered cubic (1
It can be calculated from the diffraction angle 2θ of the 11) plane.

The soft magnetic alloy of the present invention is usually I (200) and I (111) when the peak intensity of the (200) plane and the peak intensity of the (111) plane in X-ray diffraction are I (200) and I (111), respectively. ) / I (111) ≦ 0.4. In the case of face-centered cubic crystal, the (111) plane is preferentially oriented. Since magnetostriction depends on the crystal orientation, for example, Japanese Patent Application No. 5-
In No. 166406, the composition and production 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 λs. Therefore,
It is not necessary to strictly control I (200) / I (111) for the purpose of reducing λs, and the productivity is good.

Next, a method for manufacturing 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 shape, a ribbon shape, and a plate shape according to the application.

For the production of a thin film soft magnetic alloy, a method of forming a thin film in a vapor phase such as a sputtering method, a vapor deposition method, an ion plating method, a CVD method or a liquid method such as an electroplating method is used. 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, an alloy casting or sintered body may be used as the target, and a composite target may be used. A bias sputtering method may be used to control the crystal orientation. Bias voltage is -30 to-
It is preferably 200V.

When the vapor deposition method is used, the substrate temperature is set to 40.
It is preferably 0 ° C. or lower.

Since the thin film formed by the sputtering method or the vapor deposition method has an internal stress, which makes it difficult to obtain a good soft magnetic property, it is preferable to perform a heat treatment for relaxing the stress after the film is formed. This heat treatment is preferably performed in vacuum or in an inert gas atmosphere, the holding temperature is preferably 300 to 700 ° C., and the treatment time is 1
It is preferably set to 2 hours.

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

It is preferable to impart uniaxial anisotropy to the intended direction in the thin film of the soft magnetic alloy. As a method for imparting uniaxial anisotropy, film formation in a magnetic field or magnetic field annealing after film formation can be used.

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

The thickness of the soft magnetic thin film formed by each of the above-mentioned methods may be appropriately determined depending on the purpose and is not particularly limited. However, in order to obtain a low coercive force, it is usually 0.
It is preferably about 5 to 10 μm, 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 also 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 less loss can be realized.

A liquid quenching method is preferably used for producing the ribbon-shaped soft magnetic alloy. In the liquid quenching method, a molten alloy is injected and brought into contact with the surface of a cooling substrate such as a chill roll to be rapidly cooled to produce a ribbon-shaped soft magnetic alloy. The liquid quenching method includes a single roll method for cooling the molten alloy from one direction,
There is a twin roll method that cools from two opposite directions,
In the present invention, it is preferable to use the single roll method. In order to produce the above-mentioned soft magnetic alloy with crystal orientation, various conditions such as the cooling rate of the molten alloy and the thickness of the ribbon may be appropriately selected. Although the preferable range of each of these conditions varies depending on the alloy composition, for example, the cooling rate is generally 1 × 10 ³ to
1 × 10 ⁶ K / s, particularly 1 × 10 ⁴ to 1 × 10 ⁶ K / s is preferable, and the thickness of the ribbon is generally 3 to 100 μm.
And particularly preferably 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 thin film soft magnetic alloy is, for example, MIG.
Type, laminated type, thin film type induction type magnetic head, magnetic resistance film of magnetoresistive effect type magnetic head, magnetoresistive effect film, thin film transformer, etc., and ribbon-shaped soft magnetic alloy is, for example, a choke coil, a transformer. The soft magnetic alloy formed into a plate shape by a casting method is applied to, for example, a magnetic shield plate, but the soft magnetic alloy of the present invention is also applicable to various magnetic devices other than these. It is possible.

[0035]

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

A soft magnetic thin film was formed on a glass slide (made by MATSUNAMI) substrate by the RF magnetron sputtering method to prepare a measurement sample.

The target is 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
The pressure during film formation is 10 × 10 ⁻³ Torr or less, the RF power is 200 to 400 W, and the film formation rate is 40 to 150 A / s.
The film thickness was about 5000 A. The substrate was not particularly cooled during sputtering.

After the film is formed, in order to relieve 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 carried out for each sample. The results are shown in each table.

Film composition was measured by fluorescent X-ray analysis.

Saturation magnetic flux density (Bs), coercive force (Hc) Using VSM (sample vibrating magnetometer), maximum applied magnetic field 10
Measured in kOe.

Saturation magnetostriction value (λs) A sample was placed in a magnetic field of 100 Oe rotating in the film plane, and expansion and contraction due to magnetostriction of the sample was detected as a warp by a synchronous rectification method using a laser beam to calculate λs did. The sample for measuring the saturation magnetostriction value had a thickness of 0.
A 15 mm glass plate was used as the substrate.

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

The average grain size was determined from the half-value 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 crystallographically oriented CuKα ₁ ray.

The AC 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 crystal, bcc is body-centered cubic crystal, and Hf-Co is Co ₂₃ Hf ₆ .

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

As shown in each table, in the soft magnetic alloy of the present invention having a predetermined composition and having λsΔd (111) / d ₀ (111) within a predetermined range, high Bs is high. It is found that a high magnetic permeability is obtained at the same time as the high frequency, and it is also understood that the low λs is not directly connected to the high magnetic permeability at the high frequency.

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

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

Comparative sample Nos. 306 to 310 in Table 3
Is Fe ₄₂ described in the above-mentioned JP-A-2-68906.
It is a sample in which the element ratios of main components are almost the same as those of Co ₁₈ Ni ₃₅ Ti ₄ and Fe ₄₃ Co ₁₉ Ni ₃₅ Hf ₃ . In these comparative samples, the composition of the main component is out of the limited range of the present invention, and therefore the permeability is lowered by the addition of Ti or Hf.

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

Sample Nos. 316 and 318 of Table 3
Is outside the preferable range of z, which represents the amount of Ni,
When compared with Sample Nos. 315 and 317, respectively, the characteristic improvement by the addition of Ti is recognized.

A soft magnetic thin film with a thickness of 500 A and a thickness of 5
When a soft magnetic thin film was formed in the same manner as 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 Hf addition was clear.

From the results of the above examples, the effects of the present invention are clear.

[Brief description of drawings]

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

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01F 10/16 (72) Inventor Kiyoshi Noguchi 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK stock Inside the company (72) Inventor Taro Oike 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Inventor Osamu Shinoura 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation

Claims (3)

[Claims] [Claim 1] Fe, Co as a main component and Ni, wherein the Ti and / or Hf as an additive, the atomic ratio of each element is represented by the formula (Fe _x Co _y Ni _z) in _100-ab Ti _a Hf _b 0.10≤x≤0.55, 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, substantially composed of a face-centered cubic single phase, a saturation magnetostriction value of λs, and a face-centered cubic (111) spacing of d (111). ) And the (111) spacing of face-centered cubic crystals when neither Ti nor Hf is contained is d ₀ (11
1) and Δd (111) = d (111) −d ₀ (111), 1.0 × 10 ⁻⁸ ≦ λs · Δd (111) / d ₀ (11
1) Soft magnetic alloy with ≦ 3.0 × 10 ⁻⁸ . 2. A soft magnetic thin film composed of the soft magnetic alloy of claim 1. 3. A multilayer film in which at least one layer is the soft magnetic thin film according to claim 2.