JPH07249519A - Soft magnetic alloy film, magnetic head, and method for adjusting coefficient of thermal expansion of soft magnetic alloy film - Google Patents

Abstract

PURPOSE:To reduce the difference in coefficient of thermal expansion between a soft magnetic alloy film and substrate so as to prevent the deterioration of the soft magnetic property of the alloy film by forming the solid solution of Ru in microcrystals composed mainly of Fe. CONSTITUTION:A soft magnetic alloy film is composed of microcrystals which is composed mainly of Fe and has a body-centered cubic structure and mean grain size of 40nm, the carbides or nitrides of one element or two or more elements selected from among Ti, Zr. Hf, V, Nb, Ta, Mo, and W deposited on the grain boundaries of the microcrystals, and the solid solution of either Si or A or Si and A and Ru formed in the microcrystals. Therefore, the influence of thermal stresses caused by heat treatment or gas welding on the alloy film can be reduced, because the difference in coefficient of thermal expansion between the alloy film and a substrate can be reduced by adjusting the coefficient of thermal expansion by changing the amount of Ru contained in the film. When this alloy film is used for a magnetic head, in addition, the soft magnetic property of the head can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic alloy film having excellent soft magnetic characteristics and a small thermal expansion coefficient, a magnetic head using the soft magnetic alloy film, and a method for adjusting the thermal expansion coefficient of the soft magnetic alloy film. It is a thing.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, a high performance magnetic head has been developed which is capable of increasing the coercive force of a recording medium in order to further increase the recording density and corresponding to this recording medium. In order to increase the magnetic recording density, it is preferable to make the track width and the gap length of the magnetic head as narrow as possible, and to reduce the coercive force while increasing the saturation magnetic flux density and the magnetic permeability. From such a viewpoint, a metal-in-gap type (MIG type) magnetic head in which a metal magnetic film is arranged in the vicinity of a magnetic gap of a magnetic core formed of ferrite or the like has been put into practical use.

A magnetic head called a laminated magnetic head has been developed in order to reduce the track width and increase the specific resistance to reduce the eddy current loss and improve the magnetic characteristics in the high frequency band. The laminated magnetic head is configured such that a soft magnetic alloy film is formed on a substrate by a film forming method such as sputtering or vapor deposition, the substrate is adhered again on the soft magnetic alloy film, and a magnetic core is sandwiched between the substrates. In this case, the thickness of the formed soft magnetic alloy film becomes the track width as it is. Therefore,
It is easy to narrow the track, and it is possible to improve the recording density and prevent interference with adjacent tracks. Also,
Since the magnetic circuit forming portion is a soft magnetic alloy film having a thickness of several μm, eddy current loss can be reduced and the performance of the magnetic head in the high frequency band can be improved.

[0004] The present inventors have found that a suitable軟軟magnetic alloy film on the MIG type magnetic head or a laminate type magnetic _{head, Fe Si a Al b M d} Z e T f becomes soft magnetic alloy film of the composition Has been developed and applied for a patent first.
In the composition formula, M is Ti, Zr, Hf,
V, Nb, Ta, Mo, W represents one or more elements, and Z represents one or two selected from C and N.
Indicates the element of the species, T is Cr, Ti, Mo, W, V, R
e, Ru, Rh, Ni, Co, Pd, Pt, Au, and one or more of them, and the composition ratios a, b, d, e and f are
8 ≦ a ≦ 15, 0.5 ≦ b ≦ 10, 1 ≦ d ≦ 10, 0.5
The relations ≦ e ≦ 15 and 0 ≦ f ≦ 10 are satisfied. A soft magnetic alloy film of this composition type, which is formed by a film forming method such as sputtering and is further subjected to heat treatment to deposit fine crystal grains of Fe on the order of several nm to several tens nm, has a high saturation magnetic flux density and is excellent. It has high permeability and low coercive force,
It has excellent soft magnetic properties and is extremely excellent for magnetic heads.

According to a recent study by the present inventors, the structure of the soft magnetic alloy film is such that fine crystal grains of Fe and carbides or nitrides of elements other than Fe precipitated at the grain boundaries of the fine crystal grains. It is known that the organization is mainly composed of.
Furthermore, recent research has also revealed that in the soft magnetic alloy film, in order to improve the soft magnetic properties, it is sufficient to reduce the number of non-magnetic particles such as carbides and nitrides existing at grain boundaries. In the soft magnetic alloy film having the composition, a film in which the concentration of the carbide of the element M (group IVA, group VA, group VIA of the periodic table) is minimized, for example, Fe-Si-Hf
-C-based, Fe-Si-Al-W-C-based films, etc., in which the content of the elements M and C is about 4 atomic% or less, the film containing more than 10 atomic% of the elements M and C is used. It has also been found that excellent soft magnetic properties can be obtained.

The reason why the soft magnetic characteristics are improved when the number of non-magnetic particles at the grain boundaries is reduced as described above is that the non-magnetic particles existing at the grain boundaries are present when the fine crystal grains of Fe, which are magnetic, are magnetically coupled to each other. Since it seems that this magnetic coupling is separated, the magnetic coupling between fine crystal grains of Fe is improved by reducing the number of non-magnetic particles existing at this grain boundary, and as a result, the soft magnetic characteristics are improved. I presume.

[0007]

By the way, in the soft magnetic alloy film in which the elements M and C are reduced as described above,
Although the film itself has excellent soft magnetic properties, it has a relatively small average thermal expansion coefficient (coefficient of linear expansion α) (α = 60 to 7).
Since the amount of 0 × 10 ⁻⁷ / degree) becomes small, there is a problem that the overall thermal expansion coefficient becomes high. For example, the elements M and C
In the case of a film in which the content of each is less than about 4 atomic%, α ≧ 140 × 1
Indicates ^0-7 . When the coefficient of thermal expansion of the soft magnetic alloy film is increased in this way, in the case of a laminated magnetic head or an MIG type magnetic head, the difference in thermal expansion from the magnetic core made of ferrite or ceramics, which is the base, becomes large, and There is a problem that thermal stress is likely to be applied during film processing or thermal processing, and the thermal stress deteriorates the soft magnetic characteristics of the soft magnetic alloy film.

By the way, a magnetic head for a hard disk of a computer, a magnetic head for audio, or
To manufacture a magnetic head for a video camera, usually, a soft magnetic alloy film, a non-magnetic layer, and a glass layer for welding are formed on a block-shaped substrate, which is bonded to another substrate and heated and pressure-bonded to each other. A large number of magnetic heads are manufactured from a pair of substrates by welding a pair of substrates that have been glass-welded and cut out in a direction perpendicular to the joint surface and polishing the substrates.
When carrying out such a manufacturing method, a magnetic base such as a ferrite base may be used as the base or a non-magnetic ceramic base may be used as the base depending on the structure of the target magnetic head. In addition, depending on the structure of the soft magnetic alloy film, a plurality of types of soft magnetic alloy film, an intermediate layer, an insulating layer, and the like may be laminated as necessary.

Therefore, when manufacturing this type of magnetic head, the glass welding step must be performed at a high temperature (for example, 600 to
It is heated to about 700 ° C.) and then cooled to room temperature. In this case, Mn-Zn ferrite, MnO-NiO ceramics, TiO ₂ -CaO ceramics, etc. are used for the base body of the magnetic head, and sendust, amorphous alloy, or fine crystal alloy is often used for the soft magnetic alloy film. However, since the materials of the base material and the soft magnetic alloy film have different thermal expansion coefficients as described above, thermal stress is likely to be applied during cooling and strain is likely to occur. In general, the material of the base often has a smaller coefficient of thermal expansion than the material forming the soft magnetic alloy film, and the soft magnetic alloy film shrinks more than the base, resulting in distortion of the soft magnetic alloy film. .

When such distortion occurs, the magnetic permeability of the magnetic core is likely to decrease and the coercive force is likely to increase, which is very inconvenient for a magnetic head. In addition, such deterioration of characteristics tends to occur naturally as long as the soft magnetic alloy film is formed on the substrate such as ceramics even when the soft magnetic alloy film is not held by the substrate like the MIG type magnetic head. It is in. Moreover, the influence of this strain occurs not only on the glass bonding interface but also on the interface with the substrate on which the soft magnetic alloy film is formed. Therefore, the problem of thermal distortion is an important problem not only in the laminated magnetic head but also in the MIG type magnetic head, the thin film magnetic head, and the like.

The present invention has been made to solve the above problems, and in a soft magnetic alloy film formed on a substrate and used for a magnetic head or the like, a thermal expansion coefficient difference between the soft magnetic alloy film and the substrate is reduced. To provide a soft magnetic alloy film which prevents addition of strain, has a high saturation magnetic flux density and magnetic permeability, and has excellent soft magnetic characteristics with a low coercive force, and a magnetic head using the same. It is another object of the present invention to provide a soft magnetic alloy film having excellent soft magnetic properties by adjusting the thermal expansion coefficient of the soft magnetic alloy film.

[0012]

In order to solve the above-mentioned problems, the present invention provides a fine crystal having a body-centered cubic structure containing Fe as a main component and having an average crystal grain size of 40 nm or less, Ti, Zr, H deposited on the grain boundaries of the fine crystals
f, V, Nb, Ta, Mo, W, or a carbide or nitride of one or more elements selected from the group consisting of at least Si and Al. One or two kinds and Ru form a solid solution.

In order to solve the above-mentioned problems, the invention according to claim 2 has the following composition formula in claim 1. Fe _100-abcde Si _a Al _b Ru _c M _d Z _e However, M is Ti, Zr, Hf, V, Nb, Ta, M
one or more elements selected from o and W, Z represents one or two elements selected from C and N, and the composition ratios a, b, c, d, and e are atomic% , 8 ≦ a ≦ 15, 0
≤b≤10, 0.5≤c≤15, 1≤d≤10, 1≤e
The relationship of ≦ 10 is satisfied.

In order to solve the above-mentioned problems, the invention according to claim 3 is a non-equilibrium state in which the fine crystals containing Fe as a main component according to claim 1 or 2 are produced by heat-treating an amorphous phase. R for the Fe crystal in the equilibrium state
Ru is dissolved in the fine crystals of Fe in an amount larger than the solid solution limit amount of u.

In order to solve the above-mentioned problems, the invention according to claim 4 is characterized in that, from the room temperature to 70
The coefficient of linear expansion up to 0 ° C. is 110 to 140 × 10 ⁻⁷ / degree.

In order to solve the above-mentioned problems, the present invention according to claim 5 provides the method according to claim 1, 2 or 3 from room temperature to 70%.
The coefficient of linear expansion up to 0 ° C. is 110 to 130 × 10 ⁻⁷ / degree.

In order to solve the above problems, the invention according to claim 6 uses the soft magnetic alloy film according to claim 1, 2, 3, 4 or 5 for a part or all of a magnetic core.

In order to solve the above-mentioned problems, the invention according to claim 7 is mainly composed of Fe fine crystals containing at least Ru as a solid solution, and Ti, Zr, Hf, V, Nb, and T are present in the grain boundaries.
A method for adjusting the thermal expansion coefficient of a soft magnetic alloy film, which comprises depositing carbides or nitrides of one or more elements selected from a, Mo, and W, wherein the formed amorphous phase is heat-treated. By doing so, fine crystals of Fe in a non-equilibrium state are deposited, and at this time, Ru which can form a solid solution in the Fe crystals in an equilibrium state is deposited.
More than the amount of Ru is solid-dissolved to adjust the coefficient of thermal expansion.

In order to solve the above-mentioned problems, the invention according to claim 8 adds Si and Al to the fine crystal of Fe according to claim 7.
Is further solid-dissolved.

In order to solve the above-mentioned problems, the invention according to claim 9 uses a soft magnetic alloy film according to claim 7 or 8 having the following composition formula. Fe _100-abcde Si _a Al _b Ru _c M _d Z _e However, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
At least one element selected from W, Z is C,
Representing at least one or more elements selected from N, the composition ratio a, b, c, d, e is atomic% and 8 ≦ a ≦ 15,0
≤b≤10, 0.5≤c≤15, 1≤d≤10, 1≤e
The relationship of ≦ 10 is satisfied.

[0021]

The present inventors have developed the previously developed Fe Si _a Al
_b M _d Z _e T _f becomes the soft magnetic alloy film of the composition results continued research, the fine crystals of the body-centered cubic fine structure of the soft magnetic alloy film composed mainly of Fe (bcc) structure, the grain It was found that non-magnetic particles such as carbides or nitrides of the element M dispersed in the boundary were the main constituents, and more than the amount allowed in equilibrium was dissolved in the Fe fine crystals. did. Further, in this composition system, the thermal expansion coefficient and the volume fraction of the carbide of the element M are fixed and both are small, so that it is an element that forms a solid solution with Fe fine crystals and the thermal expansion coefficient of the simple substance is small. Considering that the addition of elements is effective, we investigated the addition of various added elements,
It was found that the addition of Ru is extremely effective.

In this composition system, Ru can only form a solid solution in Fe crystals in the equilibrium state at about several atomic%, but Fe fine crystals produced by crystallization from the amorphous phase are
It is in a non-equilibrium state and can dissolve more Ru than the equilibrium Fe crystal. As a result, a large amount of R is added to the soft magnetic alloy film.
It becomes possible to contain u, and it becomes possible to adjust the coefficient of thermal expansion thereof, and by reducing the coefficient of thermal expansion, the difference in coefficient of thermal expansion from the base body when used for a magnetic head becomes small,
The influence of thermal stress associated with the heat treatment during heat treatment or glass welding is reduced, and the soft magnetic characteristics when used in a magnetic head are improved.

The coefficient of thermal expansion of the soft magnetic alloy film is required to reduce the difference with the substrate to prevent deterioration of the soft magnetic characteristics.
The range of 10 to 140 × 10 ^-7 / degree is preferable, and 110 to 10
The range of 130 × 10 ⁻⁷ / degree is more preferable. Further, the soft magnetic alloy film of the present invention can endure heat treatment at a higher temperature than a magnetic head using a soft magnetic alloy film which has been conventionally used. Therefore, since it withstands the glass welding process at a higher temperature, the range of choice of the fused glass is widened and the glass can be easily fused.

When a magnetic head is formed using the soft magnetic alloy film having the above composition, a magnetic head having a high saturation magnetic flux density, a high magnetic permeability, and a low coercive force and excellent soft magnetic characteristics can be obtained. Further, when manufacturing a magnetic head having a soft magnetic alloy film having the above structure or the above composition, the soft magnetic properties of the soft magnetic alloy film may be deteriorated even if a glass welding process or a heat treatment process is performed and heating to a high temperature is performed. That's not it.

The present invention will be described in more detail below. FIG. 1 shows an example of a magnetic head for a hard disk device formed by using a soft magnetic alloy film according to the present invention. Figure 1
The magnetic head 10 shown in FIG. 1 is composed of a slider 14 having levitation rails 16 formed therein, a core portion 18 formed at an end of one levitation rail 16 and a magnetic core 20. If the core 14 and the core portion 18 are bases, the magnetic core 20 is sandwiched between these bases.

FIG. 2 shows an enlargement of the portion A in FIG. A soft magnetic alloy film 20 'is sandwiched between a base 14' and a base 14 '' which are also a part of the slider 14, and a soft magnetic alloy film 20 'is also provided between the base 18' and a base 18 '' which is also a part of the core portion 18. The alloy film 20 ″ is sandwiched, and the magnetic core 20 is constituted by the soft magnetic alloy film 20 ′ and the soft magnetic alloy film 20 ″. Further, a non-magnetic layer is interposed between the slider 14 and the core portion 18. This constitutes a magnetic gap 22. Furthermore, the magnetic core 20 and the bases 14 '' and 18 '' are bonded between one surface of the magnetic core 20 and the bases 14 '' and 18 ''. The laminated glass 24 is interposed between the core portion 18 and the core portion 18. A coil is wound around the core portion 18 to form a magnetic head (not shown).

In the magnetic head 10, the soft magnetic alloy films 20 ′ and 20 ″ have a body-centered cubic structure containing Fe as a main component and fine crystals having an average crystal grain size of 40 nm or less.
Ti, Zr, Hf deposited on the grain boundaries of the fine crystals,
Vb, Nb, Ta, Mo, W, or a carbide or nitride of one or more elements selected from the group consisting of at least one or two of Si and Al, and Ru. Is formed from a soft magnetic alloy film formed by solid solution.

As the soft magnetic alloy film, one having the following composition formula is preferably used. Fe _100-abcde Si _a Al _b Ru _c M _d Z _e However, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
At least one element selected from W, Z is C,
Representing at least one or more elements selected from N, the composition ratio a, b, c, d, e is atomic% and 8 ≦ a ≦ 15,0
≤b≤10, 0.5≤c≤15, 1≤d≤10, 1≤e
The relationship of ≦ 10 is satisfied. Further, the fine crystals of Fe are produced by heat-treating an amorphous phase in the as-deposited state, and solidify Ru in an amount larger than the solid solution limit amount of Ru in equilibrium with Fe. It is preferable to use a melted product.

In the soft magnetic alloy film having the above composition, Fe is a main component and an element responsible for magnetism. The non-magnetic particles composed of the carbide or nitride of the element M are effective in suppressing the growth and coarsening of the crystal containing Fe as the main component and improving the heat resistance of the soft magnetic characteristics. In addition, it has an effect of making it easily amorphous during film formation such as sputtering. In order to obtain these effects, it is desirable that the addition amount be 1 atomic% or more, but if it exceeds 10 atomic%, the saturation magnetic flux density Bs will decrease, which is not preferable.

C or N combines with the element M to form a carbide or a nitride. Similarly, it also has the effect of making it easily amorphous during sputtering. It is preferable that the soft magnetic alloy film is amorphous after the sputtering because homogeneous fine crystals can be easily obtained in the subsequent heat treatment. In order to obtain these effects, the addition amount is preferably 1 atomic% or more, but if it exceeds 10 atomic%, the saturation magnetic flux density Bs is lowered, which is not preferable.

Addition of _Al has the effect of improving _Al : environment resistance. It has the effect of increasing the specific resistance by forming a solid solution with _Al : Fe crystals. _Al : has the effect of slowing the growth of crystal grains and lowering the crystalline magnetic anisotropy energy to maintain excellent soft magnetic properties up to high temperatures and raise the heat resistant temperature. The added amount of _Al is preferably 0.5 atomic% or more in order to exert the effect of _Al . However, if it exceeds 25 atom%, the magnetostriction λ _s becomes too large and the saturation magnetic flux density Bs also decreases, which is not preferable.

Si has the effect of reducing the magnetostriction λ _s that increases with the addition of _Si : Al. _Si : Has a function of easily amorphizing the soft magnetic alloy film during sputtering. Therefore, in order to make the soft magnetic alloy film amorphous easily, conventionally, a large amount of carbide or nitride was contained, but the content of carbide or nitride can be reduced. It is possible to suppress a decrease in the saturation magnetic flux density. _Si : Si is solid-dissolved in the Fe crystal and has the effect of increasing the specific resistance. _Si : It has the effects of slowing the growth of crystal grains and lowering the crystalline magnetic anisotropy energy to raise the heat resistant temperature of soft magnetic characteristics.

The amount of Si added is preferably 0.5 atomic% or more in order to exert the effects of _Si to _Si . However, if it exceeds 25 atom%, the saturation magnetic flux density Bs is lowered, which is not preferable. Further, if Si and Al are added together at the same time, the magnetostriction λs becomes 0.
It is more effective to obtain the effects of the present invention, since the environmental resistance can be improved while suppressing the increase to + 3.0 × 10 ⁻⁶ . _In order to exert the effect of _Si more effectively,
It is more preferable that Si is contained at 8 atomic% or more. Normally, up to 25 atomic% is acceptable, but since the effect of _Si becomes excessive and negative magnetostriction (amount of Al added is positive magnetostriction) may become large, Si is more preferably 15 atomic% or less. Is more preferable.

Ru is dissolved in a larger amount in the non-equilibrium Fe fine crystals produced by heat treatment from the amorphous phase than in the equilibrium Fe crystals. Moreover, since the linear expansion coefficient of Ru alone is as low as 96 × 10 ⁻⁷ / degree, it is suitable for reducing the thermal expansion coefficient of the soft magnetic alloy film. When the content of Ru is increased, the value of stress applied to the soft magnetic alloy film decreases. In the coercive force, the Ru content is small up to 15 atom%, but increases rapidly when it exceeds 15 atom%.
The upper limit of the u content is preferably 15 atom%. It should be noted that the saturation magnetic flux density hardly decreases even if the amount of Ru added increases. From the above, in the present invention, the Ru content is preferably 0.5 to 15 atom%.

Other unavoidable impurities such as H, O and S can be regarded as the same as the composition of the soft magnetic alloy of the present invention even if they are contained to the extent that the desired characteristics are not deteriorated. is there.

The linear expansion coefficient (coefficient of thermal expansion) of the soft magnetic alloy film from room temperature to 700 ° C. is 110 to 140 × 10.
^-7 / degree is preferred, and the coefficient of linear expansion from room temperature to 700 ° C is more preferably 110-130 x ^10-7 / degree. Further, the average crystal grain size of the soft magnetic alloy film is 4
It is preferably 0 nm or less. As long as the above range of the coefficient of thermal expansion is satisfied, the substrate may be MnO—NiO ceramics, T
For example, iO ₂ —CaO ceramics can be used. These substrates have an average coefficient of linear thermal expansion of 115 × 10 ^{−7 to} 145 × 10 ⁻⁷ / degree between room temperature and 700 ° C.

In order to manufacture the magnetic head having the structure shown in FIG. 1, as shown in FIG. 3, first, the soft magnetic alloy film 20 is formed on one side surface of the block-shaped substrate 26. Next, a laminated glass 24 is formed on the soft magnetic alloy film 20,
It is attached to the other base body 26 ', heated and pressure-bonded for welding. At this time, the laminated glass 24 is also formed on the bonding surface of the base body 26 ', if necessary. Then, after cooling to room temperature to solidify the laminated glass 24, this block is cut and subjected to various processes such as cutting and polishing to form a plurality of sliders and cores each having a predetermined shape. Further, the soft magnetic alloy film is subjected to heat treatment using the heat of the glass welding step, and the amorphous phase as formed is changed to a crystalline phase by the heat treatment to exhibit the desired soft magnetic characteristics. And In order to change the amorphous phase to the crystalline phase, it is not necessary to use the heat at the time of glass welding, and a dedicated heat treatment step may be separately performed.

Next, the separately formed slider and core are aligned so that the soft magnetic alloy films sandwiched between them are aligned, and the non-magnetic fused glass 21 is placed on the upper part of the winding hole. Fill and bond the magnetic gap. Thus, the magnetic head 10 shown in FIG. 1 is manufactured. In addition, when a soft magnetic alloy film is formed on a substrate, a plurality of soft magnetic alloy films and insulating layers such as SiO ₂ are alternately laminated to form the soft magnetic alloy film shown in FIG.
It is also possible to form a magnetic core 33 composed of a plurality of soft magnetic alloy films 32, 32 and insulating layers 34, 34 sandwiched between a pair of bases 28, 28 as shown in FIG. In FIG. 4, reference numeral 24 is a laminated glass that adheres the magnetic core 33 and the base body 28, and reference numeral 30 is a magnetic gap.

FIG. 5 shows another example of the magnetic head 36 provided with the soft magnetic alloy film according to the present invention. The magnetic head 36 of this example is an MIG type magnetic head having a structure in which a pair of half cores 38, 38 having a soft magnetic alloy film 44 formed on a Mn—Zn ferrite substrate are joined so as to form a magnetic gap 42. A coil 46 is wound around the winding hole 52, and the magnetic core halves 38, 38 on which the soft magnetic alloy film is formed.
Are welded with glass that fills the track width regulating groove 48.

[0040]

EXAMPLE A soft magnetic alloy film according to the present invention is in a state where carbides or nitrides of the element M are uniformly dispersed by heat treatment. Fe _71.2 Si _11.1 Al _2.3 Ru _7.5
Using an alloy film having a composition of Hf _3.3 C _4.6 as an example, X-ray diffraction patterns before and after the heat treatment were measured. Heat treatment is 6
It was kept at 80 ° C. for 20 minutes and then cooled to room temperature. The X-ray diffraction pattern was measured using a Co-Kα radiation source. The X-ray diffraction pattern before heat treatment is shown in FIG.
The X-ray diffraction pattern after the heat treatment is shown in FIG. From FIG. 7, it can be seen that the soft magnetic alloy film as formed has a broad halo pattern and is amorphous before the heat treatment.

Next, from FIG. 6, after the heat treatment, α-Fe
(Crystal mainly composed of Fe having a body-centered cubic structure) and HfC
The presence of (crystals of Hf carbide) can be confirmed. Moreover,
From the position of the α-Fe diffraction peak, S-
It can be seen that i and Al are in solid solution. Also, α-Fe
And the half-value width of each X-ray diffraction peak of HfC, the crystal grain size of α-Fe is 15 nm, and the crystal grain size of HfC is about 2 to 3 nm.
It can be seen that it is.

A sample in which a soft magnetic alloy applicable to the soft magnetic alloy film of the present invention is formed on a flat substrate 26 as shown in FIG. 3 and is adhered to the other substrate 26 'with a laminated glass 24. The magnetic permeability and the coercive force were measured to test the corrosion resistance. The substrates 26, 26 'used for the test have a thickness of 1 mm,
The thickness of the soft magnetic alloy film 20 was 5 μm, and the thickness of the laminated glass 24 was 0.5 μm. Bonding at 700 ℃ 20
The heating and pressing was performed for 1 minute. The soft magnetic alloy film is formed by using a high frequency bipolar sputtering method, the substrate is water-cooled, and the sputter target is a composite target in which Fe or an alloy target of Fe and graphite and pellets of various elements are arranged. Is used.

The sputtering conditions are as follows. Ultimate vacuum: 5 × 10 ^-7 Torr or less, input high frequency power density:
2.4 × 10 ⁴ W / m ² , Ar pressure: 5 mTorr. Further, the linear thermal expansion coefficient (αf) of the soft magnetic alloy is calculated by measuring the temperature dependence of the curvature rate of a film formed on a substrate whose physical properties are known in advance by using an optical sensor. . The linear thermal expansion coefficient (αs) of the substrate is measured by a thermomechanical analyzer (TMA). The saturation magnetostriction constant λs is evaluated by an optical lever method before sandwiching the soft magnetic alloy film between the substrates. The initial magnetic permeability μ is measured by the figure 8 coil method. The coercive force Hc is measured by a DC B-H loop tracer.

Fe _69.5 Si _12.0 Al _1.1 Ru _10.8 Hf _2.7
Αf measured using a sample obtained by forming a soft magnetic alloy film having a composition of C _{3.9 on} a substrate made of a TiO ₂ —Ca-based material
The value of was 117 × 10 ⁻⁷ / degree. Further, in this sample, αs of the substrate is 125 × 10 ⁻⁷ / degree, and λs of the film is
Was + 0.7 × 10 ⁻⁶ , μ at 1 MHz was 2300, and coercive force was 30 A / m. In addition, Fe _66.7 Si _12.4 Al
_0.8 Ru _11.3 Hf _3.8 C _5.0 Soft magnetic alloy film
The value of αf measured using a sample obtained by forming a film on a substrate made of an nO—NiO-based material was 116 × 10 ⁻⁷ / degree. Further, in this sample, the αs of the substrate is 135 ×
^10-7 / degree, [lambda] s of the film + 1.1 × 10 ^-6, the μ of 1 MHz 3600, a coercive force of 25A / m.

Next, Fe prepared by the same method as described above
_With respect to alloy film samples having a composition of _80-x Si ₁₂ Ru _x Hf ₃ C ₄ , the linear expansion coefficient of soft magnetic alloy film samples of various compositions prepared by changing the Ru concentration x was measured. The linear expansion coefficient is measured by the same method as the previous test, and is 100 to 700 ° C.
Was calculated. The result is shown in FIG. As is clear from the results shown in FIG. 8, it is clear that the linear expansion coefficient gradually decreases as the amount of Ru added increases. From this result, it is clear that the Ru content should be increased in order to reduce the linear expansion coefficient.

In the soft magnetic alloy film sample of the composition Fe _80-x Si ₁₂ Ru _x Hf ₃ C _{4 and} the soft magnetic alloy film sample of the composition Fe _75-x Si ₁₁ Ru _x Al ₃ Hf ₅ C ₆ , the Ru concentration was measured. The film stress of soft magnetic alloy film samples of various compositions prepared by changing x was measured. To measure the film stress, a film formed on a Mn-Zn ferrite substrate (coefficient of linear expansion α≈117 × 10 ⁻⁷ / degree) was subjected to heat treatment of heating at 680 ° C. for 20 minutes and cooling to room temperature. Later warpage was measured and calculated. The result is shown in FIG. In FIG. 9, a positive stress value indicates that a tensile stress is acting on the film, and a negative stress value indicates that a compressive stress is acting on the film. From the results shown in FIG. 9, the film stress decreases as the Ru concentration increases, and the film stress becomes a value close to 0 within the range of the Ru concentration of 10 to 15% by weight. From the results shown in FIG. 9, it has been clarified that the higher the Ru concentration with respect to the film stress is in the range of 15 atomic% or less, the smaller the film stress and the more suitable it is for a magnetic head.

A soft magnetic alloy film sample having a composition of Fe _80-x Si ₁₂ Ru _x Hf ₃ C ₄ and Fe _75-x Si ₁₁ Ru _x Al ₃ Hf ₅ C ₆
Saturation magnetic flux densities of soft magnetic alloy film samples of various compositions prepared by changing the Ru concentration x were measured. The result is shown in FIG. Figure 10
As is clear from the results shown in Table 1, the saturation magnetic flux density slightly decreases as the amount of Ru added increases, but the decrease rate is small, and even if the Ru content is 15 atomic%, the magnetic head It has been revealed that it has a sufficiently high saturation magnetic flux density for use.

A soft magnetic alloy film sample having a composition of Fe _80-x Si ₁₂ Ru _x Hf ₃ C ₄ and Fe _75-x Si ₁₁ Ru _x Al ₃ Hf ₅ C ₆
With respect to the soft magnetic alloy film samples having different compositions, the coercive force of the soft magnetic alloy film samples having various compositions prepared by changing the Ru concentration x was measured. The result is shown in FIG. As is clear from the results shown in FIG. 11, although the Ru content is sufficiently low in the range of 15 atomic% or less, the Ru content is 1 or less.
It has been revealed that the coercive force rapidly increases when the content exceeds 5 atomic%. This is probably due to the reason explained below.

FIG. 12 shows Fe _60.1 Si _11.8 Ru _17.1 Hf.
_It shows an X-ray diffraction pattern of a soft magnetic alloy film sample having a composition of _4.0 C _5.0 after heat treatment at 680 ° C. As is clear from these results, when the Ru content exceeds 15 atomic%, the Ru content is increased. Precipitation of compound crystals contained at a concentration is observed. In the equilibrium state, the solid solution amount of Ru in the Fe-Si crystal is 10 atomic% or less, but in the alloy system according to the present invention, as described above with reference to FIG. It has been found that Ru also forms a solid solution with Fe fine crystals. However, as is clear from the results shown in FIG. 12, it was clarified that a compound crystal containing Ru at a high concentration was precipitated at a Ru content of more than 15 atomic%, which had an effect to increase the coercive force. From this result, it was found that the upper limit of the Ru content in the soft magnetic alloy film according to the present invention is preferably 15 atom%.

In the magnetic head for a hard disk shown in FIG. 1, the solitary-wave reproduction output was measured with a magnetic head composed of a magnetic film and a substrate corresponding to this embodiment and a magnetic head not corresponding to this. The magnetic head used in the test is
TiO-CaO ceramics was used as the base material, the track width was 5.5 μm, the gap depth was 2 μm, and the coercive force Hc of the hard disk used for measurement was 160
The measurement was performed at 0 Oe, a peripheral speed of 8.84 m / s, and a flying height of the magnetic head of 80 nm. The results are shown in Table 1.

[0051]

[Table 1]

As is clear from the results shown in Table 1, the magnetic head using the soft magnetic alloy film according to the present invention has a coefficient of thermal expansion of the film as compared with the magnetic head using the soft magnetic alloy thin film of the comparative example. This is close to the coefficient of thermal expansion of the substrate, which reduces the stress applied to the film, resulting in an improvement in head output of 2.1 dB.

Using the soft magnetic alloy film according to the present invention, FIG.
In the video magnetic head for VTR shown in (1), the soft magnetic alloy film is arranged only in the part (part) near the gap of the magnetic core, and the other part of the magnetic core is made of Mn-Zn ferrite (α≈117).
X 10 ⁻⁷ / degree) was manufactured, and the frequency characteristic of self-recording / reproducing was measured. The self-recording output here is
It is a relative value standardized by the inductance. Table 2 shows the magnetic film and substrate of the magnetic head used in the test. The track width of the magnetic head is 23 μm and the gap depth is 20 μm.
The magnetic tape used in the test had a coercive force of 1500 O
and the relative speed between the magnetic head and the magnetic tape was 3.8 m / s. The result is shown in FIG.

[0054]

[Table 2]

As is clear from the results shown in FIG. 13, the output of the magnetic head of the present invention is 2-3 dB higher than that of the comparative magnetic head in any frequency range.

FIG. 14 shows Fe _71.2 Si _{11.1 according} to the present invention.
Microstructure photograph of a soft magnetic alloy film having a composition of Al _2.3 Ru _7.5 Hf _3.3 C _4.6 after heat treatment at 680 ° C. (magnification: 1,000,000 times)
FIG. As is clear from this schematic diagram, a state in which carbide particles (nonmagnetic particles) of about 2 to 3 mm are dispersed like black dots in the grain boundaries of fine crystals containing Fe as a main component and having a particle diameter of about 15 nm. It could be confirmed.

[0057]

As described above, according to the present invention, since Ru is solid-dissolved in fine crystals containing Fe as a main component, the inclusion of Ru having a small thermal expansion coefficient reduces the overall thermal expansion coefficient. This makes it possible to reduce the difference in the coefficient of thermal expansion from the substrate and reduce the strain due to the thermal stress during heat treatment or glass welding, and it is possible to obtain an excellent soft magnetic property. In the composition system according to the present invention, Ru can only form a solid solution with Fe crystals in an equilibrium state of about several atomic%, but the Fe fine crystals produced by crystallization from the amorphous phase are in a non-equilibrium state. , Equilibrium Fe
More Ru can be solid-solved than the crystals of. This enables the soft magnetic alloy film to contain a large amount of Ru,
The coefficient of thermal expansion can be adjusted.

In the composition of the soft magnetic alloy according to the present invention,
By setting the addition amounts of Si and Al in a special range, it is possible to obtain a soft magnetic alloy film that has a high saturation magnetic flux density and is likely to become amorphous at the time of film formation. A fine crystal can be obtained, and a larger amount of Ru can be dissolved in this fine crystal than the equilibrium Fe crystal. Therefore, the coefficient of thermal expansion can be adjusted. Ti, Z
By adding one or more of r, Hf, V, Nb, Ta, Mo, and W in a special amount, it is possible to precipitate non-magnetic carbide particles or nitride particles at the grain boundaries of Fe fine crystals. Due to the presence of the non-magnetic particles, coarsening of the crystal grains of the fine crystal phase containing Fe as a main component can be suppressed. Therefore, excellent soft magnetic properties can be exhibited. Further, the soft magnetic alloy film of the present invention suppresses the coarsening of the crystal containing Fe as a main component by the non-magnetic particles, and therefore, at a higher temperature than the magnetic head using the soft magnetic alloy film which has been used conventionally. Can withstand the heat treatment of. Therefore, it withstands the higher temperature glass welding process,
The range of choice of fused glass is expanded, and it becomes easier to fuse.

The coefficient of thermal expansion of the soft magnetic alloy film is required to reduce the difference from that of the substrate to prevent deterioration of the soft magnetic characteristics.
The range of 10 to 140 × 10 ^-7 / degree is preferable, and 110 to 10
The range of 130 × 10 ⁻⁷ / degree is more preferable.

If a magnetic head is formed by using a soft magnetic alloy film having the above composition, a high saturation magnetic flux density, a high magnetic permeability, and a high coercive force exhibiting excellent soft magnetic characteristics of the alloy film. The magnetic head of Further, when manufacturing a magnetic head having a soft magnetic alloy film having the above structure or the above composition, the soft magnetic properties of the soft magnetic alloy film may be deteriorated even if a glass welding process or a heat treatment process is performed and heating to a high temperature is performed. That's not it.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic head for a hard disk device.

FIG. 2 is an enlarged view of a portion A of the magnetic head shown in FIG.

3A and 3B are process diagrams showing a manufacturing process of the magnetic head.
FIG. 3A shows a state before joining the block-shaped substrates, and FIG. 3B shows a state after joining.

FIG. 4 is an enlarged view of a magnetic gap portion of a magnetic head of another example.

FIG. 5 is a perspective view of a video magnetic head for a VTR.

FIG. 6 is an X-ray diffraction pattern of the soft magnetic alloy of Example after heat treatment.

FIG. 7 is an X-ray diffraction pattern of a soft magnetic alloy of Example before heat treatment.

FIG. 8 is a diagram showing the relationship between the Ru content and the linear expansion coefficient of the soft magnetic alloy film according to the present invention.

FIG. 9 is a diagram showing a relationship between Ru content and film stress in the soft magnetic alloy film according to the present invention.

FIG. 10 is a diagram showing the relationship between the Ru content and the saturation magnetic flux density of the soft magnetic alloy film according to the present invention.

FIG. 11 is a diagram showing the relationship between the Ru content and the coercive force of the soft magnetic alloy film according to the present invention.

FIG. 12 is an X-ray diffraction pattern of a sample having a Ru content of more than 15 atomic%.

FIG. 13 is a diagram showing the relationship between self-reproducing output and frequency of a magnetic head using a soft magnetic alloy film according to the present invention.

FIG. 14 is a schematic diagram showing a crystal structure of a soft magnetic alloy film having a composition according to the present invention.

[Explanation of symbols]

 10 magnetic head 18 core part 20 magnetic core 20 'soft magnetic alloy film 20' 'soft magnetic alloy film 21 welded glass 22 magnetic gap 24 laminated glass 26, 28 substrate 30 magnetic gap 32 soft magnetic alloy film 36 magnetic head 44 soft magnetic alloy Film 42 magnetic gap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01F 41/22

Claims (9)

[Claims] 1. A fine crystal having a body-centered cubic structure containing Fe as a main component and having an average crystal grain size of 40 nm or less, and Ti, Zr, Hf, V, and Nb which are precipitated at grain boundaries of the fine crystal.
Ta, Mo, W containing one or more kinds of carbides or nitrides of elements, and at least one of Si and Al in the body-centered cubic structure or Al.
A soft magnetic alloy film comprising a solid solution of seed and Ru. 2. The soft magnetic alloy film according to claim 1, which has the following composition formula. Fe _100-abcde Si _a Al _b Ru _c M _d Z _e However, M is Ti, Zr, Hf, V, Nb, Ta, M
one or more elements selected from o and W, Z represents one or two elements selected from C and N, and the composition ratios a, b, c, d, and e are atomic% , 8 ≦ a ≦ 150 0 ≦ b ≦ 10 0.5 ≦ c ≦ 15 1 ≦ d ≦ 10 1 ≦ e ≦ 10. 3. The fine crystals containing Fe as the main component according to claim 1 or 2 are in a non-equilibrium state produced by heat-treating an amorphous phase, and Ru of the Fe crystal in the equilibrium state is used. A soft magnetic alloy film, characterized in that Ru is dissolved in fine crystals of Fe in an amount larger than the solid solution limit amount. 4. The coefficient of linear expansion from room temperature to 700 ° C.
The soft magnetic alloy film according to claim 1, 2 or 3, wherein the soft magnetic alloy film has a thickness of 110 to 140 × 10 ^-7 / degree. 5. The linear expansion coefficient from room temperature to 700 ° C.
The soft magnetic alloy film according to claim 1, 2 or 3, wherein the soft magnetic alloy film has a thickness of 110 to 130 × 10 ^-7 / degree. 6. A magnetic head, wherein the soft magnetic alloy film according to claim 1, 2, 3, 4 or 5 is used for a part or all of a magnetic core. 7. A fine crystal of Fe, which is a solid solution of at least Ru, is mainly used, and Ti and Z are contained in the grain boundaries of the fine crystal of Fe.
A method for adjusting a thermal expansion coefficient of a soft magnetic alloy film, which comprises depositing a carbide or a nitride of one or more elements selected from r, Hf, V, Nb, Ta, Mo and W, and forming the film. The non-equilibrium F by heating the formed amorphous phase
A soft magnetic alloy characterized by precipitating a fine crystal of e and dissolving a larger amount of Ru than the amount of Ru that can be dissolved in the fine crystal of Fe in an equilibrium state to adjust the thermal expansion coefficient. Method for adjusting coefficient of thermal expansion of film. 8. The fine crystal of Fe according to claim 7, wherein Si
And a solid solution of Al, and a method for adjusting the coefficient of thermal expansion of a soft magnetic alloy film. 9. A method of adjusting the coefficient of thermal expansion of a soft magnetic alloy film, wherein the soft magnetic alloy film according to claim 7 or 8 has the following composition formula. Fe _100-abcde Si _a Al _b Ru _c M _d Z _e However, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
At least one element selected from W, Z is C,
Representing at least one or more elements selected from N, the composition ratios a, b, c, d, and e are atomic%, and 8 ≦ a ≦ 150 ≦ b ≦ 10 0.5 ≦ c ≦ 151 ≦ d The relationship of ≦ 10 1 ≦ e ≦ 10 is satisfied.