JP2710441B2 - Soft magnetic laminated film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a soft magnetic laminated film having a high saturation magnetic flux density suitable for a magnetic head or the like.

[Prior Art] In the field of magnetic recording, a recording medium such as a magnetic tape has been promoted to have a high coercive force in order to increase a recording density. However, as a material of a magnetic head corresponding thereto, a saturation magnetic flux density (Bs) is required. High things are required.

As a conventional soft magnetic material (film) with a high saturation magnetic flux density, Fe
A typical example is a -Si-Al alloy (Sendust). In recent years, an amorphous alloy film mainly composed of Co, which is a ferromagnetic metal element, has been developed.

Further, as a recent attempt, the influence of the magnetocrystalline anisotropy of Fe (the adverse effect on soft magnetism) has been reduced by using an alloy film (Fe-C, Fe-Si, etc.) composed of fine crystals containing Fe as the main component. In some cases, a film having a high saturation magnetic flux density and excellent soft magnetic properties is obtained.

[Problems to be Solved by the Invention] By the way, devices incorporating a magnetic head tend to be reduced in size and weight, and are subject to vibration accompanying movement,
It is increasingly used in adverse environments. Therefore, the magnetic head has excellent magnetic properties and, of course, excellent wear resistance to the magnetic tape,
It is required to have high durability in a humidity or corrosive atmosphere, that is, high environmental resistance, vibration resistance, and the like. For this reason, it is necessary to perform the gap formation, the incorporation into the case, and the like by glass welding, and the material of the magnetic head needs to be able to withstand the high temperature of the glass welding step in the head manufacturing process.

However, among the conventional soft magnetic alloy films, those made of sendust have a saturation magnetic flux density of about 10,000 G (Gauss), which is insufficient for a demand for higher density in the future. In addition, Co-based amorphous alloy films
Although high saturation magnetic flux density of more than 13000G has been obtained, when trying to increase the saturation magnetic flux density of conventional amorphous alloys, the amorphous forming elements Ti, Zr, Hf, Nb,
It is necessary to reduce the addition amount of Ta, Mo, W, etc., but if the addition amount is reduced, the stability of the amorphous structure decreases,
There is a problem that it cannot withstand the temperature required for glass welding (about 500 ° C. or higher).

Furthermore, the alloy film (Fe-C, Fe-Si, etc.) composed of fine crystals containing Fe as a main component causes crystal growth at a high temperature,
Soft magnetic properties deteriorate (400 ° C is the highest for Fe-C)
Therefore, it is hard to say that it is suitable for glass welding.

Against this background, the present inventors have filed Japanese Patent Application No. 1-278220.
Patents have filed a patent application for a soft magnetic alloy film that solves the above problem.

One of the soft magnetic alloy films for which a patent application is filed in Japanese Patent Application No. 1-278220 is a composition formula represented by FexMzCw, wherein the composition ratio x is 50 to 96 in atomic%, z is 2 to 30, w is 0.5 to 25,
The relationship x + z + w = 100 was satisfied.

In another one, the composition formula is represented by FexTyMzCw,
The composition ratio x is 50 to 96 in atomic%, y is 0.1 to 10, z is 2 to 3
0 and w satisfied the relationship of 0.5 to 25 and x + y + z + w = 100.

The soft magnetic alloy film provided in this patent application has a high saturation magnetic flux density of about 18000G in some compositions, high thermal stability compared to various conventional materials, sufficient corrosion resistance and environmental resistance It was what had. However, with this soft magnetic alloy film, a film having a saturation magnetic flux density of about 20,000 G cannot be obtained, and there is a problem that it cannot be used for a magnetic head that requires particularly high recording characteristics.

The present invention solves the above-mentioned problems, and has excellent soft magnetic properties,
The soft magnetic laminated film whose characteristics are thermally stable, high reliability glass welding can be performed, high saturation magnetic flux density of around 20,000G can be obtained, and sufficiently high magnetic characteristics can be obtained even without magnetic field heat treatment. It is intended to provide.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the invention described in claim 1 is configured such that a soft magnetic alloy film represented by a composition formula of FexMzCw and an Fe layer are alternately laminated, and The magnetic alloy layer is entirely formed of fine crystal grains having an average grain size of 0.08 μm or less, and includes a crystal phase of a carbide of the element M in a part of the fine crystal grains. Where M is Ti, Z
Among r, Hf, V, Nb, Ta, Mo, and W, a metal element composed of at least one kind or a mixture thereof, and the composition ratio x, z, w is 5% by atomic%
0 ≦ x ≦ 96, 2 ≦ z ≦ 30, 0.5 ≦ w ≦ 25, x + z + w = 10
It is assumed that the relationship of 0 is satisfied.

In order to solve the above-mentioned problem, the invention described in claim 2 includes a soft magnetic alloy layer represented by a composition formula of FexTyMzCw and Fe
The soft magnetic alloy layer is composed of fine crystal grains having an average grain size of 0.08 μm or less as a whole, and includes a crystal phase of a carbide of the element M in a part of the fine crystal grains. However, in the above composition formula, M is Ti, Zr, Hf, V, Nb, T
a, Mo, W, at least one metal element or a mixture thereof, T represents at least one of Co, Ni,
The composition ratios x, y, z, and w are expressed in atomic% as 50 ≦ x ≦ 96, 0.1 ≦ y ≦ 20, 2
It is assumed that the following relationship is satisfied: ≦ z ≦ 30, 0.5 ≦ w ≦ 25, and x + z + w = 100.

According to a third aspect of the present invention, in order to solve the above-mentioned problem, the soft magnetic alloy layer according to the first or second aspect includes a mixture of fine crystal grains having an average crystal grain size of 0.08 μm or less and an amorphous phase. It has a structure and includes a crystal phase of a carbide of the element M in a part of fine crystal grains.

According to a fourth aspect of the present invention, in order to solve the above-described problem, a concentration gradient of constituent elements of the soft magnetic alloy layer is provided at an interface between the Fe layer and the soft magnetic alloy layer according to the first, second, or third aspect. It is.

 Hereinafter, the present invention will be described in more detail.

FIG. 1 shows an embodiment of a soft magnetic laminated film according to the present invention. A laminated film 1 of this embodiment comprises a substrate 2, a Fe layer 3 made of pure iron, and a Fe-MC system. Alternatively, it is formed by alternately laminating Fe-TNC-based soft magnetic alloy layers 4.
In the laminated film 1, the soft magnetic alloy film 4
Are formed. The concentration distribution in the thickness direction of the laminated film 1 is as shown in FIG.

An example of the soft magnetic alloy layer 4 is represented by a composition formula of FexMzCw, and is entirely composed of fine crystal grains having an average particle size of 0.08 μm or less, and includes a crystal phase of a carbide of the element M in a part of the fine crystal grains. It is a thing. Where M is Ti, Zr,
Among Hf, V, Nb, Ta, Mo, and W, a metal element or a mixture of at least one of them, and the composition ratio x, z, w is 50 atomic%.
≦ x ≦ 96, 2 ≦ z ≦ 30, 0.5 ≦ w ≦ 25, x + z + w = 100
Satisfies the following relationship:

Another example of the soft magnetic alloy layer 4 is FexTyM
It is represented by a composition formula of zCw, which is composed entirely of fine crystal grains having an average particle diameter of 0.08 μm or less, and includes a crystal phase of a carbide of the element M in a part of the fine crystal grains. In the above formula, M represents at least one metal element or a mixture thereof among Ti, Zr, Hf, V, Nb, Ta, Mo, and W, and T represents at least one of Co and Ni. , Composition ratio x, y, z, w is atomic%
50 ≦ x ≦ 96, 0.1 ≦ y ≦ 20, 2 ≦ z ≦ 30, 0.5 ≦ w ≦ 2
5. It is assumed that the relationship x + z + w = 100 is satisfied.

As a method of forming the soft magnetic laminated film, the soft magnetic laminated film is formed by a thin film forming apparatus such as sputtering and vapor deposition. As the sputtering device, existing devices such as RF bipolar sputtering, DC sputtering, magnetron sputtering, tripolar sputtering, ion beam sputtering, and facing target type sputtering can be used, but two or more sputtering systems can be used in the same vacuum chamber. It is preferable to use an apparatus that can mount a target and can form a multilayer film without breaking a vacuum.

FIG. 3 shows an example of a film forming apparatus suitable for use in manufacturing the laminated film 1. In FIG. 3, reference numeral 5 denotes a substrate holder rotatably supported by a support shaft 6, and 7, 8 denote substrate holders.
, A partition 9 is provided between the cathodes 7 and 8, and the entire apparatus is housed in a vacuum vessel (not shown). A substrate 10 is provided on the upper surface of the substrate holder 5, a target 11 made of pure iron is provided on a lower surface of the cathode 7, and a pellet 12 such as a graphite plate and an element M such as Hf are provided on a lower surface of the cathode 8. And a target 14 made of pure iron and provided with a pellet 13 made of.

In order to form the laminated film 1 by the apparatus having the above-described configuration, sputtering is performed on both the cathodes 7 and 8 to generate sputter particles from each target, and the substrate 10 is rotated by 180 ° at predetermined time intervals to rotate the substrate 10. By alternately moving the lower side of the cathode 7 and the lower side of the cathode 8 alternately.

By the above operation, the Fe layer 3 is formed on the substrate 10 by the particles sputtered from the cathode 7, and the soft magnetic alloy layer 4 is formed by the particles sputtered from the cathode 8. Laminated film 1 shown
Is formed.

When the laminated film 1 having a predetermined thickness is formed on the substrate 1 by alternately rotating the substrate holder 5, the film forming operation is stopped.

Each soft magnetic alloy layer [Fe- (T) -MC film] in the laminated film 1 as produced in this way exhibits a certain soft magnetic property, but these soft magnetic alloy films have an amorphous phase. It contains a considerable proportion, and the saturation magnetic flux density is not high enough, the soft magnetic properties are not enough, and it is unstable. Precipitate. By performing this heat treatment in a static magnetic field or a rotating magnetic field, excellent soft magnetic characteristics can be obtained. Further, this heat treatment can be performed also as a glass welding step in the manufacturing process of the magnetic head.

The step of depositing the fine crystals does not need to be performed completely, and a considerable number of fine crystals (preferably 50% or more)
As long as it is deposited, the amorphous component may remain partially, and the remaining amorphous component does not hinder the improvement of the characteristics.

As a method for adding C into the film, as described above, in addition to the method of arranging graphite pellets 12 on a target plate to form a composite target and sputtering it,
(Fe-M or Fe-T-M)
And a reactive sputtering method or the like in which sputtering is performed in a gas atmosphere in which a hydrocarbon gas such as methane (CH ₄ ) is mixed in an inert gas such as Ar. In this reactive sputtering method, it is easy to control the C concentration in the film, but when forming the Fe layer 3, it is necessary to stop the supply of the CH ₄ gas before forming the film.

Hereinafter, the reason for limiting the components of the soft magnetic alloy layer 4 will be described. The reasons for limiting the components of Fe, element T, elements M and C are substantially the same as in Japanese Patent Application No. 1-278220.

Fe is a main component and is an element bearing magnetism. In order to obtain a saturation magnetic flux density of at least ferrite (Bs 5000G) or more, x ≧ 50% is required. Further, in order to obtain good soft magnetic characteristics, x ≦ 96% must be satisfied.

The element T (that is, Co, Ni) is an element added for the purpose of adjusting magnetostriction. In the case of the Fe-MC film, when the heat treatment temperature is low, the magnetostriction becomes positive, and when the heat treatment temperature is high, the magnetostriction becomes negative. When a high heat treatment temperature (glass welding temperature) is required, the magnetostriction can be made almost zero by adding an appropriate amount of Ni and Co, which have the effect of making the magnetostriction positive. When the heat treatment temperature is appropriate, the addition of element T is not particularly necessary, but the addition of T must adjust the value of y so that the positive magnetostriction does not increase to the order of +10 ^-5 or more. Where y
In the Japanese Patent Application No. 1-278220, 0.1 ≦ y
≦ 10 is expanded to 0.1 ≦ y ≦ 20 in the present invention because the magnetostriction of the Fe layer 3 is negative and large, so that the entire magnetostriction of the laminated film 1 is +10 ^−5. This is because the allowable amount of y for not increasing the size to the stage increases.

Element M is necessary for improving soft magnetic properties,
Further, it combines with C to form carbide fine crystals. In order to maintain good soft magnetic characteristics, it is necessary to satisfy z ≧ 2%. However, if the amount is too large, the saturation magnetic flux density decreases. Therefore, it is necessary to satisfy z ≦ 30%.

C is necessary for improving soft magnetic properties and improving heat resistance, and combines with C and the element M to form carbide fine crystals. In order to maintain good soft magnetic properties and thermal stability, it is necessary that w ≧ 0.5%. However, if it is too large, the saturation magnetic flux density decreases. There is.

The fine crystals of the carbide of the element M act as pinning sites for the domain wall, have the function of improving the high-frequency characteristics of magnetic permeability, and are dispersed uniformly in the film, so that the fine crystals of Fe grow by heat treatment and become soft magnetic. It has the function of preventing damage. In other words, when the Fe crystal grains grow and become large, the adverse effect of the magnetocrystalline anisotropy increases and the soft magnetic properties deteriorate, but the fine crystals of the carbide of the element M act as barriers for the Fe grain growth. Prevent deterioration of magnetic properties.

In the soft magnetic alloy layer 4, the composition is mainly composed of fine crystals rich in Fe, and the addition of a component for lowering the saturation magnetic flux density is restricted.
Since the magnetic moment and Curie temperature per unit are high, a high saturation magnetic flux density can be obtained. The element M
And C, and the metal structure is basically 0.
Since it is composed of fine crystal grains of not more than 08 μm and the adverse effect on soft magnetism due to crystal magnetic anisotropy is reduced, good soft magnetic properties can be obtained. Further, since the carbide of the element M precipitates to suppress the growth of crystal grains containing Fe as a main component, the crystal grains do not become coarse even when heated in the glass welding step.

In the laminated film 1 manufactured as described above, since the Fe layer 3 having a saturation magnetic flux density of 21.5 kG and the soft magnetic alloy film 1 having a maximum saturation magnetic flux density of 18 kG are alternately laminated, Thus, an extremely high saturation magnetic flux density exceeding 20,000 G can be obtained. Further, the Fe- (T) -MC soft magnetic alloy layer 4
Is that the film itself is mainly composed of fine crystals and has excellent soft magnetic properties, and the crystal grains in the Fe layer 3 are hardly grown in the film thickness direction by being sandwiched between the soft magnetic alloy layers 4 and 4 from above and below. So Fe
Since the crystal grains of the layer 3 are also fine and the soft magnetic properties of the Fe layer 3 are good, the laminated film 1 has excellent hard magnetic properties.

In order to improve the soft magnetic properties of the Fe layer 3, it is preferable that the thickness of one Fe layer 3 be 2000 mm or less. The thickness of the soft magnetic alloy layer 4 is not particularly limited. However, if the thickness is too large with respect to the Fe layer 3, it is difficult to obtain a high saturation magnetic flux density. If the thickness is too small, the concentration of each component is almost uniformly mixed in the film thickness direction due to atomic diffusion between the two layers due to the heat treatment, and the effect of lamination is not obtained. The lower limit of the layer thickness is about 50 °.

The Fe layer 3 shows negative magnetostriction after the heat treatment. Therefore, it is preferable that the average magnetostriction of the entire film is reduced by adjusting the soft magnetic alloy layer 4 to have a positive magnetostriction by adjusting the M / C concentration ratio or the T concentration. The magnetostriction can also be adjusted by changing the heat treatment temperature or the layer thickness ratio between the Fe layer 3 and the soft magnetic alloy film 4, and can be set according to various uses.

FIG. 4 shows one embodiment of the invention described in claim 4, wherein the laminated film 21 of this embodiment is made of pure iron.
Between the layer 23 and the soft magnetic alloy layer 24 equivalent to the previous embodiment,
In this configuration, a diffusion layer 25 having an intermediate concentration between the layer 23 and the soft magnetic alloy layer 24 is interposed. In the diffusion layer 25, the concentrations of the additional elements such as the elements T, M and C gradually decrease toward the Fe layer 23, and the additional elements such as the elements M, T and C decrease toward the soft magnetic alloy layer 24. The concentration gradient is set so that the concentration gradually increases. Accordingly, in the laminated film 21 of this embodiment, the concentration distribution in the thickness direction is as shown in FIG.

In order to obtain the laminated film 21 having the above structure, the laminated film 1 having the structure shown in FIG. 1 can be obtained by heat-treating the laminated film 1 for a required time to cause element diffusion between the Fe layer 3 and the soft magnetic alloy layer. .

The same effect as that of the embodiment described above can be obtained in the laminated film having this configuration.

Example (1) Film formation Using the RF bipolar sputtering apparatus shown in FIG. 3, both the cathode provided with a pure iron target and the cathode provided with an iron target provided with graphite pellets and Hf pellets were simultaneously discharged. At the same time, by rotating the substrate holder, the substrate was moved back and forth between the two cathodes to form a multilayer film in which Fe layers and FeHfC layers were alternately laminated. In this multilayer film, the film thickness per Fe layer, the film thickness per FeHfC layer, and the number of layers thereof are as shown in Table 1, and the total film thickness is 5 to 6 μm.
m. The composition of the FeHfC film in this laminated film is Fe
_83.5 Hf _5.9 C _10.6 .

(2) Heat treatment and measurement After film formation, measurement of the magnetic properties of the film as it is,
The magnetic properties after the magnetic field-free heat treatment were measured. Table 1 shows the results.

In the laminated film of the samples a, b and c shown in Table 1, the Fe layer and the F layer
For each of the eHfC layers, the thickness per layer is 59 mm, 115
Å, 210Å, but both exhibited high saturation magnetic flux density of 20,000 G or more and good soft magnetic properties after heat treatment. In particular, sample c with a total thickness of 275 layers with a thickness of 210mm per layer
The laminated film showed a high magnetic permeability of 3140 after heat treatment at 550 ° C. (holding for 20 minutes), and exhibited excellent thermal stability of 2520 even when the heat treatment temperature was raised to 650 ° C. However, the magnetostriction constant of the laminated film of this sample c is -1.9 × 10 ^{-6, which} is slightly large. This can be reduced by increasing the thickness of the FeHfC layer with respect to the Fe layer. As shown in the sample d in Table 1, ^10-7 λs can be obtained. Also, the magnetostriction constant λ
The s can be adjusted by changing the composition of the FeHfC layer (to make the λs of the FeHfC layer more positive).
As shown in the table, increasing the C concentration or the element T
By adding (Co or Ni), it is possible to similarly set λs of the order of 10 ⁻⁷ .

[Effects of the Invention] As described in detail above, the soft magnetic alloy layer used in the laminated film according to the present invention is composed of fine crystal grains containing Fe as a main component. In contrast, a film exhibiting high saturation magnetic flux density and high magnetic permeability can be obtained even when heat treatment is performed in the absence of a magnetic field, and the process can be simplified as compared with the case where heat treatment is performed by applying a magnetic field. Also,
The soft magnetic alloy layer contains an element M (Ti, Zr, V, Hf, Nb, Ta, Mo,
W) and C are added as components for improving soft magnetism, and the metal structure is composed of fine crystal grains. Is obtained.

Further, since the soft magnetic alloy layer is composed of fine crystal grains and the added element M forms carbide with C,
Even when heated in the glass welding step, the crystal grains do not become coarse and the above characteristics are maintained.

Furthermore, by adding the element T (Co, Ni) in addition to the above composition and adjusting the magnetostriction, it is possible to prevent the deterioration of the soft magnetic properties due to various strains generated in the magnetic head manufacturing process and the like. .

That is, since the soft magnetic laminated film of the present invention is obtained by laminating a soft magnetic alloy layer having excellent soft magnetic properties as described above and an Fe layer having excellent saturation magnetic flux density,
An excellent saturation magnetic flux density of 20,000 G or more can be obtained while maintaining excellent soft magnetic properties and heat resistance of the (T) -MC based soft magnetic alloy film alone.

Therefore, the soft magnetic laminated film of the present invention is suitable as a material for a magnetic head for high density recording requiring a saturation magnetic flux density of 20,000 G or more.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a laminated film according to an embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing a concentration distribution in the thickness direction of the laminated film shown in FIG. 1; FIG. 3 is a configuration diagram showing an example of a sputtering apparatus suitable for producing the laminated film shown in FIG. FIG. 4 is a sectional view showing a laminated film according to another embodiment of the present invention, and FIG. 5 is a diagram showing a concentration distribution of the laminated film shown in FIG. DESCRIPTION OF SYMBOLS 1 ... Laminated film, 2 ... Substrate, 3 ... Fe layer, 4 ... Soft magnetic alloy layer, 5 ... Substrate holder, 7,8 ... Cathode, 10 ...
Substrate, 11 Target, 12, 13 Pellets, 14
target.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G11B 5/31 G11B 5/31 C

Claims (4)

(57) [Claims] A soft magnetic alloy layer represented by a composition formula of FexMzCw and an Fe layer are alternately laminated, and the soft magnetic alloy layer is entirely formed of fine crystal grains having an average grain size of 0.08 μm or less, A soft magnetic laminated film characterized in that a part of fine crystal grains contains a crystal phase of a carbide of the element M. However, in the above composition formula, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
W is a metal element of at least one of W or a mixture thereof, and the composition ratio x, z, w satisfies the relationship of 50 ≦ x ≦ 96 2 ≦ z ≦ 30 0.5 ≦ w ≦ 25 x + z + w = 100 in atomic%. It shall be. 2. A soft magnetic alloy film represented by a composition formula of FexTyMzCw and an Fe layer are alternately laminated, and the soft magnetic alloy layer is entirely composed of fine crystal grains having an average grain size of 0.08 μm or less, A soft magnetic laminated film characterized in that a part of fine crystal grains contains a crystal phase of a carbide of the element M. However, in the above composition formula, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
Among W, at least one metal element or a mixture thereof, and T represents at least one of Co and Ni, and the composition ratio x, y, z, w is 50 ≦ x ≦ 96 0.1 ≦ y in atomic%. ≤20 2≤z≤30 0.5≤w≤25 x + z + w = 100 3. The soft magnetic alloy layer according to claim 1, wherein the soft magnetic alloy layer has a structure in which fine crystal grains having an average crystal grain size of 0.08 μm or less and an amorphous phase are mixed, and a part of the fine crystal grains is formed. A soft magnetic layered film containing a crystal phase of a carbide of element M. 4. A soft magnetic laminate characterized in that an interface between the Fe layer and the soft magnetic alloy layer according to claim 1, 2 or 3, is provided with a concentration gradient of constituent elements of the soft magnetic alloy layer. film.