JPH10223435A - Magnetic thin film and magnetic device employing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic thin film excellent in reliability and magnetic characteristics by including a magnetic film a mother phase of magnetic crystal grain having mean volume and mean surface area satisfying a specified expression. SOLUTION: A film is deposited on a nonmagnetic ceramic substrate by RF magnetron sputtering under a predetermined sputtering condition of discharge gas pressure, substrate temperature, additive element, reaction gas flow rate, etc. The crystal film structure has such a cross-section as the magnetic crystal grain, which can be regarded to be substantially acicular or columnar, is grown substantially normal to the surface of the substrate. The crystal structure has means sizes dL and dS in the long and short sides directions of grain satisfying the relations 5μm<dS<60μm, dL>100μm. The mean volume Va and the mean surface Sa of magnetic crystal grain sufficiently satisfy the expression; Sa>4.84Va<2/3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic thin film and a magnetic device using the same, and more particularly, to a magnetic sensor including a magnetic recording head, a magnetic reproducing head, and a magnetic impedance sensor. Magnetic thin film useful as a magnetic circuit component such as a magnetic coil, an inductor, or a magnetic induction heating member such as an IH rice cooker and an IH hot plate, and a magnetic head, a magnetic sensor, and a magnetic circuit using the soft magnetic thin film The present invention relates to a magnetic device such as a component or a magnetic induction heating member.

[0002]

2. Description of the Related Art The write performance of a magnetic recording head is improved with the increase in magnetic recording density, the magnetic impedance change rate of a magnetic impedance sensor is improved, and the electromagnetic-heat conversion efficiency of a magnetic induction heating material is improved. There is a demand for a magnetic material that achieves both excellent magnetic properties and high saturation magnetic density over a wide range of magnetic devices using soft magnetic materials, such as improvements. In recent years, as a material that satisfies these conditions, an Fe—N-based or Fe—N alloy in which granular magnetic microcrystals of about 5 to 20 nm are precipitated from an amorphous film containing a magnetic element by performing a heat treatment.
C-based materials have been developed (for example, Hasegawa: Journal of the Japan Society of Applied Magnetics, 14, 319-322 (1990),
NAGO IEEE, Trans, magn., VOl.28, NO.5 (1992)). In these materials, as in the case of the Co-based amorphous material, the size of the magnetic crystal grains is made sufficiently smaller than the exchange coupling distance so that each microcrystal grain is three-dimensionally exchangeable with other adjacent microcrystal grains. It is considered that soft magnetic characteristics are realized by performing the action, thereby canceling each crystal magnetic anisotropy and reducing the apparent crystal magnetic anisotropy.

[0003]

Among these microcrystalline materials, those in which the precipitated or grain-grown microcrystalline particles have a substantially magnetic metal composition (for example, Fe or FeCo), have a high saturation magnetic flux of 1.2 T or more. Corrosion resistance has become an issue for materials having a high density. Therefore, for example, an attempt has been made to improve corrosion resistance by dissolving an element that forms a passivation such as Al in α-Fe. However, corrosion-resistant elements such as Al that form a passivation are basically oxides, Since the free energy of nitride formation is low, it reacts preferentially with light elements such as oxygen, nitrogen, carbon, and boron used for amorphization or microcrystallization, and the corrosion-resistant element becomes α-Fe. It hardly remains in a state of solid solution in microcrystals. Furthermore α
-When an amount sufficient to impart corrosion resistance to Fe is added,
There is a problem that the saturation magnetic flux density is greatly reduced.

On the other hand, when these magnetic materials are used in, for example, a magnetic head, they are subjected to a heat treatment in a process of fusing with glass necessary for producing the magnetic head. At this time, the matching of the melting point of the glass, the coefficient of thermal expansion between the substrate and the glass and the magnetic film, and the optimum microcrystal deposition temperature of the magnetic material influence the characteristics of the magnetic head. The heat treatment temperature for heading is desirably 500 ° C. or higher from the viewpoint of glass reliability, and the optimum heat treatment temperature for the magnetic material needs to be higher than that.

When the magnetic head is, for example, a metal-in-gap head (MIG head) in which a magnetic thin film is formed on ferrite, if the heat treatment temperature is too high, an interface reaction between the ferrite and the magnetic film proceeds, and the magnetic film / ferrite interface is formed. The resulting magnetically degraded layer becomes thicker and the pseudo gap noise increases. When the magnetic head is a LAM head in which a magnetic thin film and an insulating film are laminated on a non-magnetic substrate, the magnetic film and the respective substrates have different coefficients of thermal expansion. Thermal stress increases,
The soft magnetic characteristics of the film deteriorate due to an increase in anisotropic energy due to the inverse magnetostriction effect. For this reason, it is desirable that the optimal heat treatment temperature range of the magnetic material is about 550 ° C. or less.

However, as described above, a microcrystalline material in which a corrosion-resistant element is sufficiently dissolved in metal microcrystals is required to have a stable crystal structure and a sufficiently small magnetostriction constant.
There was a problem that heat treatment had to be performed at a temperature of about 00 to 700 ° C. or higher.

Further, since many of these microcrystalline magnetic thin films essentially have many interfaces between magnetic particles per unit volume, magnetic crystal grains whose interface energy is a driving force during heat treatment are used. There is a problem in that the optimum heat treatment temperature range where remarkable grain growth is exhibited and good soft magnetism is narrowed, the characteristics are varied, and the use temperature range is largely limited.

On the other hand, a problem common to many thin film materials is peeling of a film from a substrate due to internal stress of the film or fine cracking of the substrate. For example, in general, the internal stress of a film formed on a substrate by a sputtering method or the like has a compressive stress or a tensile stress. When the adhesion strength between the substrate and the film is low or when the breaking strength of the substrate material is low, problems such as film peeling occur depending on the shape and surface state of the substrate.

The present invention has been made in view of the above-mentioned problems, such as thermal stability and corrosion resistance, associated with increasing the saturation magnetic flux density of a soft magnetic thin film material.
The above problems were solved by studying various conditions in the crystal grain size structure and size, and further studying the element composition and the conditions and composition of the underlayer to achieve the optimum structure. An object of the present invention is to provide an excellent magnetic thin film and a magnetic device using the thin film.
In addition, the present invention solves the conventional problems by studying the underlying structure between the substrate and the magnetic film in consideration of the problem of delamination from the substrate due to the internal stress of the film and the destruction of the substrate. Another object is to provide an excellent magnetic thin film and magnetic device.

[0010]

In order to achieve the above object, the magnetic thin film of the present invention has an average volume Va and an average surface area S
a) includes a magnetic film having a magnetic crystal grain satisfying the following relational expression as a mother phase.

Sa> 4.84 Va ^2/3 (1) With such a configuration, it is possible to realize excellent soft magnetic characteristics while having a high saturation magnetic flux density (for example, 1.2 T or more). One magnetic crystal grain is crystallographically almost a single crystal. It is considered that the anisotropy in the crystal is mainly governed by the magnetocrystalline anisotropy, and a plurality of adjacent magnetic crystal grains existing in the magnetic film are exchange-coupled to each other. At this time, the exchange force exerted by the magnetic crystal grains on each other is such that the magnetic crystal grains have a sufficiently large surface area as shown in the above formula (1) if the number of magnetic crystal grains existing per unit volume is the same. This enhances the soft magnetic properties.

In the above-mentioned magnetic thin film, the number of magnetic crystal grains is 5.
It is preferred to have an average maximum length greater than 0 nm.

According to this preferred example, it is possible to realize excellent soft magnetic characteristics and heat treatment stability in a wide temperature range of the soft magnetic characteristics while having a high saturation magnetic flux density (for example, 1.2 T or more). Generally, a soft magnetic material having a high saturation magnetic flux density is realized when the average crystal grain size of substantially spherical magnetic crystal grains (Sa <4.84 Va ^2/3 ) is about 20 nm or less. Even if the average maximum length of the crystal grains is greater than about 50 nm, soft magnetic characteristics can be realized if the surface area of the magnetic crystal grains is sufficiently large as in the above formula (1). Also, if the average maximum length of the magnetic crystal grains is sufficiently long as shown in the above range, the average crystal volume is substantially larger than a magnetic material of fine crystal grains that can be regarded as a sphere. Therefore, the total surface area or the area occupied by all the interfaces of the magnetic crystal grains per unit volume in the magnetic film can be reduced, and as a result, the driving force of the grain growth during the heat treatment of the whole magnetic material is small. Therefore, the stability of the heat treatment is improved.

Further, in the magnetic thin film, the magnetic crystal grains are formed of a substantially needle-like body, a substantially columnar body, or a multi-branched body composed of a combination thereof, and the average crystal size of the magnetic crystal grains in the lateral direction is reduced. Preferably, it is larger than 5 nm and smaller than 60 nm.

According to this preferred example, excellent soft magnetic characteristics and heat treatment stability in a wide temperature range of soft magnetic characteristics are realized while having a high saturation magnetic flux density (for example, 1.2 T or more), and the corrosion resistance is further improved. I do.

The thermal stability in a wide temperature range is such that the magnetic crystal grains of the magnetic thin film are formed in a substantially columnar body, a substantially needle-like body, or a substantially needle-like portion and a substantially columnar portion constituting a multi-branched crystal in the longitudinal direction. This is because the average maximum length (average crystal size) is 50 nm or more, which is larger than that of the conventional microcrystalline material, and thus the grain growth is difficult due to a small interfacial energy per unit volume. Also, it is generally recognized that having a columnar or needle-like crystal structure causes deterioration of magnetic properties due to shape anisotropy, but in the present invention, the crystal surface is large due to a large surface area per crystal grain volume. By performing strong exchange interaction between particles, shape magnetic anisotropy is suppressed and soft magnetic properties are improved. Further improvement in corrosion resistance is that if the size and shape of the magnetic crystal particles are in the above-mentioned range, the potential difference between each crystal particle based on the variation of the electrochemical potential between the crystal particles is averaged, and the corrosion due to the local battery effect is reduced. This is because progress is suppressed. In the case of a magnetic thin film having an average crystal size in the transverse direction of 60 nm or more, it is difficult to achieve a high saturation magnetic flux density of 1.2 T or more, and at the same time to achieve both soft magnetic characteristics and corrosion resistance. Good heat treatment stability cannot be obtained.

Another structure of the magnetic thin film according to the present invention is that a substantially crystalline needle-like or substantially columnar magnetic crystal grain is used as a mother phase, and the average crystal size dS in the short direction and the average crystal size in the long direction of the magnetic crystal grain are used. The size dL includes a magnetic film satisfying the following relational expression.

5 nm <dS <60 nm (2) dL> 100 nm (3) Still another configuration of the magnetic thin film of the present invention is a magnetic crystal grain including a polybranched crystal composed of a combination of a substantially needle-like body or a substantially columnar body. And a magnetic film, wherein the average crystal size ds in the short direction of the substantially needle-like body or the substantially columnar body and the average maximum length dl of the multi-branched crystal each satisfy the following relational expression. I do.

5 nm <ds <60 nm (4) dl> 50 nm (5) With such a configuration, excellent soft magnetic characteristics and soft magnetic characteristics can be obtained while having a high saturation magnetic flux density (for example, 1.2 T or more). Stability of heat treatment in a wide temperature range is realized, and corrosion resistance is further improved. The thermal stability over a wide temperature range is such that the magnetic crystal grains of the magnetic thin film have a substantially columnar, substantially acicular or multi-branched shape, and the average particle size is larger than that of the conventional microcrystalline material. This is because grain growth is difficult due to low interfacial energy. In addition, the crystal grains perform strong exchange interaction to suppress shape magnetic anisotropy, and cancel out each other's transverse crystal magnetic anisotropy to produce soft magnetic characteristics. Further, the improvement of the corrosion resistance can be achieved if the size and shape of the magnetic crystal particles are in the range of the above formulas (2) and (3) (or in the range of the above formulas (4) and (3)). This is because the potential difference between the crystal grains based on the variation of the electrochemical potential is averaged, and the progress of corrosion due to the local battery effect is suppressed. Note that dS (or ds) is 60n
m or more, it is difficult to achieve a high saturation magnetic flux density of 1.2 T or more, and at the same time to achieve both soft magnetic characteristics and corrosion resistance.
When s) is 5 nm or less, heat treatment stability in a wide temperature range is deteriorated. Similarly, when dL is 100 nm or less (or dl is 50 nm or less), thermal stability deteriorates.

Further, in the magnetic thin film, it is preferable that crystal orientations of magnetic crystal grains adjacent to each other are different at least in an in-plane direction. According to this preferred example, the cancellation ratio of the magnetic anisotropy is improved, and the soft magnetic characteristics can be improved by making the apparent needle magnetic, columnar or multi-branched crystalline magnetic anisotropy smaller. .

In the magnetic thin film, C, B,
At least one light element selected from O and N;
It is preferable to include an element having a lower free energy of oxide and / or nitride formation than e.

For example, when a magnetic film is formed by a sputtering method, C, B, O, and N elements are mainly dissolved in a metal magnetic element, and an element having a lower free energy of oxide and nitride formation than Fe is used. By controlling the bonding of the island-like crystal structure generated during the initial growth process on the substrate and the bonding of the grains during the film formation, the crystal grains are preferably formed into needle-like, column-like, or multi-branched forms. A film structure having a large surface area per volume can be realized. In particular, by combining a plurality of the above-mentioned additional elements, a reaction product of various free energy of formation and an intermediate reactant are generated, so that the film structure can be realized with a small amount of the additive as a whole, and as a result, High saturation magnetic flux density is maintained.

In the magnetic thin film, it is preferable that the magnetic crystal grains contain an element having a lower free energy of oxide and / or nitride formation than Fe.

In a conventional microcrystalline material precipitated from an amorphous phase, most of the elements precipitate at the grain boundaries during the heat treatment process. According to this preferred example, however, the elements are contained in the magnetic metal crystal grains. Since the film is formed in a state of solid solution, the amount of solid solution sufficient to form an oxide protective film on the surface of the magnetic crystal grains can be maintained even with a small amount of addition. Further, the element controls the initial grain shape on the substrate, and consequently has a function of forming a magnetic film having a preferred grain shape and size according to the present invention.

In the magnetic thin film, the element having a lower free energy of oxide and / or nitride formation than Fe is a group IVa element, a group Va element, Al, Ga, S
It is preferably at least one element selected from i, Ge and Cr.

These elements can realize the preferable film structure of the present invention with a small amount of addition, and at the same time, can achieve both high corrosion resistance and excellent magnetic properties. This is considered to be related to the relatively high diffusion rate of these elements in the magnetic metal crystal.

In the magnetic thin film, a microcrystalline or amorphous grain boundary compound made of at least one selected from carbides, borides, oxides, nitrides and metals is present at the grain boundaries of the magnetic crystal grains. Preferably, it is included.

According to this preferred example, the grain shape of the magnetic crystal grains is controlled by the grain boundary compound, so that the preferred crystal grain structure of the present invention can be realized, and the stability of heat treatment of magnetic properties is improved.

Further, assuming that the average shortest length of the grain boundary compound is T, it is preferable that the average shortest length T of at least 30% of the grain boundary compound satisfies the following relational expression. 0.1 nm ≦ T ≦ 3 nm (6) If the average shortest length T of the grain boundary compound is smaller than 0.1 nm, a sufficient effect of suppressing grain growth cannot be expected, and if it is larger than 3 nm, exchange coupling between magnetic crystal grains. And the saturation magnetic flux density may be reduced. In particular, the average shortest length T of at least 30% of the grain boundary compound is 0.1 nm ≦ T ≦ 3
It was confirmed that the soft magnetic property and the stability of the heat treatment can be compatible at the time of nm.

Further, the magnetic thin film includes a base film composed of at least one layer and a magnetic film formed on the base film, wherein at least one layer forming the base film is made of an oxide rather than Fe. And / or preferably contains an element having a low free energy of nitride formation.

According to this preferred example, the diffusion reaction between the magnetic film and the underlayer is suppressed, and the above-mentioned thermal stability in the vicinity of the initially formed film having the preferred crystal grain structure can be realized. For example, when the element is in a solid solution state, it reacts with an active element such as oxygen, nitrogen, or carbon diffused from a magnetic film or a base film, and the formed reaction product layer serves as a diffusion prevention barrier. Further, when the element is present as a stable compound, even if the compound does not form a complete layer, the active element that diffuses,
The diffusion path can be narrowed by the compound, and a reaction product is formed near the diffusion path, thereby suppressing the diffusion reaction.

[0032] The magnetic thin film includes at least one underlying film and a magnetic film formed on the underlying film, and at least one of the layers constituting the underlying film that is in contact with the magnetic film. However, it is preferable that the material has a lower surface free energy than Fe.

For example, when the magnetic film of the present invention is formed by a sputtering method, in particular, the grain growth of initially formed grains of the magnetic film is suppressed, and the above-described preferable crystal grain structure can be realized from the vicinity of the substrate. Conversely, if the surface free energy is larger than Fe, the crystal near the interface becomes too thick, and a magnetically degraded layer is formed near the substrate.
In the case of an IG head, such a magnetically degraded layer causes a pseudo gap or a deterioration in head reproduction sensitivity. Further, when the magnetic film is divided by the insulating layer at a relatively small interval of several tens nm to several μm as in a LAM head, for example, the influence of the crystallinity of the excessively grown initial formed grains remains on the entire film. . Further, since the free energy stored at the interface of the underlayer can be controlled, the internal stress between the film, the underlayer, and the substrate can be reduced, and the magnetic deterioration due to the inverse magnetostriction effect can be suppressed. A desirable thickness of the layer formed of a substance having a surface free energy equal to or less than that of the magnetic film in the underlayer is 0.
1 nm or more.

Further, the magnetic thin film includes at least one underlying film and a magnetic film formed on the underlying film, and at least one of the layers constituting the underlying film which is in contact with the magnetic film. Are Al, Ba, Ca, Mg,
It is preferably any compound selected from carbides, oxides, nitrides, and borides of at least one element selected from Si, Ti, V, Zn, Ga, and Zr.

According to this preferred example, the reaction between the magnetic film and the base film is suppressed, and the grain shape of the initially formed grains of the magnetic film can be controlled, so that a preferable crystal grain structure of the magnetic film from the vicinity of the initially formed film can be realized. The internal stress can be controlled.

The magnetic thin film includes at least one underlying film and a magnetic film formed on the underlying film, and at least one of the layers constituting the underlying film that is in contact with the magnetic film. Is C, Al, Si, Ag, C
It is preferable to be made of at least one substance selected from u, Cr, Mg, Au, Ga and Zn.

According to this preferred example, since the grain shape of the initially formed grains of the magnetic film can be controlled, a preferable crystal grain structure of the magnetic film of the present invention can be realized from the vicinity of the initially formed film.

The magnetic thin film includes an underlayer consisting of at least one layer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film, A underlayer B in contact with A, wherein said underlayer B is Al, Ba, Ca, Mg, Si, Ti, V, Z
n, Ga, and Zr, and the underlayer A may be made of a compound selected from carbides, oxides, nitrides, and borides of the material constituting the underlayer B. preferable.

According to this preferred embodiment, the reaction between the magnetic film and the underlayer or the substrate is suppressed, and the grain shape of the initially formed grains of the magnetic film can be controlled. Realization of a crystal grain structure and control of internal stress become possible.

Further, the magnetic thin film includes an underlayer consisting of at least one layer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and the underlayer A and the underlayer. A, wherein the underlayer A includes Al, Ba, Ca, Mg, Si, Ti, V, Z
n, Ga and Zr, and the underlayer B may be made of a compound selected from carbides, oxides, nitrides and borides of the material constituting the underlayer A. preferable.

According to this preferred embodiment, the reaction between the magnetic film and the underlayer or the substrate is suppressed, and the grain shape of the initially formed grains of the magnetic film can be controlled. A crystal grain structure can be realized.

Further, the magnetic thin film includes an underlayer consisting of at least one layer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film, A underlayer B in contact with A, said underlayer A containing at least one element selected from the main constituent elements contained in said magnetic film and at least one element selected from oxygen and nitrogen, and It is preferable that the underlayer B contains oxygen or nitrogen more than the film and is made of any compound selected from carbide, oxide, nitride, and boride.

According to this preferred embodiment, the reaction between the magnetic film and the underlayer or the substrate is suppressed, and the grain shape of the initially formed grains of the magnetic film can be controlled. Can be realized.

Here, the main constituent element refers to an element constituting the magnetic film and contained in an amount that can be analyzed, specifically, at least 0.5 atomic% in the magnetic film. Means the element.

The magnetic thin film includes at least one underlying film and a magnetic film as a main magnetic layer formed on the underlying film, wherein the underlying film is in contact with the magnetic film. A and an underlayer B in contact with the underlayer A, wherein the underlayer A is formed by alternately laminating at least one sub-magnetic layer and a split layer, and the underlayer B is formed of an oxide, a nitride, or a carbide. And a compound selected from borides.

According to this preferred example, the growth of the initially formed grains is suppressed because the initially formed film is miniaturized by the dividing layer, and the magnetic film formed thereover realizes the preferable crystal grain structure of the present invention. It's easy to do. Further, the underlayer B suppresses a reaction between the magnetic film and the substrate or the underlayer. Here, the dividing layer may be a layer made of a metal, an alloy, a carbide, an oxide, a nitride, a boride, or the like having a different composition from the magnetic film or the sub-magnetic layer.

In this case, it is preferable that the dividing layer shares at least one element with the magnetic film and contains more oxygen or nitrogen than the magnetic film. According to this preferred example, since the same component is shared, interface diffusion is suppressed, and the heat resistance of the magnetic properties is improved.

It is preferable that the thickness of the sub-magnetic layer and the thickness of the split layer (the thickness t _M of the sub-magnetic layer and the thickness t _S of the split layer) satisfy the following relational expression. 0.5 nm ≦ t _M ≦ 100 nm (7) 0.05 nm ≦ t _S ≦ 10 nm (8) According to this preferred example, since the initial grain growth can be effectively suppressed, the magnetic film formed on the It is easy to realize the preferred crystal grain structure.

It is preferable that the total thickness of the sub magnetic layer and the split layer is 300 nm or less. If the thickness of t _M is smaller than 0.5 nm or larger than 100 nm, the magnetic properties of the laminated base are deteriorated. When the thickness of t _M is 30 nm or less, the internal stress in the vicinity of the initially formed film is reduced, and stress relaxation between the substrate and the magnetic thin film can be realized.
On the other hand, if the split layer thickness is smaller than 0.05 nm, the effect is difficult to obtain, and if it is larger than 10 nm, the magnetic coupling with the main magnetic film on the laminated base is weakened, which is not preferable.

The magnetic thin film includes at least one underlying film and a magnetic film formed on the underlying film, and at least a layer of the underlying film that is in contact with the substrate is made of an amorphous magnetic material. Alternatively, it is preferable that the fine magnetic layer has a magnetic crystal grain whose average particle diameter d satisfies the following relationship as a mother phase.

D ≦ 20 nm (9) Generally, a thin film material formed by a sputtering method or the like has an internal stress immediately after the film formation, and the value of the internal stress, the adhesive strength between the substrate and the film, the thickness of the film, Depending on the breaking strength of the substrate, the film is peeled off and the substrate is broken. The biggest cause is the internal stress of the film, but the film formation conditions of the functional film having high performance are not always the case where the internal stress immediately after the film formation is the lowest. The inventor, despite having internal stress, made various examinations to examine conditions with little film peeling and substrate destruction.As a result, the following mechanism was assumed, and the above mechanism was verified by assuming the following mechanism. Reached.

That is, the surface roughness of the substrate used for film formation is about several nm to several hundred nm (for example, 3 nm to 80 nm).
0 nm), but in fact, the substrate surface has
Polishing marks and the like having a sharp tip of the Dar remain. Generally, when a film is formed on a substrate by using a sputtering method, an island-like structure is generated on the substrate in an initial formation process, and such a groove tends to remain in a gap between the island-like crystals. One cause of film peeling is the presence of a gap at the interface between the substrate surface and the film due to such a groove portion. When the film has internal stress, the internal stress concentrates on the remaining groove, and the substrate is easily cracked from the groove having a sharp tip. Therefore, one solution is to eliminate the grooves on the substrate surface. Another solution is to fill a sharp tip groove.

As described above, peeling of the film and cracking of the substrate can be suppressed by using the amorphous magnetic material as a matrix or forming a fine underlayer in which the average crystal grain is reduced to 20 nm or less as the underlayer of the thin film. it can. The average particle size is 2
If it is larger than 0 nm, this effect is gradually lost.

As described above, a common problem of the thin film material is as follows.
Although film peeling and substrate destruction occur, in the case of magnetic materials, after film formation, the film is heat-treated at a temperature several hundred degrees higher than the film-forming temperature, and the internal stress including the thermal stress of the substrate and the film is reduced to zero after the heat treatment. Need to be near. Since the stress relaxation occurs inside the film due to the heat treatment, a significant difference occurs between the film internal stress immediately after the film formation and after the heat treatment. Therefore, in the case of a magnetic thin film, especially among magnetic thin films, even if the film thickness is only a few μm, film peeling and substrate cracking are likely to occur, and the significance and effect of providing a miniaturized layer within the scope of the present invention is great.

In particular, in a MIG head or the like, if the miniaturized layer provided between the ferrite and the magnetic film is non-magnetic, a pseudo gap may be caused. Therefore, a micro magnetic layer made of a magnetic material is preferable.

[0056] In the magnetic thin film, the thickness t _r of the fine magnetic layer, it is preferable that the thickness t _f of the magnetic film satisfies the following relationships. _{10nm <t r <t f /} 3 (10) The thickness of the fine magnetic layer becomes difficult to obtain the effect of substrate crack suppressed in the 10nm or less. It is considered that this is because the unevenness on the substrate surface cannot be sufficiently filled. If the thickness of the fine magnetic layer is not more than about 1/3 of the thickness of the magnetic film, it is difficult to make full use of the characteristics of the main magnetic film. The maximum thickness of the fine magnetic layer t _r is preferably about 300 nm, is likely to achieve both the suppression and magnetic properties cracking With such a thickness.

In the magnetic thin film, it is preferable that the fine magnetic layer and the magnetic film have at least one common element.

According to this preferred example, since the fine magnetic layer and the magnetic film have a common element, the electrochemical potentials of the layers are close to each other, so that corrosion due to the local battery effect between different layers is suppressed, When the magnetic layer and the magnetic film are formed continuously, peeling between different layers is suppressed by appropriate mutual diffusion of each layer.

The common element preferably contains an element having the lowest free energy of oxide and / or nitride formation among elements contained in the fine magnetic layer or the magnetic film.

According to this preferred example, the progress of corrosion between the fine magnetic layer and the magnetic layer is further suppressed. Further, according to a further preferred example in which the fine magnetic layer and the magnetic film are formed continuously, formation of a magnetically degraded layer due to excessive mutual diffusion of each layer can be suppressed.

[0061] The common element is preferably at least one element selected from oxygen, nitrogen, carbon and boron. The addition of these elements makes it possible to easily realize the preferable crystal grains of the magnetic film and the structure of the fine magnetic layer.

The fine magnetic layer is made of a group IIIa, IVa
It preferably contains at least one element selected from the group consisting of group III and group Va. Group IIIa, IVa, and Va elements have lower free energy of oxide and nitride formation than Fe and have excellent corrosion resistance. Further, by controlling the amount of addition, Co and Fe are easily made finer, and the fine magnetic layer is easily formed.

The magnetic thin film includes an underlayer consisting of at least one layer, and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and the underlayer A and the underlayer. A, including an underlayer B in contact with A, an element group concentration C ₁ (atomic weight%) of oxygen, nitrogen, carbon, and boron in the magnetic film, and an element group of oxygen, nitrogen, carbon, and boron in the underlayer A It is preferable that the concentration C ₂ (atomic weight%) and the concentration C ₃ (atomic weight%) of the element group composed of oxygen, nitrogen, carbon and boron in the underlayer B satisfy the following relational expression.

0 ≦ C ₁ ≦ C ₃ <C ₂ (11) According to this preferred example, at least one of the underlayer A and the underlayer B functions as a fine magnetic layer. Have that role. Underlayer A in contact with magnetic film
Is at least one selected from oxygen, nitrogen, carbon, and boron
In order to have a finer structure with a high content of two elements,
It not only serves as a fine magnetic layer but also has the effect of suppressing the growth of grains formed initially in the magnetic film, and improves the magnetic properties of the entire magnetic thin film.

The magnetic thin film includes an underlayer consisting of at least one layer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film, A, including an underlayer B in contact with A, an element group concentration C ₁ (atomic weight%) of oxygen, nitrogen, carbon, and boron in the magnetic film, and an element group of oxygen, nitrogen, carbon, and boron in the underlayer A It is preferable that the concentration C ₂ (atomic weight%) and the concentration C ₃ (atomic weight%) of the element group composed of oxygen, nitrogen, carbon and boron in the underlayer B satisfy the following relational expression.

0 ≦ C ₁ ≦ C ₂ ≦ C ₃ (12) According to this preferred example, at least one of the underlayer A and the underlayer B functions as a fine magnetic layer. Have that role. Underlayer A in contact with magnetic film
Can be suppressed by increasing the content of at least one element selected from oxygen, nitrogen, carbon, and boron in the magnetic film as compared with the magnetic film. Improve the magnetic properties of

In the above equation (12), the element group concentration C ₁
When C ₃ and C ₃ are different, it is preferable that the element group concentration C ₂ changes almost continuously in the film thickness direction so as to reduce the difference in concentration at the layer interface.

According to this preferred example, in the underlayer A,
At least one selected from oxygen, nitrogen, carbon and boron
By continuously modulating the contents of the two elements, formation of a magnetically degraded layer due to excessive mutual diffusion of the layers can be suppressed. Further, since the shape and size of the crystal grains are continuously changed, the magnetic continuity from the underlayer B to the magnetic film is improved, and the soft magnetic characteristics are improved.

The magnetic thin film including the fine magnetic layer is preferably formed on a substrate having irregularities.

For example, as one of the manufacturing processes of the MIG head, several to several hundred μm (for example, 5 μm
５００500 μm), and several μm
In some cases, a film is formed on a substrate having an uneven shape of several mm (for example, 1 μm to 3 mm). In this case, since the film adhesion area per unit volume of the substrate increases, the total film stress applied near the substrate surface increases, and the probability of film peeling and substrate cracking increases inevitably. Therefore,
When the substrate has irregularities, the formation of the miniaturized underlayer can prevent film peeling and substrate cracking.

It is preferable that the magnetic thin film has a base film or a magnetic film formed on a high-resistance substrate or a high-resistance material.

When the resistance value of the substrate or the material is about several tens μΩcm or less, a local battery is formed between the magnetic film, the underlayer, and the magnetic thin film, and corrosion is likely to occur. The resistance value of a preferable substrate or material for forming the underlayer or the magnetic film of the present invention is several hundred μΩcm or more (for example, 200 μΩc
m or more).

Further, the magnetic thin film is a magnetic thin film formed on a substrate having a barrier layer formed thereon, wherein the barrier layer is made of an oxide of at least one element selected from Al, Si, Cr and Zr. Alternatively, it is preferable to have a thickness du made of nitride and satisfying the following relational expression.

0.5 nm <du <10 nm (13) Al, Si, Cr and Zr, which are high-resistance materials, are formed on the substrate.
By forming at least one or more oxides or nitrides selected from the group consisting of:
Corrosion due to the local battery effect between the base film and the magnetic film is suppressed, and a diffusion reaction between the substrate and the base film or the magnetic film during heat treatment can be suppressed. The above effect can be obtained if the thickness of the barrier film is more than 0.5 nm. However, if the thickness is more than 10 nm, it is not preferable because, for example, when a MIG head is formed, a pseudo gap is caused.

Another configuration of the magnetic thin film of the present invention is as follows.
(M _a X ¹ _b Z ¹ _c ) Including a magnetic film having a composition represented by _{100-d Ad} .

Here, M is at least one magnetic metal element selected from Fe, Co and Ni, and X ¹ is S
i is at least one element selected from Al, Ga and Ge, Z ¹ is at least one element selected from the group IVa, Va and Cr, and A is at least one element of O and N And a, b, c and d are numerical values satisfying the following relational expression.

0.1 ≦ b ≦ 26 0.1 ≦ c ≦ 5 a + b + c = 100 1 ≦ d ≦ 10

M preferably contains Fe as a main component. X ¹
Has an effect of improving the corrosion resistance by mainly forming a solid solution in the crystal, and has an effect of controlling the grain shape of the crystal grains in the diffusion process in the crystal and the reaction process with A. Amount of X ¹ is too low saturation magnetic flux density exceeds 26 atomic%, also 0.1
No effect is obtained with an addition amount of less than atomic%. Further, Z ¹ has a function of making the magnetostriction positive, and is effective in controlling the corrosion resistance and the grain shape similarly to the additive element X ¹ . When the amount of addition of Z ¹ is 0.1 atomic% or more, the effect is exhibited, but when it exceeds 5 atomic%, not only does the saturation magnetic flux density decrease, but also, for example, when a film is formed by a sputtering method, In some cases, formation of a preferable crystal grain structure becomes difficult. The elements X ¹ and Z ¹ basically have the same function in corrosion resistance and grain shape control. However, the diffusion rate, the free energy of oxide or nitride formation, the critical nucleus size of the reaction product, For example, when the magnetic thin film of the present invention is formed by a sputtering method, a reaction process having a plurality of intermediate reactions occurs in the heat treatment immediately after the film formation. Therefore, even when the amount of the additive itself is smaller than that of the magnetic thin film having a single reaction process, the heat treatment stability is improved. A is from 1 atomic% or more to 10%.
In the range of atomic%, the preferred crystal grain structure of the present invention is formed.
Alternatively, deterioration of corrosion resistance and magnetic properties due to the reaction with the preferred amounts of X ¹ and Z ¹ elements dissolved in the crystal grains, and deterioration of soft magnetic properties due to an increase in the solid solution amount of the element A in the crystal grains are also considered. Invite. This magnetic film is preferably formed into a magnetic thin film by appropriately combining with the above-described underlayer, barrier layer or substrate.

Another structure of the magnetic thin film of the present invention is as follows.
(M _a X ² _b Z ² _c ) A magnetic film having a composition represented by _{100-d Ad} .

Here, M is at least one magnetic metal element selected from Fe, Co and Ni, and X ² is S
at least one element selected from i and Ge, Z ² is at least one element selected from the group IVa, Va, Al, Ga and Cr, and A is at least one element of O and N And a, b, c and d are
It is a numerical value satisfying the following relational expression.

0.1 ≦ b ≦ 23 0.1 ≦ c ≦ 8 a + b + c = 100 1 ≦ d ≦ 10

M preferably contains Fe as a main component. X ²
Is mainly dissolved in the crystal to adjust the magnetostriction constant to positive or negative, not only to reduce the crystal magnetic anisotropy of the magnetic crystal, but also to improve the corrosion resistance, and to improve the diffusion process in the crystal. Further, in the course of the reaction with A, there is an effect of controlling the grain shape of the crystal grains. Amount of X ² is too low saturation magnetic flux density exceeds 23 atomic%, also not effective in amount less than 0.1 atom%. Further, Z ² has a function of making magnetostriction positive, and has an effect of controlling corrosion resistance and grain shape similarly to the additive element X ² . The addition amount of Z ² 0.
When the effect is exhibited from 1 atomic% or more, when the atomic concentration exceeds 8 atomic%, not only does the saturation magnetic flux density decrease, but also, for example, when a film is formed by a sputtering method, amorphization proceeds immediately after the film formation, and a preferable crystal grain structure is obtained. May be difficult to form. Element X ² and element Z ² have basically the same function in corrosion resistance and grain shape control, but the diffusion rate, free energy of oxide or nitride formation, and the critical nucleus size of the reaction product Because each is different, for example, when forming the magnetic thin film of the present invention by a sputtering method,
Immediately after the film formation, a reaction process having a plurality of intermediate reactions occurs in the heat treatment. Therefore, even when the amount of the additive itself is smaller than that of the magnetic thin film having a single reaction process, the heat treatment stability is improved. Further, A forms a preferable crystal grain structure in the range of 1 atomic% or more to 10 atomic%, but if it exceeds 10 atomic%, it promotes amorphization immediately after film formation or forms a solid solution in the crystal grains. This leads to deterioration of corrosion resistance and magnetic properties due to the reaction with the preferable amounts of X ² and Z ² elements, and further to deterioration of soft magnetic properties due to an increase in the solid solution amount of the element A in the crystal grains. This magnetic film is preferably formed into a magnetic thin film by appropriately combining with the above-described underlayer, barrier layer or substrate.

Another structure of the magnetic thin film of the present invention is (Fe _a
Si _b Al _c T _d), characterized in that it comprises a magnetic film having a composition represented by _100-e N _e.

Here, T is at least one element selected from Ti and Ta, and a, b, c, d and e are numerical values satisfying the following relational expressions.

10 ≦ b ≦ 23 0.1 ≦ d ≦ 5 0.1 ≦ c + d ≦ 8 a + b + c + d = 100 1 ≦ e ≦ 10

Here, magnetic crystal grains having a shape having a large surface area per volume such as a columnar shape, a needle shape, or a multi-branched shape are mainly formed of FeSi, and the grain boundaries are formed of Al—N, Ta.
It is considered that a reaction product having a small free energy of nitride formation, such as (Ti) -N or Si-N, is formed.

When Si is dissolved in Fe and is ordered, b2
Alternatively, it is known that taking a Do3 structure has an effect of lowering the crystal magnetic anisotropy. However, in the case of the present invention in particular, as a result of structural analysis by X-rays, those diffraction lines have not been confirmed. However, it has been confirmed that when other elements are fixed and the amount of Si is changed in the above range, the magnetostriction changes from positive to negative. Therefore, it is presumed that the FeSi alloy mainly comprising the magnetic crystal grains of the present invention has slightly lower crystal magnetic anisotropy although the degree of order is low.
In the above range of the Si content, T (Ta, Ti) is 0.1.
If it is less than atomic%, the effect of improving corrosion resistance and magnetic properties is obtained, but the effect of improving thermal stability is weak. If it exceeds 5 atomic%, the saturation magnetic flux density decreases. On the other hand, if the sum of Al and T exceeds 8 atomic%, the saturation magnetic flux density decreases and the magnetostriction constant increases, which is not preferable. This magnetic film is preferably a magnetic thin film by appropriately combining with the above-described underlayer, barrier layer or substrate.

Another structure of the magnetic thin film of the present invention is as follows.
_{(Fe a Si b Al c Ti} d) characterized in that it comprises a magnetic film having a composition represented by the _100-ef N _e O _f.

10 ≦ b ≦ 23 0.1 ≦ d ≦ 5 0.1 ≦ c + d ≦ 8 a + b + c + d = 100 1 ≦ e + f ≦ 10 0.1 ≦ f ≦ 5

The magnetic crystal grains having a shape having a large surface area per volume, such as columnar, acicular, or multi-branched, are mainly formed of FeSi, and Al-N, Al-
It is considered that a reaction product having a low free energy of nitride formation, such as O, Ti-N, Ti-O, SiN, or Si-O, is formed. When the content of Ti is less than 0.1 atomic% in the above-mentioned range of the Si content, the effect of improving corrosion resistance and magnetic properties is obtained, but the effect of improving thermal stability is weak. If it exceeds 5 atomic%, the saturation magnetic flux density decreases. If the sum of Al and Ti exceeds 8 atomic%, the saturation magnetic flux density decreases and the magnetostriction constant increases, which is not preferable. N is an element that is effective even when used alone, but especially when combined with O,
Further, the magnetic properties are improved. This is considered to be an effect due to an increase in reaction products. O is added in an amount of 0.1.
At less than 1 atomic%, the effect is not clear, and at 5 atomic%
If more is added, the saturation magnetic flux density deteriorates and the magnetostriction constant increases. This magnetic film is preferably formed into a magnetic thin film by appropriately combining with the above-described underlayer, barrier layer or substrate.

The magnetic thin film has a high saturation magnetic flux density and a high magnetic permeability, and is excellent in heat treatment stability and corrosion resistance, and can be applied to various magnetic devices. In particular, it is preferably used for a magnetic head that requires a recording capability on a medium having a high coercive force, high reproduction sensitivity, and environmental resistance.

[0092]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic thin film having the structure and composition of the present invention can be formed in a low gas pressure atmosphere. For example, high frequency magnetron sputtering, DC sputtering, facing target sputtering, ion beam sputtering, ECR The film can be formed by a sputtering method represented by sputtering or the like. In particular,
An alloy target whose composition is determined in consideration of a composition deviation from the composition of the magnetic film of the present invention is sputtered in an inert gas to form a film on a substrate, and an additional element pellet is arranged on a metal target. The film formation may be performed by simultaneously sputtering to form a film, or by introducing a part of the additive in a gas state into the apparatus and performing reactive sputtering to form a film. At this time, by changing discharge gas pressure, discharge power, substrate temperature, substrate bias state, magnetic field value on the target and near the substrate, target shape, direction of particle incidence on the substrate, etc. The film structure, thermal expansion coefficient, film characteristics depending on the substrate and the target position can be controlled.

Also, thermal evaporation, ion plating, cluster ion beam evaporation, reactive evaporation, EB evaporation, M
It is also possible to form a magnetic thin film by a vapor deposition method typified by BE or a super-quenching method.

As a substrate to be used, for example, it is preferable to use a ferrite substrate when processing the magnetic film of the present invention into a MIG head, and to use a non-magnetic insulating substrate when processing the magnetic film into a LAM head. Each substrate may be formed with an underlayer or a barrier film in advance for the purpose of preventing the reaction between the substrate and the magnetic film, controlling the crystal state, and the like, if necessary.

When a magnetic thin film is used as a magnetic head, the head processing required for the magnetic head process of each shape is performed. The magnetic characteristics of the magnetic film are measured under the heat treatment conditions of the head processing. Will be. By controlling the film forming process, all the magnetic films having the compositions in the following examples show soft magnetic characteristics immediately after film formation, and the magnetic thin film of the present invention can be used even when used in a low temperature forming process such as a thin film head. it can.

[0096]

EXAMPLES In the following examples, the film structure was measured by X-ray diffraction (XR).
D), transmission electron microscope (TEM), and high-resolution scanning electron microscope (HR-SEM). The magnetic crystal grains described in the examples refer to continuous crystal regions that can be considered to have crystallographically substantially the same crystal orientation mainly by comparing a bright-field image and a dark-field image of a TEM. Composition analysis is EP
MA, RBS (Razaford backscattering analysis), especially the composition of the micro-region is determined by EDS with TEM,
The coercive force is BH loop tracer and the saturation magnetic flux density is VSM
And the corrosion resistance was evaluated according to the salt spray test method according to JIS C0024, or by immersing the sample in pure water. Hereinafter, details of the embodiment of the present invention will be described.

Example 1 In Example 1, the film structure such as the composition and crystal shape was changed by changing the sputtering conditions such as the discharge gas pressure and the substrate temperature, the added elements, and the reaction gas flow ratio by using the RF magnetron sputtering method. This is the result of the examination. The results are summarized in (Table 1) to (Table 3). The cross section of the film had a structure in which magnetic crystal grains that could be regarded as substantially needle-like or column-like were grown almost perpendicular to the substrate surface, as shown in a schematic TEM cross-sectional view shown in FIG.

The crystal shape was evaluated based on the average size dL in the longitudinal direction of the crystal grains and the average size dS in the lateral direction. The size in the longitudinal direction was estimated by SEM observation of a fractured surface parallel to the grain growth direction of the film, or TEM observation after ion-milling the polished surface. However, since it is difficult to observe a film section completely parallel to the grain growth direction, the actual dL may be strictly longer than the value in the table. Is determined as the average size dL. Also, the size dS in the short direction is the widest width in the area where the cross section is observed in consideration of the difficulty in observing a completely parallel cross section of the film and the shape of the crystal grains as described above. The average value of the group of crystal grains having is adopted. The thickness of the following samples is 3 μm, and the magnetic properties are the values after heat treatment at 520 ° C. in vacuum.

The film forming conditions in Example 1 are shown below. Examples aa-az, ba-bz conditions Substrate: non-magnetic ceramic substrate Substrate temperature: room temperature Magnetic film target: composite target in which element or compound chip is arranged on Fe target Target size: 3 Inch Discharge gas pressure: 1 to 4 mTorr Sputtering main gas: Ar Nitrogen flow ratio: 2 to 4% Oxygen flow ratio: 0.5 to 2% Discharge power: 400 W Also compared by changing the following conditions from the above example conditions An example experiment was performed.・ Comparison example ca to cc conditions Substrate temperature: changed from room temperature to 300 ° C. ・ Comparative example cd to bf conditions Discharge gas pressure: changed from 1 to 4 mTorr → 8 to 12 mTorr ・ Comparative example cg to ch conditions Nitrogen flow ratio: 2 to 4 % → Changed from 5 to 7% Oxygen flow ratio: changed from 0.5 to 2% to 2 to 7%

[0100]

[Table 1]

[0101]

[Table 2]

[0102]

[Table 3]

In the above examples, when O and N were partially or completely substituted with B and C, almost the same correlation between the magnetic properties and the crystal structure was obtained.

In each of the samples in the examples, the crystal orientation of adjacent magnetic crystal grains was random in the in-plane direction.

When the magnetic film of the above embodiment was manufactured by DC magnetron sputtering, the discharge gas pressure was set to 0.5 to
It was confirmed that almost the same composition and crystal structure can be obtained by changing the input power to 2 mTorr and the input power to 100 W, and that excellent soft magnetic properties are exhibited immediately after film formation.

When the film structure of each of the samples of the above embodiments was observed on a plane parallel to the substrate surface, a deformed circular shape was observed.
It has a deformed elliptical shape or a structure in which these shapes are combined, and the average surface area Sa with respect to the average volume Va of the magnetic crystal grains sufficiently satisfies the relationship of Sa> 4.84 Va ^2/3 . It was confirmed that.

When the samples of the above Examples and Comparative Examples were immersed in pure water for 6 hours, the samples of Comparative Examples ca to cf were corroded until the substrate surface was visible, whereas the samples of the Examples were not corroded. Although it was seen, it did not lead to complete corrosion. Also, the samples of Comparative Examples cg and ch had the best corrosion resistance, but the reduction of the saturation magnetic flux density was remarkably large among all the samples.

Example 2 In Example 2, the RF magnetron sputtering method was used, and sputtering conditions such as discharge gas pressure, substrate temperature, target shape, direction of incident particles, film structure such as crystal shape, and magnetic properties were used. This is the result of examining the relationship. The results are summarized in (Table 4) and (Table 5).

As for the evaluation of the crystal shape, the average size in the longitudinal direction of the crystal grains is dL and the average size in the short direction is dS for the magnetic crystal grains having a substantially columnar or needle-like shape.
Notation. Further, regarding the magnetic crystal grains having a multi-branched shape obtained by combining the substantially columnar portion and the substantially needle-shaped portion, the short direction of each portion is ds, and the maximum length of the multi-branched magnetic crystal grain is dl.
And The measuring method of dL, dS, ds and dl is the same as in the first embodiment. The thickness of the following sample is 3
In μm, the magnetic properties are values after heat treatment at 520 ° C. in vacuum.

The film forming conditions in Example 2 are shown below. Examples aa to ag conditions Substrate: non-magnetic ceramic substrate Substrate temperature: water cooled to 250 ° C. Magnetic film target: FeAlSiTi alloy target Target size: 3 inches Discharge gas pressure: 1 to 4 mTorr Sputtering main gas: Ar Nitrogen flow ratio: 2 to 4% Oxygen flow ratio: 0.5 to 2% Discharge power: 400 W A comparative example experiment was performed by changing the following conditions from the above-described example aa to ag conditions. Comparative Example ca-ce conditions The above substrate temperature: changed to 300 ° C or liquid nitrogen cooling. Example ba-bg conditions Substrate: non-magnetic ceramic substrate Substrate temperature: water-cooled to 250 ° C Magnetic film target: FeAlSiTi alloy target Target size: 5 inches × 15 inches Discharge gas pressure: 1 to 4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 2 to 4% Oxygen flow ratio: 0.5 to 2% Discharge power: 2 kW A comparative example experiment was performed by changing the following conditions from the conditions of ~ bz.・ Comparison Examples da to de Conditions The above substrate temperature: changed to 300 ° C. or liquid nitrogen cooling

[0111]

[Table 4]

[0112]

[Table 5]

In the embodiments aa to ag described above, FIG.
As shown in the schematic TEM cross-sectional view shown in FIG. 3, the magnetic crystal grains had a substantially columnar or substantially needle-like crystal grain as a mother phase, and had a structure grown in a direction substantially perpendicular to the substrate. On the other hand, Examples bb to b
g, the magnetic crystal grains are substantially columnar or substantially needle-shaped crystal grains and multi-branched crystal grains in which two or more substantially columnar or substantially needle-shaped parts are joined, as shown in the schematic TEM cross-sectional view shown in FIG. Was used as a mother phase. This is shown in Examples aa to a
This is probably because the target size was larger than that of g, so that many oblique particles were incident on the substrate, and the growth conditions of the crystal grains were changed. Note that the above-mentioned multi-branched shape can be realized even by using a means in which the angle of incidence of particles incident on the substrate changes periodically, for example, a method of forming a film while changing the positional relationship between the substrate and the target. confirmed.

As in Example 1, when the film structure of any of the samples of Example 2 was observed in a plane parallel to the substrate surface, a deformed circle, a deformed ellipse, or a combination of these shapes was observed. And the average surface area Sa with respect to the average volume Va of the magnetic crystal grains is sufficiently larger than Sa>
It was confirmed that the relationship of 4.84 Va ^2/3 was satisfied.

In the comparative sample, (1) dl> 5
0 nm, (2) 5 nm <dS <60 nm (3) dL> 1
Magnetic properties are poor for those that do not satisfy any of the conditions of 00 nm.

[0116] The composition of samples of Examples and Comparative _{Examples, (Fe a Si b Al c} Ti d) 100-ef N e O f
In the formula, a is 75 to 77 and b is 18 to 2.
1, c is 1-4, d is 1-4, e is 1-2, f is 4-9
Was in the range. When substantially the same film structure was formed under the same film forming conditions, a change in the magnetic properties as observed between the above-described example and the comparative example was not observed with a composition change in this range.

Further, when O and N in Example 2 are partially or completely substituted with B and C, or by changing the target size and the like with the same composition as the composition prepared in Example 1, the film structure can be changed. Even in the case of a multi-branched shape, excellent magnetic characteristics were obtained within the above-mentioned preferable range of the crystal grain size.

In each of the samples in the examples, the crystal orientation of adjacent magnetic crystal grains was random in the in-plane direction.

When the magnetic film of the above embodiment was manufactured by DC magnetron sputtering, the discharge gas pressure was set to 0.5 to
It was confirmed that almost the same composition and crystal structure can be obtained by changing the input power to 2 mTorr and the input power to 100 W, and that excellent soft magnetic properties are exhibited immediately after film formation.

The samples of the above-mentioned Examples and Comparative Examples were used in 0.1.
When immersed in 5N salt water for 50 hours, the comparative sample slightly discolored on the film surface or the membrane substrate interface, whereas the sample in the example did not change.

Example 3 In Example 3, the film structure such as the composition and the crystal shape was changed by changing the sputtering conditions such as the discharge gas pressure and the substrate temperature, the added elements and the reaction gas flow ratio by using the RF magnetron sputtering method. This is the result of the examination. The results are summarized in (Table 6).

As described above, the crystal grain shape and grain boundary state
It was estimated by performing TEM observation of the film cross section and the film parallel plane. The average shortest thickness T of the crystal grain boundary compound is also a value estimated from TEM observation. The thickness of the following samples was 3
μm.

The film forming conditions of the third embodiment are shown below. -Sample a to i conditions Substrate: non-magnetic ceramic substrate Substrate temperature: room temperature Magnetic film target: composite target in which element or compound chip is arranged on Fe target Target size: 3 inches Discharge gas pressure: 2 to 4 mTorr Sputtering main gas: Ar Nitrogen flow ratio: 2 to 4% Oxygen flow ratio: 0.5 to 2% Discharge power: 400 W Heat treatment temperature in vacuum: 500 ° C. The above conditions are further changed by changing the following conditions. An experiment was performed. -Sample j to r conditions: Heat treatment temperature in vacuum: changed from 500 ° C to 600 ° C

[0124]

[Table 6]

In the above embodiment, the crystal grain sizes are all within the above-mentioned preferred crystal grain size range.
The difference in magnetic properties is considered to be due to the thickness of the grain boundary compound. Similar correlation between the magnetic properties and the grain boundary structure was also obtained when O and N in Examples were partially or entirely substituted with B and C.

The samples of Examples a to i of Example 3 showed no corrosion even after immersion in pure water for 24 hours. Examples aa to a in the case where corrosion was confirmed in pure water (Example 1)
The az sample and the samples a to i in Example 3 did not show any fundamental differences such as the structure of the crystal grains and the size of the grain boundary compound, but were examined by EDS accompanying TEM. In the aa to az crystal grains, almost no element having lower free energy of oxide or nitride formation than Fe was recognized, whereas in Examples a to i, more than 10 atomic% or more existed. It was confirmed that.

Further, the same effect can be obtained even when the magnetic film of the present embodiment is formed by a sputtering method having a large amount of oblique incident components so that the crystal grains have a multi-branched shape having the preferred size described above. Was confirmed.

When the magnetic film of the above embodiment was manufactured by DC magnetron sputtering, the discharge gas pressure was set to 0.5 to
It was confirmed that almost the same composition and crystal structure can be obtained by changing the input power to 2 mTorr and the input power to 100 W, and that excellent soft magnetic properties are exhibited immediately after film formation.

Example 4 In Example 4, various base films were formed on a substrate by using an RF magnetron sputtering method.
This is a result of forming a magnetic film under the same conditions thereon and examining the film structure and magnetic characteristics. The results are summarized in (Table 7).
Example, both Comparative Examples were used were formed in the same conditions _{(Fe 80 Si 17 Al 1 Nb} 2) 94 O 1 N 5 as the magnetic film.

The conditions for forming the magnetic film are shown below. Magnetic film deposition conditions Substrate temperature: room temperature Magnetic film target: composite target in which element chips are arranged on Fe target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputtering main gas: Ar Nitrogen flow rate Ratio: 2% Oxygen flow rate ratio: 0.5% Discharge power: 400 W The crystal state of the magnetic film was examined using XRD. The thickness of the following samples was 1 μm, and the magnetic characteristics in the table were as follows:
The value after heat treatment at 500 ° C. for 30 minutes in vacuum.

The conditions for forming the underlayer are shown below. -Base film deposition conditions Substrate: non-magnetic ceramic substrate Substrate temperature: room temperature Base film target: element or compound target on Fe target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputtering main gas: Ar Nitrogen flow ratio: 0 to 20% Oxygen flow ratio: 0 to 20% Discharge power: 100 W The thickness of the base film is 2 nm.

[0132]

[Table 7]

Since the surface free energy varies depending on the measurement method, the table shows the surface free energy of Fe.
Only the magnitude relationship with the value is shown. From the results of XRD and TEM analysis, it is considered that grain growth is remarkable in the samples r to v, which causes deterioration of magnetic characteristics. The base film has a high amorphous ratio and is represented by a molecular formula for convenience, but actually deviates from the exact stoichiometric composition.
Further, in order to examine the effect of the present example, the magnetic characteristics of samples a and i were examined using a single crystal substrate of MgO and an alumina substrate, respectively, and it was confirmed that the magnetic characteristics were further improved in each case. In addition, it was also confirmed that the underlayer film of this example has the same effect even with the other magnetic thin films having the above-described preferable crystal grain structure.

Example 5 In Example 5, various base films were formed on a substrate by using an RF magnetron sputtering method.
This is a result of forming a magnetic film under the same conditions thereon and examining the reaction between the substrate and the film. The results are summarized in (Table 8). Example, using the comparative examples both were formed under the same conditions as in Example 4 as a magnetic film _{(Fe 80 Si 17 Al 1 Nb} 2) 94 O 1 N 5.

The conditions for forming the magnetic film are shown below. Magnetic film deposition conditions Substrate temperature: room temperature Magnetic film target: composite target in which element chips are arranged on Fe target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputtering main gas: Ar Nitrogen flow rate Ratio: 2% Oxygen flow rate ratio: 0.5% Discharge power: 400 W The conditions for forming the underlayer are shown below. Underlayer film formation conditions Substrate: ferrite substrate Substrate temperature: room temperature Underlayer target: element or compound target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0 to 20 % Oxygen flow rate ratio: 0 to 20% Discharge power: 100 W As a base film of each of the samples a to k, first, a film of a single element shown in the table is formed to a thickness of 1 nm on a ferrite substrate, and then an oxide of the same element is formed. , Carbide, and nitride to a thickness of 1 nm. The base films of Samples l to v were formed by forming only oxides, nitrides, and carbides of the same element to a thickness of 2 nm.

After forming the underlayer, alumina was formed to a thickness of 15 nm for the magnetic film and then to a thickness of 5 nm as an antioxidant film, followed by heat treatment at 700 ° C., and the discoloration state of the film surface caused the reaction between the ferrite substrate and the film. The presence or absence was checked.

[0137]

[Table 8]

As can be seen from the table, the adoption of the underlayer structure of the samples a to k can suppress the interdiffusion with the film even when a substrate such as ferrite which reacts easily is used. When a magnetic film was formed to a thickness of 3 μm on the underlying film having the structure of Samples a to k, almost the same magnetic characteristics as in Example 4 were obtained.

Further, it was confirmed that the same effect can be obtained even when the magnetic film of the present example is formed by the sputtering method having a large amount of obliquely incident components so as to have the above-described preferred multi-branched crystal grains. .

Example 6 In Example 6, various base films were formed on a substrate by using an RF magnetron sputtering method.
This is a result of forming a magnetic film under the same conditions thereon and examining the film structure and magnetic characteristics. The results are summarized in (Table 9).
In both the examples and comparative examples, (Fe ₇₉ Si ₁₇ Al ₁ Ta ₃ ) ₉₂ N ₈ formed under the same conditions as the magnetic film was used.

The conditions for forming the magnetic film are shown below. Magnetic film deposition conditions Substrate temperature: room temperature Magnetic film target: composite target in which element chips are arranged on Fe target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputtering main gas: Ar Nitrogen flow rate Ratio: 4% Discharge power: 400 W The crystal state of the magnetic film was examined using XRD. The thickness of the following samples was 1 μm, and the magnetic characteristics in the table were as follows:
The value after heat treatment at 500 ° C. for 30 minutes in vacuum.

The conditions for forming the underlayer are shown below. -Underlayer film formation conditions Substrate: non-magnetic ceramic substrate Substrate temperature: room temperature Underlayer target: target of each element Size: 3 inches Discharge gas pressure: 4 mTorr Sputter gas: Ar Discharge power: 100 W The thickness of the base film is 2 nm.

[0143]

[Table 9]

From the results of XRD and TEM analysis, it is considered that grain growth is remarkable in samples ru to u, which is a cause of deterioration of magnetic characteristics. It has been confirmed that the underlayers of the samples a to j can exert the effect even with other magnetic thin films having the above-mentioned preferable crystal grain structure. In the above embodiment, the substrate was formed directly on the substrate. However, by interposing a thin film made of a compound such as an oxide, carbide, nitride, or boride between the substrate and the substrate, the interface reaction between the substrate and the film was performed. It was also confirmed that can be suppressed.

Example 7 In Example 7, various base films were formed on a substrate by using an RF magnetron sputtering method.
This is the result of forming a magnetic film thereon and examining the film structure and magnetic characteristics. The results are summarized in (Table 10). Example,
The Comparative Example was used _{(Fe 75 Si 20 Al 3 Ti} 2) 94 O 1 N 5.

The conditions for forming the magnetic film are shown below. Magnetic film deposition conditions Substrate temperature: room temperature Magnetic film target: FeSiAlTi alloy target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 2% Oxygen flow ratio: 0. The total film thickness of the samples having a discharge power of 5% or less at 5% is 3 μm, and the magnetic properties in the table are the values after heat treatment at 500 ° C. for 30 minutes in vacuum. Hereinafter, the base films of the samples a to o are referred to as base films a to o (in the case of a multilayer film, a ₁ , a _2, ... From the substrate side).

The underlying films a to c are formed on the substrate by the barrier films a ₁ to a ₁ .
alumina is formed in a thickness of 4nm as c _1, then the same data as the magnetic film as a base film a ₂ to c ₂ - using a get, A
r + nitrogen gas or Ar + oxygen gas, thickness 0.5
A nitride layer or an oxide layer having a thickness of 10 nm to 10 nm was formed.

The conditions for forming the underlying films a to c are shown below. Base film a to c film formation conditions Substrate: ferrite substrate Substrate temperature: room temperature Base film and barrier film target: alumina target FeSiAlTi alloy target target size: 3 inches Discharge gas pressure: 4 mTorr Sputter gas: ( Ar (at the time of forming an alumina layer) Ar (at the time of forming a nitride layer) Ar + N ₂ ; N ₂ flow ratio 15% (at the time of forming an oxide layer) Ar + O ₂ ; O ₂ flow ratio 10% Discharge power: 100 W alumina was formed to a thickness of 4nm as film d ₁ to l _1, then the sub-magnetic layer d ₂ to l ₂ as thick under the same conditions and the magnetic film is 0.3nm~200nm
Formed to have a, then the same data as the magnetic film as the dividing d ₃ to l ₃ - to form an oxide layer with a thickness of 0.03~15nm in using get Ar + O ₂ gas atmosphere.

The conditions for forming the underlying films d to l are shown below. -Base film d to l deposition conditions Substrate: ferrite substrate Substrate temperature: room temperature Base film and barrier film target: alumina target FeSiAlTi alloy target target size: 3 inches Discharge gas pressure: 4 mTorr Sputter gas: ( Ar (when forming an auxiliary magnetic layer) Ar + O ₂ + N ₂ ; O ₂ flow ratio 0.5% N ₂ flow ratio 2% (when separating faults are formed) Ar + O ₂ ; O ₂ flow ratio 5% Discharge power: ( Alumina, when forming a tomographic layer) 100 W (when forming a sub-magnetic layer) 300 W Also, as base films m and n, alumina is formed as a barrier film m ₁ and n ₁ on a substrate to a thickness of 4 nm, and then a sub-magnetic layer m ₂ is formed. ~
n ₂ is the same as the main magnetic film (Fe ₇₅ Si ₂₀ Al ₃ Ti ₂ )
₉₄ O ₁ N ₅ is formed to a thickness of 10 nm or 100 nm, and then a silicon nitride layer is formed to a thickness of 2 nm in an Ar + O ₂ gas atmosphere using a silicon nitride target as the dividing layers l _{3 to} n _3.
Formed.

The conditions for forming the underlying films d to k are shown below. Base film d to k film formation conditions Substrate: ferrite substrate Substrate temperature: room temperature Base film and barrier film target: alumina target FeSiAlTi alloy target Si ₃ N ₄ target Target size: 3 inches Discharge gas Pressure: 4 mTorr Sputter gas: (at the time of forming alumina) Ar (at the time of forming the sub-magnetic layer) Ar + O ₂ + N ₂ ; O ₂ flow ratio 0.5% N ₂ flow ratio 2% (at the time of forming a minute fault) Ar + N ₂ ; N ₂ flow Ratio 10% Discharge power: (Alumina, when forming a tomographic layer) 100 W (When forming a sub-magnetic layer) 300 W As the underlayer o, only 4 nm-thick alumina was formed as a barrier film on a substrate.

The conditions for forming the underlayer o are as follows. -Base film o film forming conditions Substrate: ferrite substrate Substrate temperature: room temperature Barrier film target: alumina target Target size: 3 inches Discharge gas pressure: 4 mTorr Sputter gas: Ar Discharge power: 100 W

[0152]

[Table 10]

In this embodiment, the film itself has the above-mentioned preferred crystal grain structure and composition, so that excellent magnetic properties are maintained. However, the samples a to c, e, and g to n further The characteristics are improved. Note that the sample j marked with * has a thickness of 15 nm for the dividing layer, and when used as a metal material of a MIG head, for example, there is a possibility that the separating layer may cause a pseudo gap. However, there is no problem when used for a LAM type head. Also,*
The sample 1 marked with * has a low coercive force, but has a stepped hysteresis curve. When used in a MIG head, the magnetic characteristics of the sub-magnetic layer are not preferable because they determine the head output. However, there is no problem when used as a LAM head.

The underlayer structure of this embodiment has the effect of improving the magnetic characteristics as in this embodiment as long as the magnetic film has a preferable structure or a preferable composition according to the present invention. The composition that can be used for the base film is not particularly limited. For example, the same effect can be obtained by using any other oxide, nitride, carbide, or boride instead of alumina. . In the case of the samples a to c, the oxides and nitrides of the magnetic film target are used, but borides and carbides may be used. In samples e to n, the same magnetic film as the main magnetic layer was formed as the sub magnetic layer. However, the same effect can be obtained with a metal magnetic layer. Although the oxide or silicon nitride of the main magnetic layer was used as the dividing film,
It has been confirmed that similar effects can be obtained with amorphous, metal, and nonmetal elements having a different crystal structure from the main magnetic layer.

Example 8 Example 8 is a result of examining magnetic properties by using an RF magnetron sputtering method while changing an additive element and a reactant gas flow ratio. The results are summarized in (Table 11). The thickness of the following samples is 3 μm, and the magnetic properties are the values after heat treatment at 520 ° C. in vacuum.

The conditions for forming the magnetic film are shown below. -Magnetic film deposition conditions Substrate: Non-magnetic ceramic substrate Substrate temperature: Room temperature Magnetic film target: Composite target in which element or compound chip is arranged on Fe target Target size: 3 inches Discharge gas pressure: 1-4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0-8% Discharge power: 400 W

[0157]

[Table 11]

A salt spray test according to JIS standards was performed on all of the above samples, and all the samples shown as examples showed good corrosion resistance.

Comparative Example ag had the same composition as that of Example ah except for nitrogen, and showed lower corrosion resistance than ah, despite the absence of nitrogen and the large number of corrosion-resistant elements present in the magnetic crystal grains. Thus, the addition of a small amount of nitrogen is effective for improving the corrosion resistance. Comparative example ac showed good magnetic properties at a heat treatment temperature of about 400 ° C.
At ℃, it deteriorated as indicated. On the other hand, in Example ae, it was confirmed that the heat treatment stability of the magnetic properties was improved due to the Ta effect of the trace addition.

In Example aa marked with *, both the soft magnetic properties and the corrosion resistance were good, but the saturation magnetic flux density was as low as 1 T or less.
However, the saturation magnetic flux density is higher than that of ferrite, and has the most excellent corrosion resistance, so that it has sufficient characteristics for applications such as magnetic coils. In Example bd marked with **, the soft magnetic properties were good, but slight corrosion was observed in the salt spray test.
However, it has a performance that can be sufficiently used for an indoor stationary VTR or a hard desk, which does not require relatively high environmental resistance. In addition, when the FeSiAiTaN material described in the present embodiment is formed on the preferable underlayer of the present invention, the magnetic characteristics are further improved.

Further, even if the magnetic film of this embodiment is formed by a sputtering method having a large amount of oblique incident components so that the crystal grain shape becomes the above-described multi-branched shape having a preferable size,
It was confirmed that a similar effect was obtained.

Example 9 Example 9 is a result of examining magnetic properties by using an RF magnetron sputtering method while changing an additive element and a reactant gas flow ratio. The results are summarized in (Table 12). The thickness of the following samples is 3 μm, and the magnetic properties are the values after heat treatment at 520 ° C. in vacuum.

The conditions for forming the magnetic film are shown below. -Magnetic film deposition conditions Substrate: Non-magnetic ceramic substrate Substrate temperature: Room temperature Magnetic film target: Composite target in which element or compound chip is arranged on Fe target Target size: 3 inches Discharge gas pressure: 1-4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0-8% Discharge power: 400 W

[0164]

[Table 12]

A salt spray test according to the JIS standard was performed on all of the above samples, and all the samples shown in the examples showed good corrosion resistance. As in Example 8, a comparison between Comparative Example ag and Example ah showed that the addition of a small amount of nitrogen was effective in improving corrosion resistance. Further, a comparison between Comparative Example ac and Example ae shows that the heat treatment stability of the magnetic properties is improved due to the effect of a small amount of Ti added.

In Example aa marked with *, the soft magnetic properties and the corrosion resistance were both good, but the saturation magnetic flux density was as low as 1 T or less. However, the saturation magnetic flux density is higher than that of ferrite, and has the most excellent corrosion resistance, so that it has sufficient characteristics for applications such as magnetic coils. Also, the embodiment bd marked with **
Showed good soft magnetic properties but slightly corroded in salt spray test. However, it has a performance that can be sufficiently used for an indoor stationary VTR or a hard desk, which does not require relatively high environmental resistance. Further, the FeSiAiT described in this embodiment is used.
The magnetic properties are further improved by forming the iN material on the above-mentioned preferable underlayer.

In the above (Embodiment 8), Ta was used in this embodiment and Ti was used. However, Ta or Ti was used in Zr, Hf,
V, Nb, Cr, at least one selected from the group and partially or entirely substituted, or Si as Ge, Al as Ga
Alternatively, it was confirmed that even when Cr was partially or entirely substituted with Cr, it also had excellent corrosion resistance and magnetic properties.

Further, it is confirmed that the same effect can be obtained even when the magnetic grains of the present embodiment are formed by the sputtering method having a large amount of oblique incident components so that the crystal grains have the above-described multi-branched shape having a preferable size. Was.

Example 10 Example 10 is a result of examining magnetic properties by using an RF magnetron sputtering method while changing an additive element and a reactant gas flow ratio. Results (Table 13) ~
The results are summarized in (Table 15). The thickness of the following samples is 3 μm, and the magnetic properties are the values after heat treatment at 520 ° C. in vacuum.

The conditions for forming the magnetic film are shown below. -Magnetic film deposition conditions Substrate: Non-magnetic ceramic substrate Substrate temperature: Room temperature Magnetic film target: Composite target in which element or compound chip is arranged on Fe target Target size: 3 inches Discharge gas pressure: 1-4 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0-8% Oxygen flow ratio: 0.5-2% Discharge power: 400W

[0171]

[Table 13]

[0172]

[Table 14]

[0173]

[Table 15]

A salt spray test according to JIS standards was performed on all of the above samples, and all the samples shown in the examples showed good corrosion resistance. Example 9 and Example 10 investigate the magnetic properties when the added light element is nitrogen or nitrogen + oxygen, respectively. Comparing both examples, the overall results show that nitrogen +
It can be seen that the magnetic properties are improved by adding oxygen.

Examples aa and ab marked with * have good soft magnetic properties and corrosion resistance, but have a low saturation magnetic flux density of 1 T or less. However, the saturation magnetic flux density is higher than that of ferrite, and since it has the best corrosion resistance, it has sufficient characteristics for applications such as magnetic coils. In addition, the embodiment bd marked with **
Showed good soft magnetic properties but slightly corroded in salt spray test. However, it has a performance that can be sufficiently used for an indoor stationary VTR or a hard desk, which does not require relatively high environmental resistance. Further, the FeSiAi described in this embodiment is used.
The magnetic properties are further improved by forming the TiON material on the above-mentioned preferable underlayer.

In this embodiment, Ti, Ta, Zr, Hf, V,
Even if it is partially or wholly substituted with at least one selected from Nb and Cr, or if it is partly or wholly substituted with Si for Ge and Al or Ga or Cr, it also has excellent corrosion resistance and magnetic properties. Was confirmed.

Further, it is confirmed that the same effect can be obtained even when the magnetic grains of the present embodiment are formed by the sputtering method having a large amount of obliquely incident components so that the crystal grains have the above-described multi-segmented shape having a preferable size. Was.

(Embodiment 11) In general, corrosion of a metal magnetic film formed on a ferrite proceeds due to a local battery effect with the ferrite, a gap effect at a film interface, and the like, causing a temporal change as a magnetic head. In Example 11,
In order to confirm the reliability as a magnetic head, a prototype MIG head was manufactured. First, the self-recording / reproducing characteristics of the prototype MIG head were measured. Then, a salt spray test was performed on the same MIG head, and the magnetic characteristics after the test were measured. I saw a change. As a comparison, a change in characteristics of a MIG head using sendust (FeAlSi underlayer Bi) as a metal core is shown.

The head specifications are shown below. Head specifications Track width: 17 μm Gap depth: 12.5 μm Gap length: 0.2 μm Number of turns N: 16 Barrier film on ferrite: Alumina 4 nm Magnetic film thickness: 4.5 μm C / N characteristics: relative speed = 10 .2m / s recording / reproducing frequency = 20.9MHz tape: MP tape

[0180]

[Table 16]

As described above, when the magnetic film of the present invention is used for a magnetic head, a magnetic head having improved head characteristics and high reliability can be obtained.

Example 12 In Example 12, various underlayers were formed on an uneven substrate by using an RF magnetron sputtering method, and an underlayer that was excellent in suppressing substrate cracking and having excellent magnetic properties was examined. It is a thing.

On a 2 mm × 28 mm × 1 mt ferrite substrate, 15 μm × 2 mm × 15 μmt unevenness
A crack test substrate processed in 00 pieces was prepared. On this test substrate, an alumina barrier film was formed to a thickness of 3 nm, and subsequently, various underlayers formed by controlling the crystal grain size by changing the amount of addition of nitrogen, oxygen, Nb, Y or Hf to 100 nm were formed. An FeSiAlTiON film was formed to a thickness of 10 μm on the top. After heat-treating this magnetic thin film at 520 ° C., only the film was removed by chemical etching, and the crack ratio of the uneven substrate portion was examined. On the other hand, on a flat glass substrate, each underlayer monolayer was formed to 3 μm, and the average crystal grain size after heat treatment was determined by XRD.
I checked in. Table 17 shows the cracking rate and the average crystal grain size.

The conditions for forming the underlayer are shown below. -Nitrogen-added underlayer film formation conditions Substrate temperature: water cooling Target: FeSiAlTi Target size: 5 x 15 inches Discharge gas pressure: 8 mTorr Sputter main gas: Ar Nitrogen flow ratio: 2 to 20% Oxygen flow ratio: 0% Discharge power: 2 kW Oxygen-added underlayer film formation conditions Substrate temperature: water-cooled Target: FeSiAlTi Target size: 5 × 15 inches Discharge gas pressure: 8 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0% Oxygen flow ratio: 2 to 10% Discharge power: 2 kW ・ Nb, Y or Hf-added underlayer film formation conditions Substrate temperature: water-cooled Target: FeSiAl target with a plurality of 10 mm square Nb, Y, or Hf chips mounted thereon -Target Target size: 5 x 15 inches Discharge gas pressure: 8 mTorr Sputter main gas: Ar Nitrogen flow ratio: 0% Oxygen flow ratio: 0% Discharge power: 2 kW

[0185]

[Table 17]

From the above examples, it can be seen that the substrate crack can be suppressed when the average crystal grain size is 20 nm or less regardless of the material of the base film.

Based on the above results, the nitrogen-added substrate 100 having the above-mentioned average crystal grain size of 30 nm or 20 nm was used.
The following MIG head was prototyped using nm. The results are summarized in (Table 18).

The head specifications are shown below. Head specifications Track width: 17 μm Gap depth: 12.5 μm Gap length: 0.2 μm Number of turns N: 16 Barrier film on ferrite: Alumina 3 nm Magnetic film thickness: 9 μm C / N characteristics: Relative speed = 10.2 m / S recording / reproducing frequency = 20.9 MHz tape: MP tape

[0189]

[Table 18]

It can be seen that the characteristics of the magnetic head are improved when the underlying film is within the preferred range of the present invention.

Next, on the underlayer 100 nm, which was refined to 20 nm by addition of nitrogen, which was effective in (Table 18), an underlayer with an increased amount of nitrogen added was increased to 2 nm so as to further reduce the particle size to 2 nm. A head was formed under the same conditions as described above. Similarly, on the underlayer 100 nm, which has been further miniaturized to 20 nm by addition of nitrogen, an underlayer with a gradually reduced nitrogen addition amount of 30 nm is formed to the nitrogen addition amount of the magnetic thin film to be further formed. did. The results are shown in (Table 19).

[0192]

[Table 19]

It can be seen that the characteristics of the magnetic head are further improved when the underlying film is in the above-mentioned preferable range.

Next, when the miniaturized underlayer (micromagnetic layer) shown in the example of (Table 17) was immersed in 0.5 N salt water for 100 hours, the crystal grain size was reduced to about 5 nm. Although slight interfacial corrosion was observed in the obtained nitrogen-added film and oxygen-added film, the sample of the micronized underlayer formed by adding the elements of the IIIa group (Y), the IVa group (Hf), and the Va group (Nb) was not used at all. No corrosion was seen.

Next, in order to determine the optimum thickness of the underlayer, the cracking rate was examined by changing the thickness of the underlayer of the nitrogen-added material from 1 to 500 nm, and the results are shown in Table 20. The conditions for forming the nitrogen-added underlayer were selected so that the average crystal grain size was 20 nm.

[0196]

[Table 20]

From the above examples, the preferred thickness of the fine magnetic layer is 10 nm or more, and the more preferred thickness is 30 nm.
It turns out that it is 0 nm or more. In this embodiment,
Although a ferrite was used as the substrate and a magnetic material was used as the film, the miniaturized underlayer of the present invention is basically effective for the entire thin film in which internal stress exists.

[0198]

As described above, according to the magnetic thin film of the present invention, the total amount of interfacial energy per unit volume is smaller than that of a conventional microcrystalline material having a small average crystal grain size. Grain growth is suppressed, and soft magnetic characteristics can be stabilized in a wide temperature range. In addition, the magnetic film
Since it is crystalline immediately after film formation, it does not require a large amount of additives for amorphization, and therefore can have a high saturation magnetic flux density. obtain. In addition, depending on the size of the crystal grains, a magnetic film that is less corroded by a local battery and has excellent corrosion resistance can be obtained.

Further, according to a preferred embodiment of the present invention in which the underlayer between the substrate and the magnetic film includes a micronized layer, regardless of the surface state or shape of the substrate, film peeling and substrate destruction are suppressed. There is an effect that formation can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a magnetic film having multi-branched crystal grains as viewed from a film growth direction (however, a base film and a substrate are omitted).

FIG. 2 is a schematic view of a magnetic film having columnar or needle-like crystal grains as viewed from the film growth direction (however, a base film and a substrate are omitted).

Claims (38)

[Claims] 1. A magnetic thin film including a magnetic film having a magnetic crystal grain as a mother phase in which an average volume Va and an average surface area Sa satisfy the following relational expression. Sa> 4.84Va ^2/3 2. The magnetic thin film according to claim 1, wherein the magnetic crystal grains have an average maximum length exceeding 50 nm. 3. The magnetic crystal grain is formed of a substantially needle-like body, a substantially columnar body, or a multi-branched body composed of a combination thereof, and the average crystal size of the substantially needle-like body or the substantially columnar body in the lateral direction is reduced. The magnetic thin film according to claim 2, wherein the magnetic thin film is larger than 5 nm and smaller than 60 nm. 4. A substantially needle-like or substantially columnar magnetic crystal grain is used as a parent phase, and the average crystal size dS in the lateral direction and the average crystal size dL in the longitudinal direction of the magnetic crystal grain satisfy the following relational expressions, respectively. A magnetic thin film comprising a magnetic film. 5 nm <dS <60 nm dL> 100 nm 5. An average crystal size ds in a lateral direction of said substantially needle-like body or said substantially columnar body, wherein a magnetic crystal grain including a polybranched crystal comprising a combination of substantially needle-like body or substantially columnar body is used as a mother phase. And a magnetic thin film wherein the average maximum length dl of the multi-branched crystal includes a magnetic film satisfying the following relational expression. 5 nm <ds <60 nm dl> 50 nm 6. The magnetic thin film according to claim 1, wherein crystal orientations of adjacent magnetic crystal grains are different at least in an in-plane direction. 7. The method according to claim 1, comprising at least one light element selected from C, B, O and N, and an element having a lower free energy of oxide and / or nitride formation than Fe.
7. The magnetic thin film according to any one of items 1 to 6, 8. The magnetic thin film according to claim 1, wherein the magnetic crystal grains contain an element having a lower free energy of oxide and / or nitride formation than Fe. 9. An element having a lower free energy of oxide and / or nitride formation than Fe is at least one element selected from the group consisting of group IVa element, group Va element, Al, Ga, Si, Ge and Cr. A magnetic thin film according to claim 7 or 8. 10. The microcrystalline or amorphous grain boundary compound comprising at least one selected from carbides, borides, oxides, nitrides and metals is contained in the grain boundaries of the magnetic crystal grains. 10. The magnetic thin film according to any one of 9. 11. The magnetic thin film according to claim 10, wherein assuming that the average shortest length of the grain boundary compound is T, the average shortest length T of at least 30% of the grain boundary compound satisfies the following relational expression. 0.1 nm ≦ T ≦ 3 nm 12. An underlayer comprising at least one underlayer and a magnetic film formed on the underlayer, wherein at least one layer constituting the underlayer has an oxide and / or iron rather than Fe.
The magnetic thin film according to any one of claims 1 to 11, further comprising an element having a low free energy of nitride formation. 13. An underlayer comprising at least one layer and a magnetic film formed on the underlayer, wherein at least one of the layers constituting the underlayer that is in contact with the magnetic film comprises:
The magnetic thin film according to any one of claims 1 to 12, comprising a substance having a lower surface free energy than Fe. 14. An underlayer comprising at least one layer, and a magnetic film formed on the underlayer, wherein at least one of the layers constituting the underlayer is in contact with the magnetic film,
Al, Ba, Ca, Mg, Si, Ti, V, Zn, Ga
The magnetic thin film according to any one of claims 1 to 13, wherein the magnetic thin film is any compound selected from carbide, oxide, nitride, and boride of at least one element selected from Zr and Zr. 15. An underlayer comprising at least one layer and a magnetic film formed on the underlayer, wherein at least one of the layers constituting the underlayer that is in contact with the magnetic film comprises:
C, Al, Si, Ag, Cu, Cr, Mg, Au, Ga
The magnetic thin film according to any one of claims 1 to 13, comprising at least one substance selected from Zn and Zn. 16. An underlayer A comprising at least one underlayer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and an underlayer B in contact with the underlayer A Wherein the underlayer B is Al, Ba, Ca,
It is made of at least one material selected from Mg, Si, Ti, V, Zn, Ga and Zr, and the underlayer A is selected from carbides, oxides, nitrides and borides of the material constituting the underlayer B. The magnetic thin film according to claim 1, comprising a compound. 17. An underlayer including at least one underlayer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and an underlayer B is in contact with the underlayer A Wherein the underlayer A is Al, Ba, Ca,
The underlayer B is selected from carbides, oxides, nitrides, and borides of the material constituting the underlayer A, which is made of at least one material selected from Mg, Si, Ti, V, Zn, Ga, and Zr. The magnetic thin film according to claim 1, comprising a compound. 18. An underlayer A including at least one underlayer, and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and an underlayer B is in contact with the underlayer A. Wherein the underlayer A is at least one element selected from main constituent elements contained in the magnetic film;
At least one element selected from oxygen and nitrogen and containing more oxygen or nitrogen than the magnetic film, wherein the underlayer B is any compound selected from carbide, oxide, nitride and boride Claim 1 which consists of
14. The magnetic thin film according to any of 13. 19. An underlayer A comprising at least one underlayer, and a magnetic film as a main magnetic layer formed on the underlayer, wherein the underlayer is in contact with the magnetic film and the underlayer A And the underlayer A is formed by alternately laminating at least one sub-magnetic layer and at least one split layer, and the underlayer B is selected from oxides, nitrides, carbides, and borides. 2. The method according to claim 1, comprising any one of the compounds.
14. The magnetic thin film according to any one of items 13 to 13. 20. The magnetic thin film according to claim 19, wherein the dividing layer shares at least one element with the magnetic film and contains more oxygen or nitrogen than the magnetic film. 21. The magnetic thin film according to claim 19, wherein the thickness t _M of the sub-magnetic layer and the thickness t _S of the split layer satisfy the following relational expressions, respectively. 0.5 nm ≦ t _M ≦ 100 nm 0.05 nm ≦ t _S ≦ 10 nm 22. An underlayer comprising at least one layer, and a magnetic film formed on the underlayer, wherein at least a layer of the underlayer in contact with the substrate has an amorphous magnetic material or an average particle diameter d. The magnetic thin film according to any one of claims 1 to 21, wherein the magnetic thin film is a fine magnetic layer having a magnetic crystal grain satisfying the following relationship as a mother phase. d ≦ 20 nm 23. the thickness t _r of the fine magnetic layer, the magnetic thin film according to claim 22 in which the thickness t _f of the magnetic film satisfies the respective following relationships. _{10nm <t r <t f /} 3 24. The micro magnetic layer and the magnetic film having at least one
24. The magnetic thin film according to claim 22, wherein the magnetic thin film has a kind of common element. 25. The magnetic thin film according to claim 24, wherein the common element includes an element having the lowest free energy of oxide and / or nitride formation among elements contained in the fine magnetic layer or the magnetic film. 26. The common element is at least one element selected from oxygen, nitrogen, carbon and boron.
26. The magnetic thin film according to 4 or 25. 27. The fine magnetic layer is made of a group IIIa, group IVa, or Va
23. At least one element selected from the group consisting of:
27. The magnetic thin film according to any one of -26. 28. An underlayer including at least one underlayer, and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and an underlayer is in contact with the underlayer. hints, the oxygen in the magnetic film, nitrogen, element group concentration C ₁ (atomic weight%) consisting of carbon and boron, oxygen of the underlying layer a, nitrogen, element group concentration C ₂ consisting of carbon and boron (atomic weight% ), Oxygen and nitrogen in the underlayer B,
Magnetic thin film according to any one of claims 22 to 27 element group concentration C ₃ consisting of carbon and boron (atomic weight%) satisfy the following relational expression. 0 ≦ C ₁ ≦ C ₃ <C ₂ 29. An underlayer A having at least one underlayer and a magnetic film formed on the underlayer, wherein the underlayer is in contact with the magnetic film and an underlayer B is in contact with the underlayer A hints, the oxygen in the magnetic film, nitrogen, element group concentration C ₁ (atomic weight%) consisting of carbon and boron, oxygen of the underlying layer a, nitrogen, element group concentration C ₂ consisting of carbon and boron (atomic weight% ), Oxygen and nitrogen in the underlayer B,
Magnetic thin film according to any one of claims 22 to 27 element group concentration C ₃ consisting of carbon and boron (atomic weight%) satisfy the following relational expression. 0 ≦ C ₁ ≦ C ₂ ≦ C ₃ 30. The element group concentration C ₁ is different from the element group concentration C _3, and the element group concentration C ₂ changes almost continuously in the film thickness direction so as to reduce the concentration difference at the layer interface.
3. The magnetic thin film according to 1. 31. The magnetic thin film according to claim 22, which is formed on a substrate having irregularities. 32. The magnetic thin film according to claim 12, which is formed on a high-resistance substrate or a high-resistance material. 33. A magnetic thin film formed on a substrate having a barrier layer formed thereon, wherein the barrier layer is made of Al, Si, C
a thickness du composed of an oxide or nitride of at least one element selected from r and Zr, and satisfying the following relational expression:
The magnetic thin film according to any one of claims 10 to 32, comprising: 0.5 nm <du <10 nm 34. _{^{(M a X 1 b Z 1}} c) magnetic thin film comprising a magnetic film having a composition represented by _100-d A _d. Here, M is at least one magnetic metal element selected from Fe, Co and Ni, and X ¹ is Si, Al, Ga and Ge
At least one element selected from, Z ¹ is IVa
A is at least one element selected from the group consisting of Group V, Group Va and Cr, A is at least one element of O and N, and a, b, c and d are numerical values satisfying the following relational expressions. 0.1 ≦ b ≦ 26 0.1 ≦ c ≦ 5 a + b + c = 100 1 ≦ d ≦ 10 35. _{^{(M a X 2 b Z 2}} c) magnetic thin film comprising a magnetic film having a composition represented by _100-d A _d. Here, M is at least one kind of magnetic metal element selected from Fe, Co and Ni, X ² is at least one kind of element selected from Si and Ge, and Z ² is IVa group, Va group, A
At least one element selected from l, Ga and Cr, A is at least one element of O and N, and a, b, c and d are numerical values satisfying the following relational expressions. 0.1 ≦ b ≦ 23 0.1 ≦ c ≦ 8 a + b + c = 100 1 ≦ d ≦ 10 36. _{(Fe a Si b Al c T} d) magnetic thin film comprising a magnetic film having a composition represented by _100-e N e. Here, T is at least one element selected from Ti and Ta, and a, b, c, d and e are numerical values satisfying the following relational expressions. 10 ≦ b ≦ 23 0.1 ≦ d ≦ 5 0.1 ≦ c + d ≦ 8 a + b + c + d = 100 1 ≦ e ≦ 10 37. _{(Fe a Si b Al c Ti} d) 100-ef N e
Magnetic thin film comprising a magnetic film having a composition represented by O _f. Here, a, b, c, d, e and f are numerical values satisfying the following relational expressions. 10 ≦ b ≦ 23 0.1 ≦ d ≦ 5 0.1 ≦ c + d ≦ 8 a + b + c + d = 100 1 ≦ e + f ≦ 10 0.1 ≦ f ≦ 5 38. A magnetic device comprising the magnetic thin film according to claim 1 as a component.