JPH05251235A - Soft magnetic alloy film and magnetic head - Google Patents

Abstract

PURPOSE:To realize a soft magnetic alloy film for magnetic head use, which not only shows good soft magnetic characteristics and a high saturation magnetization after a high-temperature heat treatment is performed but also shows a low magnetostriction and a good surface state, and a magnetic head which is formed at a high yield using this alloy film. CONSTITUTION:The composition of a soft magnetic alloy film is modulated in the film thickness direction in at least the time of formation of the alloy film and is an Fe composition modulated nitride film with a mean composition, which is shown by a formula FeaTibZrcNd (a, b, c, and d represent atomic % and are respectively set on the condition of 70<=a<=92, 1<=b<=6, 3<=c<=10, 3<=d<=20 and a+b+c+d=100, in the film. A magnetic cap is attached to a magnetic head with high-melting point glass and a head chip is attached to a non-magnetic support with low-melting point glass. The magnetic head is a metal-in cap type magnetic head (an MIG head) formed using the above soft magnetic alloy film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a video tape recorder.
The present invention relates to an Fe-based soft magnetic alloy film suitable as a core material for a magnetic head such as a (VTR) or a hard disk, and a magnetic head using the core material for a magnetic head.

[0002]

2. Description of the Related Art When manufacturing a practical magnetic head, it is important to firmly bond the magnetic gap and the like with an adhesive glass or the like from the viewpoint of reliability and the like. Since the adhesive glass having a high adhesive strength generally has a high melting point, a highly reliable magnetic head can be manufactured with a high yield by forming a high temperature gap using the adhesive glass having a high melting point. In this case, the soft magnetic alloy film for a magnetic head needs to have good soft magnetic characteristics after high temperature heat treatment. In particular, in a magnetic head that undergoes a step in which a heat treatment is further applied after forming a magnetic gap by glass bonding, an adhesive glass having an extremely high melting point is used to prevent the magnetic gap from loosening due to a heat treatment in a later step. Must be formed. As such a magnetic head, for example, in a metal-in-gap type magnetic head (hereinafter referred to as MIG head) in which a magnetic path is formed by a soft magnetic alloy film and ferrite arranged near the gap, a glass having a high melting point of 650 ° C. or higher is used. There is a structure in which the head chip with the gap formed is embedded in a non-magnetic support of a slider for a hard disk with a glass having a low melting point of 600 ° C. or less. The soft magnetic alloy films used for these are required to show good magnetic properties after heat treatment at an extremely high temperature of 650 ° C. or higher. Typical soft magnetic alloys used as core materials for magnetic heads include Co-based amorphous alloys, sendust, etc., and higher saturation magnetization is required as the magnetic recording density increases. .. However, in consideration of the thermal stability of the soft magnetic characteristics described above, in the conventional soft magnetic alloy film for a magnetic head such as a VTR, the practical upper limit of saturation magnetization is a Co-based amorphous alloy or sendust. It was around 1T (Tesla) achieved.

[0003]

As a soft magnetic alloy film for a magnetic head used for high density recording, a soft magnetic alloy film having a saturation magnetization as high as possible is required. A Fe-based composition-modulated nitrided alloy film, which has been developed previously and whose nitrogen composition is modulated in the film thickness direction (for example, Japanese Patent Application No. 61-54054 and Japanese Patent Application No. 1-54054).
-25008 and Japanese Patent Application No. 1-300506) have a high saturation magnetization exceeding 1T and exhibit good soft magnetic properties after high-temperature heat treatment, and are therefore suitable materials for magnetic heads. However, in the Fe-based composition-modulated nitride film, the magnetic characteristics change depending on the heat treatment temperature, so it is necessary to select an appropriate composition according to the heat treatment temperature. Even when such an Fe-based composition-modulated nitride film is used as a core material for a magnetic head to which a high-temperature heat treatment is applied, a composition which is non-magnetostrictive after the high-temperature heat treatment or a composition which hardly causes surface oxidation by the high-temperature heat treatment is used. I had to clarify. According to the present invention, in a Fe-based composition-modulated nitride alloy film obtained by applying composition modulation by nitrogen to a Fe-based alloy, not only good soft magnetic characteristics and high saturation magnetization but also low magnetostriction are obtained after heat treatment at high temperature. It is an object of the present invention to provide a soft magnetic alloy film for a magnetic head which hardly causes surface oxidation, and a magnetic head which uses the same and has good head characteristics and can be manufactured with a high yield.

[0004]

In order to achieve the above object, in the soft magnetic alloy film of the present invention, the composition in the film thickness direction is modulated at least when the alloy film is formed, and the average composition in the film is represented by the formula Fe _a Ti _b Zr _c N _d , in the composition of the above formula,
Fe is iron, Ti is titanium, Zr is zirconium, N is nitrogen, and a, b, c, and d represent atomic%, and each is 7
0 ≦ a ≦ 92, 1 ≦ b ≦ 6, 3 ≦ c ≦ 10, 3 ≦ d ≦ 20, a
A soft magnetic alloy film with + b + c + d = 100 is used. In this case, at least the composition of nitrogen is modulated in the film thickness direction, and the average composition in the film is represented by the formula Fe _a Ti _b Zr _c N _d , where Fe is iron and Ti is titanium. , Z
r is zirconium, N is nitrogen, and a, b, c, d
Represents atomic% and 70 ≦ a ≦ 92, 1 ≦ b ≦ 6, respectively.
A soft magnetic alloy film containing 3 ≦ c ≦ 10, 3 ≦ d ≦ 20, a + b + c + d = 100, and Fe-based fine crystal grains may be used. In the above cases, the soft magnetic alloy film having a composition modulation wavelength of 60 nm or less in the film thickness direction is particularly excellent in soft magnetic characteristics. Further, as a magnetic head, a magnetic path is formed by at least the vicinity of the gap and is composed of a soft magnetic alloy film and ferrite, and at least the nitrogen composition is modulated in the film thickness direction of the soft magnetic alloy film. The composition is the formula Fe _a Ti
_b Zr _c N _d , wherein Fe is iron,
Ti is titanium, Zr is zirconium, N is nitrogen,
a, b, c, d represent atomic% and 70 ≦ a ≦ 9, respectively
2, 1 ≤ b ≤ 6, 3 ≤ c ≤ 10, 3 ≤ d ≤ 20, a + b + c
+ D = 100, and a magnetic head which is a soft magnetic alloy film containing Fe-based fine crystal grains is used. Here, the magnetic head is arranged at least in the vicinity of the gap to form a magnetic path with the soft magnetic alloy film and ferrite, the high melting glass adheres the magnetic gap, and the low melting glass adheres the head chip to the non-magnetic support. In the above magnetic head, the soft magnetic alloy film is such that at least the composition of nitrogen is modulated in the film thickness direction, and the average composition in the film is represented by the formula Fe _a Ti _b Z
indicated by r _c N _d, in the composition of the formula, Fe is iron, Ti
Is titanium, Zr is zirconium, N is nitrogen,
a, b, c, d represent atomic% and 70 ≦ a ≦ 9, respectively
2, 1 ≤ b ≤ 6, 3 ≤ c ≤ 10, 3 ≤ d ≤ 20, a + b + c
+ D = 100, and it is particularly effective to use a magnetic head which is a soft magnetic alloy film containing Fe-based fine crystal grains.

[0005]

The soft magnetic alloy film of the present invention contains a metal element having a strong affinity for nitrogen in the Fe-based alloy, and it is clear that the composition of at least the nitrogen element was modulated in the film thickness direction immediately after the alloy film was formed by the sputtering method. The composition-modulated nitride alloy film has a different composition-modulated structure, that is, a laminated structure including a nitride layer and a non-nitride layer. Here, in the composition-modulated nitride alloy film, the composition of the nitrogen element is modulated, so that the other constituent elements are also relatively composition-modulated. The sum of the layer thicknesses of the nitrided layer and the non-nitrided layer in the film thickness direction is called the composition modulation wavelength, which is controlled by changing the mixing period of the nitrogen gas mixed in the sputtering gas during sputtering. .. The ratio of the nitrogen gas mixed in the sputtering gas is shown by using a nitrogen gas partial pressure ratio Pn (%) expressed by Pn (%) = 100 × (nitrogen gas partial pressure) / (total sputtering gas pressure). The composition-modulated nitride alloy film thus produced exhibits a clear composition-modulated structure at the time of film formation and is in an amorphous state or in a state close to that. The modulation structure shifts to an indefinite composition modulation structure, and after high-temperature heat treatment, Fe-based fine crystal grains such as α-Fe are contained. In the state where the structure of the alloy film is changed by this heat treatment, the soft magnetic alloy film of the present invention has not only good soft magnetic characteristics and high saturation magnetization but also low magnetostriction. Therefore, the conditions for obtaining good soft magnetic properties after heat treatment are
It is necessary that at least the composition of nitrogen element is modulated at the time of forming the alloy film by the sputtering method, or that the composition of nitrogen is slightly modified in the film thickness direction after the heat treatment to contain Fe-based fine crystal grains. That is why. Here, in order to obtain particularly excellent soft magnetic characteristics, the composition modulation wavelength should be at least 60 nm or less.

In the soft magnetic alloy film of the present invention, Fe, which has a weak affinity for the nitrogen element, and Zr and Ti, which have a strong affinity for the nitrogen element, coexist in the alloy film. In the alloy film, Zr or the like is selectively chemically strongly bonded to the nitrogen element, which is important for obtaining a thermally stable and good soft magnetic property after the heat treatment. In the soft magnetic alloy film of the present invention, in order to simply obtain high saturation magnetization and good soft magnetic properties after high temperature heat treatment, the average composition Zr in the film should be at least 3.
Atomic% or more, nitrogen 3 atomic% or more, conversely Fe 92 atomic%
In order to increase the saturation magnetization, it is preferable that the Fe content is at least 60 atomic% or more, Zr is at least 20 atomic% or less, and nitrogen is 20 atomic% or less. The above average composition in the film is basically F
Although it is composed of three elements, e, Zr and N, this ternary alloy film has a drawback that surface oxidation is likely to occur due to high temperature heat treatment in consideration of practical characteristics. It has been found that adding 1 atomic% or more of Ti is effective as a method for suppressing the surface oxidation during the high temperature heat treatment. However, if the addition amount of Ti is excessively increased to about 10 atomic% or more, surface oxidation is recognized again, and in this sense, the Ti content must be 1 atomic% or more and 10 atomic% or less. Furthermore this T
It was confirmed that the quaternary soft magnetic alloy film containing i was reduced in magnetostriction particularly by high temperature heat treatment at 650 ° C. or higher. 650-7
In order to obtain a soft magnetic alloy film having a low magnetostriction after heat treatment at about 20 ° C., the Ti content must be 6 atomic% or less in terms of the average composition in the film. If the amount of Ti increases more than this, the magnetostriction increases to the positive side. The composition of these is the composition formula shown in the scope of the claims. The soft magnetic alloy film of the present invention obtained as described above has a composition having good soft magnetic characteristics and high saturation magnetization after high-temperature heat treatment, has low magnetostriction, and has a composition in which surface oxidation hardly occurs even by high-temperature heat treatment. ing. However, even if a part of Fe is replaced with Co or Ni, it is only necessary that Fe is the main component, and if the sputtering gas contains an unavoidable gas, etc., and the alloy film contains oxygen, etc. If so, there is no problem. The above soft magnetic alloy film of the present invention is particularly effective for high-temperature heat treatment at 650 ° C. or higher, and is suitable for a magnetic head that requires heat treatment at such an extremely high temperature. There is. As described above, the magnetic head using the high temperature heat treatment is a MIG head having a soft magnetic alloy film arranged at least in the vicinity of the gap, and the magnetic gap is adhered by the high melting point glass and the head chip is made of a non-magnetic support by the low melting point glass. It is particularly effective to use a structure adhered to. This is because the soft magnetic alloy film exhibits good magnetic properties and practical properties after heat treatment at an extremely high temperature, so that a magnetic gap can be connected by a strong glass having an extremely high melting point of 650 ° C. or higher. This prevents the magnetic gap from loosening when bonding with low melting glass, and it is also possible to use low melting glass with relatively strong adhesive strength,
The yield in manufacturing the magnetic head is improved.

[0007]

EXAMPLE A soft magnetic alloy film according to the first example of the present invention will be described below. Fe ₉₀ Ti ₃ Zr _{7 was formed} by the high frequency sputtering method.
Is used as an alloy target, and a nitrogen gas (N ₂ ) of 0.16 Pa is periodically mixed in an argon gas (Ar) of 1.44 Pa at the time of sputtering, and 10 per layer is formed on a ceramic substrate.
A multilayer film in which a nitride layer having a thickness of 10 nm and a non-nitriding layer having a thickness of 10 nm per layer were periodically laminated in the film thickness direction, that is, a composition-modulated nitride alloy film was formed. In this case, the nitrogen gas partial pressure ratio Pn is 10%,
The composition modulation wavelength is 20 nm. The average composition of the composition-modulated nitrided alloy film formed using the above alloy target is Fe.
₈₁ Ti _2.7 Zr _5.3 N _11, and the composition-modulated nitrided alloy film thus formed was subjected to heat treatment in a magnetic field at 670 ° C. for 1 hour in a vacuum with an air pressure of 5 mPa or less to form a soft magnetic alloy film. .. The surface of this soft magnetic alloy film has a beautiful metallic luster, almost no surface oxidation is observed, a low coercive force of 19 A / m and a high relative magnetic permeability of 4400 in the direction of hard magnetic domains,
It had a high saturation magnetization of 1.6T. Further, when the saturation magnetostriction constant λs was measured, it was found to be almost non-magnetostriction (λs = 0), and it was a soft magnetic alloy film for a magnetic head having good magnetic characteristics and practical characteristics. This is the case of a specific heat treatment temperature, but the saturation magnetostriction constant of the composition-modulated nitride alloy film changes depending on the heat treatment temperature. The Fe-based composition-modulated nitrided alloy film tends to change its magnetostriction constant to the negative side as it is subjected to high-temperature heat treatment. In the case of the soft magnetic alloy film of the present invention, 650
It becomes amagnetostrictive after heat treatment at ~ 720 ℃. Table 1 shows the magnetic characteristics when the composition-modulated nitride film was subjected to heat treatment in a magnetic field for 1 hour at each heat treatment temperature.

[0008]

[Table 1]

Table 1 shows Examples 1, 2, and 3 of the present invention by heat treatment at 650 ° C. or higher, and Comparative Examples 4, 5 by heat treatment at 600 ° C. or lower. All of these samples have good soft magnetic properties represented by high saturation magnetization, low coercive force, and high magnetic permeability, but as shown by the saturation magnetostriction constant, they were annealed at a high temperature of 650 ° C or higher. Example 1
2 and 3 have low magnetostriction with an absolute value of 1 × 10 to ⁶ or less.

The soft magnetic alloy film exhibiting low magnetostriction and good soft magnetic characteristics after such a high temperature heat treatment is useful for a magnetic head. Further, the samples in Table 1 show almost no surface oxidation at any heat treatment temperature, as indicated by the surface condition being good (◯). This is Fe-
This is because Ti is added to Zr-N, and Fe-Zr-N
In the ternary system alone, whitening occurs due to surface oxidation after high temperature heat treatment. Similarly, using Fe ₉₀ Ti ₃ Zr ₇ as the alloy target, the nitrogen gas partial pressure ratio Pn is 10%.
As a result, composition-modulated nitride alloy films having various composition-modulation wavelengths were prepared, but the saturation magnetization and the saturation magnetostriction constant did not change much even when the composition-modulation wavelengths were different. But,
The coercive force decreased as the compositional modulation wavelength became shorter, and showed particularly good soft magnetic properties at 60 nm or less. Next, by the high frequency sputtering method, the composition modulation wavelength was 20 nm by changing the ratio of the argon gas partial pressure and the nitrogen gas partial pressure at the time of sputtering so that the total sputtering gas pressure would be 1.6 Pa by using alloy targets of various compositions. A composition-modulated nitrided alloy film was prepared and heat-treated in an optimum magnetic field at a high temperature of 650 to 720 ℃ to prepare a soft magnetic alloy film. Table 2 collectively shows the magnetic properties and surface states of the soft magnetic alloy films having various compositions.

[0011]

[Table 2]

In Table 2, Examples 6, 7 and 8 of the present invention and Comparative Examples 9, 10 and 11 after heat treatment at 650 ° C. or higher are shown.
, The average composition in the film and some magnetic properties are represented by values rounded to the nearest whole number.
From Table 2, in the average composition in the film, Fe-Ti-Zr-
The soft magnetic alloy film made of N has not only high saturation magnetization and good soft magnetic properties, but also low magnetostriction with an absolute value of 1 × 10 to ⁶ or less and a good surface state (○) It can be seen that it exhibits oxidizing properties. On the other hand, Fe-Zr-of the comparative example
The soft magnetic alloy film made of N and Fe-Ti-N has high saturation magnetization and soft magnetic properties, but cannot achieve a low magnetostriction and a good surface state after heat treatment at high temperature.
In particular, Comparative Example 11 shows that when Ti content is too high, surface oxidation occurs, and when Ti is added to Fe-Zr-N, the Ti content is in a suitable composition range, that is, at least 1 atomic%. If the content is 6 atomic% or less, a low magnetostriction and a good surface state will be exhibited. As described above, the soft magnetic alloy film of the present invention is a Fe-based composition-modulated nitride alloy film having a specific composition, and exhibits not only good soft magnetic characteristics and high saturation magnetization but also low magnetostriction after heat treatment at high temperature. Thus, the soft magnetic alloy film for a magnetic head hardly causes surface oxidation.

A magnetic head according to the second embodiment of the present invention will be described below. Using the soft magnetic alloy film of the present invention described in the first embodiment, MIG which is a magnetic head for a hard disk was manufactured as follows. Alumina is deposited to a layer thickness of 10 nm by high frequency sputtering on a ferrite substrate of I-shape and C-shape, which has been subjected to track processing and whose surface facing the gap is mirror-polished, and then continuously deposited in the same vacuum chamber. A Fe-based composition-modulated nitride alloy film was formed on the alumina of 2 to have a thickness of 2 μm. Further, an SiO ₂ layer having a layer thickness of 0.1 μm is formed as a gap material on the Fe-based composition-modulated nitrided alloy film, and a high melting point adhesive glass having a sealing temperature of about 670 ° C. is formed on the SiO ₂ layer by 0.1 μm
m formed. When manufacturing the Fe-based composition modulation nitride film, F
Using e ₉₀ Ti ₃ Zr ₇ as an alloy target, 0.14 Pa nitrogen gas was added to 1.44 Pa argon gas (Ar) during sputtering.
While periodically mixing (N ₂ ), a nitride layer of 10 nm per layer and a non-nitride layer of 10 nm per layer were periodically laminated in the film thickness direction. Alumina in this case was provided to prevent the diffusion of oxygen from the ferrite into the soft magnetic alloy film during heat treatment. The average composition in the soft magnetic alloy film is Fe ₈₁ Ti _2.7 Zr _5.3.
N ₁₁ and the saturation magnetization after this heat treatment is 1.6 T.
The two I-shaped and C-shaped head core halves thus produced were butted against each other with high melting point glass on the magnetic gap surface, and heat-treated in a magnetic field at 670 ° C. for 1 hour to form a head core block. This head core block was cut in a direction substantially perpendicular to the gap surface to obtain a head chip having a head front portion with a track width of 11 μm and a core thickness of 150 μm. This head chip was embedded in a slider for a hard disk which was a non-magnetic support, and was bonded and integrated with a low melting point glass having a sealing temperature of around 550 ° C. Further, the integrated slider was subjected to front surface polishing to regulate the gap depth to 5 μm or less, and then wound, to obtain a magnetic head of the present invention. The magnetic head of the present invention manufactured as described above, that is, the MIG head for a hard disk using the Fe-based composition modulation nitride film of the present invention, has the magnetic gap formed by the high melting point adhesive glass. When the head chip was embedded and adhered to the slider with the low melting point glass, the magnetic gap did not loosen, and a very good yield in manufacturing was obtained. The electromagnetic conversion characteristics of this MIG head were measured using a high coercive force medium, and compared with the MIG head using a sendust alloy film having a saturation magnetization of 1T. The MIG head using the sendust alloy film has good electromagnetic conversion characteristics, but the MIG head using the Fe-based composition modulation nitride film of the present invention has an additional 2 dB compared with this MIG head. The output has been improved as described above, and a good value of 10 dB or more has been shown for the overwrite characteristic. This difference in head output and overwrite characteristics is due to the soft magnetic alloy film of the present invention having high saturation magnetization and high magnetic permeability. Therefore, the magnetic head of the present invention using the soft magnetic alloy film of the present invention is a magnetic head which can be manufactured with high yield and has a high head output.

[0014]

As is apparent from the above examples, the soft magnetic alloy film according to the present invention exhibits not only good soft magnetic characteristics and high saturation magnetization after high temperature heat treatment but also low magnetostriction, and surface oxidation by heat treatment occurs. It is a difficult-to-use soft magnetic alloy film for magnetic heads. Further, the magnetic head using this soft magnetic alloy film has good head characteristics, has the effect of being manufactured with high yield, and is extremely useful.

Claims (5)

[Claims] 1. The composition in the film thickness direction is modulated at least when the alloy film is formed, and the average composition in the film is _expressed by the formula Fe _a Ti _b Zr.
_c N _d , in the composition of the above formula, Fe is iron, Ti
Is titanium, Zr is zirconium, N is nitrogen,
a, b, c, d represent atomic% and 70 ≦ a ≦ 9, respectively
2, 1 ≤ b ≤ 6, 3 ≤ c ≤ 10, 3 ≤ d ≤ 20, a + b + c
Soft magnetic alloy film characterized in that + d = 100. 2. The composition of at least nitrogen is modulated in the film thickness direction, and the average composition in the film is represented by the formula Fe _a Ti _b Zr _c N _d , in which Fe is iron and Ti is Titanium, Zr is zirconium, N is nitrogen, a, b,
c and d represent atomic%, 70 ≦ a ≦ 92, 1 ≦ b, respectively
≦ 6,3 ≦ c ≦ 10, 3 ≦ d ≦ 20, a + b + c + d = 100
And a soft magnetic alloy film containing Fe-based fine crystal grains. 3. The soft magnetic alloy film according to claim 1, wherein the composition modulation wavelength in the film thickness direction is 60 nm or less. 4. A magnetic path is formed at least in the vicinity of the gap by a soft magnetic alloy film and ferrite, and the soft magnetic alloy film has at least the nitrogen composition modulated in the film thickness direction, and the average composition in the film. Is represented by the formula Fe _a Ti _b Zr _c N _d , wherein Fe is iron, Ti is titanium, Z
r is zirconium, N is nitrogen, and a, b, c, d
Represents atomic% and 70 ≦ a ≦ 92, 1 ≦ b ≦ 6, respectively.
A magnetic head which is a soft magnetic alloy film having 3 ≦ c ≦ 10, 3 ≦ d ≦ 20, a + b + c + d = 100 and containing Fe-based fine crystal grains. 5. A magnetic path is formed at least near the gap to form a magnetic path with a soft magnetic alloy film and ferrite, a magnetic gap is adhered with a high melting point glass, and a head chip is adhered to a non-magnetic support with a low melting point glass. In the magnetic head, at least the composition of nitrogen is modulated in the film thickness direction of the soft magnetic alloy film, and the average composition in the film is represented by the formula Fe
_a Ti _b Zr _c N _d , in the composition of the above formula, Fe is iron, Ti is titanium, Zr is zirconium, N is nitrogen, and a, b, c and d are atomic%, respectively. 70 ≦ a
≤ 92, 1 ≤ b ≤ 6, 3 ≤ c ≤ 10, 3 ≤ d ≤ 20, a + b +
A magnetic head which is a soft magnetic alloy film having c + d = 100 and containing Fe-based fine crystal grains.