JP3087265B2 - Magnetic alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic alloy for a magnetic device such as a magnetic head which is particularly suitable for high-density magnetic recording.

[0002]

2. Description of the Related Art In recent years, the need for higher density and broader bandwidth of magnetic recording has increased, and by using a magnetic material having a high coercive force Hc for a magnetic recording medium and narrowing a recording track width, a high density magnetic recording has been achieved. Recording and playback are realized. A magnetic alloy having a high saturation magnetic flux density Bs is required as a magnetic head material for recording and reproducing data on and from a magnetic recording medium having a high coercive force. Or a magnetic head used for all of them has been proposed.

However, the coercive force of the magnetic recording medium has been further increased, and the coercive force of the magnetic recording medium has been increased to, for example, 2000 Oe.
As described above, it has become difficult to perform good magnetic recording and reproduction with a magnetic head using a sendust alloy or an amorphous alloy. In addition, a perpendicular magnetization recording method in which recording is performed by magnetizing the magnetic recording medium not in the longitudinal direction but in the thickness direction has been proposed. However, in order to perform this perpendicular magnetization recording method satisfactorily, the tip of the main pole of the magnetic head is required. The thickness of the part must be 0.5 μm or less,
Recording on a magnetic recording medium having a relatively low coercive force also requires a magnetic alloy for a magnetic head having a high saturation magnetic flux density.

As a magnetic alloy for a magnetic head having a higher saturation magnetic flux density than a sendust alloy or an amorphous alloy, for example, a FeN-based magnetic alloy disclosed in Japanese Patent Application Laid-Open No. 64-42108 is known. I have. Further, as one of the magnetic head structures, there is a magnetic head structure including a glass molding process such as a metal-in-gap (MIG) or a laminated type. These general schematic diagrams are shown in FIGS. 10 and 11, respectively. The low-melting glass used in such a magnetic head has a low melting point of 50 from the viewpoint of reliability such as adhesive strength and weather resistance.
A glass mold at a high temperature of 0 ° C. or higher is required.

Therefore, the core material used in these magnetic heads must have sufficient soft magnetic properties as a magnetic head even at a high temperature of 500 ° C. or higher. The soft magnetic properties required for the magnetic head are sendust alloy (FeAlSi alloy), amorphous alloy or permalloy alloy (Ni
In the case of using Fe alloy) or the like, the magnetic characteristics of the magnetic film formed on the smooth substrate have a coercive force Hc ≦ 0.5 Oe and a magnetic permeability μ ≧ 2000.
If the magnetic properties are inferior to this, a decrease in recording / reproducing efficiency and an increase in noise are caused, and it is difficult to produce a magnetic head having good electromagnetic conversion characteristics. Becomes

[0006]

However, a magnetic alloy disclosed in JP-A-64-42108 as a magnetic alloy for a magnetic head having a higher saturation magnetic flux density than a sendust alloy or an amorphous alloy has a temperature of 500 ° C. or higher. No mention is made of the magnetic properties at high temperatures, and cannot be applied to magnetic heads including a glass molding process. In addition, the present inventors
By selecting N and Si content ratios in the FeN-Si alloy, a soft magnetic alloy for a magnetic head having a high Bs of 15 kG or more was proposed (see JP-A-3-134138 and others).

Among the magnetic alloys according to these proposals are 50.
Even after heat treatment at a high temperature of 0 ° C. or higher, those which maintained excellent soft magnetic properties were included, but the disclosed composition range is based on the properties after heat treatment at 300 ° C.,
It was not guaranteed that good magnetic properties could be obtained even after heat treatment at 500 ° C. or higher within the disclosed composition range.

Accordingly, the present invention provides a soft magnetic alloy having good soft magnetic properties even after heat treatment at a high temperature of 500 ° C. or more and having a high Bs of 15 kG or more, and further provides a soft magnetic alloy in a salt water atmosphere. It is an object of the present invention to provide a soft magnetic alloy having excellent corrosion resistance which hardly causes corrosion even in such a bad environment.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has the following 1) to 3).
The present invention provides a magnetic alloy having the structure described above. 1) Atomic% represented by a composition formula of FeaNbSic and represented by a, b and c is 5 ≦ b ≦ 10 2 ≦ c ≦ 6 a + b + c = 100 and 2.2 ≦ (bc) ≦ 6.0. A magnetic alloy, characterized in that: 2) It is represented by a composition formula of FeaNbSicMd, and a, b,
A magnetic alloy characterized in that the atomic% represented by c and d satisfies 5 ≦ b ≦ 10 2 ≦ c ≦ 60.3 ≦ d ≦ 3 a + b + c + d = 100 and 2.2 ≦ (bc) ≦ 6.0 . (However, M is Mo, Ru, Ti, Cr,
3) The magnetic alloy according to claim 2, wherein M is a mixture of Ru and Mo or a mixture of Ru and Y.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of an apparatus for producing a magnetic alloy for a magnetic head according to the present invention. Reference numerals 5 and 5 denote a pair of targets, each of which is an alloy target of Fe and Si or a composite target in which chip-shaped Si is fitted into a concave portion of a pure iron target provided with an appropriate concave portion. These targets 5,5 are supported by target holders 9,9, and these targets 5,5 and target holders 9,9 are supported.
, A negative potential is applied from a DC power supply 13, and the plasma 1 is
Magnets 6 and 6 for focusing 4 are inserted, and cooling water 8 flows in to prevent the surfaces of targets 5 and 5 from being heated.

Then, on the left and right of the vacuum chamber 15 grounded,
Two target holders 9, 9 are provided insulated by insulators 7, 7. Nitrogen (N ₂ ) and argon (Ar) are introduced from the upper part of the vacuum chamber 15 at a predetermined flow rate by flow meters 1 and 2 respectively. Argon is used to adjust the amount of nitrogen in the magnetic alloy film formed simultaneously with sputtering the targets 5 and 5. A substrate 11 is placed on a substrate holder 12 below the vacuum chamber 15, and a shutter 10 for preventing impurities covers the substrate 11, so that a magnetic alloy manufacturing apparatus is schematically configured.

In operation of the manufacturing apparatus, a plasma 14 is generated between the targets 5 supported by the left and right target holders 9 by the DC power supply 13.
At this time, since the targets 5 and 5 have a negative potential, argon ions (Ar ⁺ ) in the plasma 14 collide with the targets 5 and 5, and iron atoms and Si atoms fly out of the targets 5 and 5. Then, the atoms of iron and Si protruding from the targets 5 and 5 are combined with the atoms or molecules of nitrogen in the plasma to grow a magnetic film on the substrate 11. In addition, by closing the shutter 10 and covering the substrate 11 for a few minutes after the start of sputtering, the impurities on the surfaces of the targets 5 and 5 are prevented from adhering to the substrate 11 and thereafter the shutter 10 is opened. .

[0013] Then, by adjusting the introduced amount of nitrogen and argon by the flow meter 1 can be obtained contained the desired nitrogen Fe _a N _b Si _c alloy. Fe _a
In the case of obtaining the N _b Si _c M _d alloy, it may be used an alloy target element corresponding to the Fe, Si and M (Mo, Ru, etc.). Further, the magnetic alloy of the present invention can also be manufactured by using another film formation method, for example, an RF magnetron sputtering method, an ion beam sputtering method, an EB evaporation method, or the like.

Next, the composition ratio between Si and nitrogen will be described. FIG. 2 is a diagram showing a change in magnetic characteristics with respect to the Si content when the nitrogen amount is fixed. FIG. 3 is a diagram showing a change in magnetic characteristics depending on a heat treatment temperature. FIG. 2 shows the magnetic characteristics at a heat treatment temperature of 550 ° C., where Si is 6 at%.
(Atomic%), Hc is 10 Oe or more. However, as shown in FIG. 3, even when the Si content is 6 at%, a low Hc of 0.5 Oe or less can be obtained when the heat treatment temperature is 500 ° C. FIG. 4 shows the relationship between the Si content and the magnetic properties at a heat treatment temperature of 500 ° C. As can be seen from this figure, when Si is 2 to 6 at%, an excellent soft magnetic film of Hc ≦ 0.5 Oe is obtained, and Bs at this time is 18 kG or more.

FIG. 5 is a diagram showing the relationship between the nitrogen flow rate and Hc, λs (magnetostriction) when forming a magnetic alloy by sputtering. FIG. 6 is a diagram showing the relationship between the nitrogen flow rate and the nitrogen content in the magnetic film after film formation. However, the relationship between the nitrogen flow rate and the nitrogen content in the magnetic film may differ depending on the film forming apparatus used. The nitrogen content was quantitatively analyzed using EPMA (electron probe microanalyzer) and XPS (X-ray photoelectron spectroscopy) using a TiN substrate as a standard sample, and an error of about ± 20% is expected.
FIG. 7 is a diagram in which FIG. 5 is rewritten based on FIG. 6 into changes in Hc and λs with respect to the nitrogen content in the magnetic film. FIG. 8 shows the result when the heat treatment temperature is 500 ° C. From these figures, it can be seen that the nitrogen content is 5 to 11.5.
It can be seen that a magnetic film exhibiting excellent soft magnetic characteristics of Hc ≦ 0.5 Oe can be obtained at at%. Table 1 shows a comparative example of the magnetic permeability μ. As shown in the table, nitrogen content 5-10at%
In this case, a high μ material having μ ≧ 2000 is obtained.

Therefore, the content of Si is 2 to 6 at% and the content of nitrogen is 5 to 6 at%.
When the concentration is 10 at%, H
An excellent soft magnetic alloy for a magnetic head in which c ≦ 0.5 Oe and μ ≧ 2000 is obtained.

[0017]

[Table 1]

Next, the change in the saturation magnetostriction λs of the magnetic film and the change in the magnetic characteristics of the magnetic film before and after the glass mold will be described.
Table 2 is a table showing Hc before and after glass molding in magnetic films having different λs.

[0019]

[Table 2]

When λs is 3 × 10 ⁻⁶ , Hc before glass molding is as low as 0.3 Oe, but 1 Oe after glass molding.
And Hc are increasing. On the other hand, when | λs | ≦ 2 × 10 ⁻⁶ as in Samples 2 to 4, there is almost no deterioration in magnetic properties after glass molding, and a magnetic alloy with Hc ≦ 0.5 Oe can be obtained. Therefore, if a magnetic alloy satisfying | λs | ≦ 2 × 10 ⁻⁶ is used, a high-performance magnetic head that can sufficiently bring out the characteristics of the magnetic alloy serving as a core even in a magnetic head including a glass molding process can be obtained. Obtainable.

In FIG. 7, a region where the nitrogen content where Hc ≦ 0.5 Oe is 5 at% or more and where | λs | ≦ 2 × 10 ^-6 is expressed by the difference between the nitrogen and Si contents is as follows. Become like Here, b and c are the content ratios of nitrogen and Si in FeaNbSic (a + b + c = 100). 2.7 ≤ (bc) ≤ 4.3 for Si 2.3at% 2.7 ≤ (bc) ≤ 6.0 for Si 3.2at% 2.2 ≤ (bc) ≤ 5.5 for Si 6.0at%

Similarly, FIG. 8 in which the heat treatment temperature is 500 ° C. is as follows. 2.7 ≤ (bc) ≤ 6.0 for Si 2.3at% 2.2 ≤ (bc) ≤ 5.3 for Si 3.2at% 2.7 ≤ (bc) ≤ 4.1 for Si 6.0at%

In the case of the heat treatment at 600 ° C., the λs change was almost the same as in FIG. From the above experimental results, 2.2 ≤
(Bc) ≦ 6.0, and Si 2 to 6 at%, N 5 to 10
By setting at%, it is possible to obtain an excellent soft magnetic alloy having Hc ≦ 0.5 Oe, μ ≧ 2000, | λs | ≦ 2 × 10 ⁻⁶ even after heat treatment at 500 ° C. or higher. By using this, it is possible to obtain a high-performance magnetic head with no deterioration in magnetic properties even after the glass molding step.

FIG. 9 shows that magnetic films having different compositions are immersed in 5% salt water, and the ratio of the saturation magnetic flux MS (t) after immersion to the saturation magnetic flux MS (0) before immersion is determined at regular intervals using VSM. It is a measurement result. Although not shown for the sake of simplicity, Fe ₈₈ Si ₄ Cr ₁ N ₇ and Fe ₈₈ Si ₄ Co
₁ for compositions of N ₇ and be subjected to the same experiment, also in this _{case, Fe 88 Si 4 Ru 1 N} 7 and Fe _87.5 Si
Almost the same results as ₄ Ti ₁ Ru _0.5 N ₇ were obtained. In these measurement results, the corrosion resistance is slightly improved by adding Si to FeN, and the corrosion resistance is also improved by adding Zr. However, the difference is small, and when used as a magnetic head, there is a possibility that a problem due to corrosion may occur depending on the environment in which the head is used. However, the present inventors have reported that Mo, R
It has been found that by adding at least one or more elements selected from u, Ti, Cr, Y, and Co, the corrosion resistance is dramatically improved.

Further, Mo, Ru, Ti, Cr, Y, Co
When a mixture of Mo and Ru or a mixture of Y and Ru is selected as a combination of two or more elements selected from the group consisting of, particularly excellent corrosion resistance is obtained, and Sendust which has already been put to practical use in various fields is obtained. It was also found that corrosion resistance almost equivalent to that of the alloy sputtered film was obtained.

Here, Mo, Ru, Ti, Cr, Y, C
The amount of one or more elements selected from o will be described. If the total content of these elements is 0.3 at% or less, no remarkable effect on corrosion resistance is exhibited. For example, as shown in FIG. 9, in the case of Mo 0.2 at%, only corrosion resistance equivalent to that of a magnetic film to which Mo is not added can be obtained.
This was the same for the other elements. On the other hand, if the total amount of these elements exceeds 3 at%, the soft magnetic properties, especially the magnetic properties when the treatment is performed at a high temperature of 500 ° C., will be deteriorated.

Therefore, Mo, Ru, Ti, Cr, Y, C
The total amount of one or more elements selected from o is 0.3 to
When the content is 3 at%, the corrosion resistance can be drastically improved without deteriorating the magnetic properties.

[0028]

According to the magnetic alloy of the present invention, FeaNbS
Atomic% represented by a composition formula of ic and represented by a, b, and c
Since 5 ≦ b ≦ 10, 2 ≦ c ≦ 6, a + b + c = 100, and 2.2 ≦ (bc) ≦ 6.0, 500 ° C.
When a magnetic head is manufactured by performing the above high-temperature treatment, the coercive force Hc ≦ 0.5 Oe, the magnetic permeability μ ≧ 2000, the saturation magnetic flux density Bs is 15 kG or more, and the absolute value | λs of the magnetostriction λs
Good soft magnetic characteristics having | ≦ 2 × 10 -6 without deterioration of magnetic characteristics can be obtained. Further, it is represented by a composition formula of FearNbSicMd, where M is Mo, Ru, Ti, Cr, Y, Co.
When at least one or more elements selected from the following are selected, the atomic% represented by a, b, c, and d is 5 ≦ b ≦ 10;
2 ≦ c ≦ 6, 0.3 ≦ d ≦ 3, a + b + c + d = 10
Since 0 and 2.2 ≦ (bc) ≦ 6.0, the touch resistance is excellent in addition to the above-described effects. Further, when M is a mixture of Ru and Mo or a mixture of Ru and Y,
Excellent touch resistance.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a manufacturing apparatus of a magnetic alloy for a magnetic head according to the present invention.

FIG. 2 is a diagram showing a change in magnetic characteristics with respect to a Si content when a nitrogen amount is fixed.

FIG. 3 is a diagram showing a change in magnetic characteristics depending on a heat treatment temperature.

FIG. 4 is a diagram showing the relationship between the Si content and the magnetic properties when the heat treatment temperature is 500 ° C.

FIG. 5 is a diagram showing the relationship between the nitrogen flow rate and Hc, λs when forming a magnetic alloy by sputtering.

FIG. 6 is a diagram showing a relationship between a nitrogen flow rate and a nitrogen content in a magnetic film after film formation.

7 is a diagram in which FIG. 5 is rewritten based on FIG. 6 into changes in Hc and λs with respect to the nitrogen content in the magnetic film.

FIG. 8 is a diagram showing a result in the case of a heat treatment temperature of 500 ° C. in FIG. 7;

FIG. 9 is a diagram showing a result obtained by immersing magnetic films having different compositions in salt water and measuring a ratio of a saturation magnetic flux after immersion to a saturation magnetic flux before immersion at regular intervals using a VSM.

FIG. 10 is a diagram showing a general example of a metal-in-gap (MIG) type magnetic head.

FIG. 11 is a diagram showing a general example of a laminated type magnetic head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 5 Target 7 Insulator 8 Cooling water 9 Target holder 10 Shutter 12 Substrate holder 13 DC power supply 14 Plasma 15 Vacuum layer

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Kengo Koyanagi (56) References JP-A-63-299219 (JP, A) JP-A-3-134138 (JP, A) JP-A-2-262306 (JP, A) JP-A-2-189906 (JP, A) JP-A-62-89309 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 38/00 303 G11B 5/31 H01F 10/14 H01F 41/18

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein said composition is represented by FeaNbSic.
A magnetic alloy, wherein the atomic percentages represented by b and c are 5 ≦ b ≦ 102 2 ≦ c ≦ 6 a + b + c = 100 and 2.2 ≦ (bc) ≦ 6.0. 2. The composition is represented by a composition formula: FeaNbSicMd.
The atomic% represented by a, b, c, and d is such that 5 ≦ b ≦ 10 2 ≦ c ≦ 6 0.3 ≦ d ≦ 3 a + b + c + d = 100 and 2.2 ≦ (bc) ≦ 6.0. Magnetic alloy. (However, M is Mo, Ru, Ti, Cr,
At least one or more elements selected from Y and Co) 3. The magnetic alloy according to claim 2, wherein M is a mixture of Ru and Mo or a mixture of Ru and Y.