JPS6321746B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Field The present invention relates to a method of heat treatment of amorphous magnetic materials such as those for use in magnetic heads, and has various properties preferable as a soft magnetic material, particularly high magnetic permeability and magnetic permeability in a low measuring magnetic field. The present invention relates to a heat treatment method for amorphous magnetic materials that significantly improves the properties of amorphous magnetic materials. Background technology Conventionally, permalloy, sendust, ferrite, etc. have been used as core materials for magnetic heads, but permalloy has poor wear resistance, and sendust is brittle, so it requires a large number of man-hours to process into a thin plate. In addition, ferrite has a magnetic flux density of about 4000~
There were various problems such as low power of around 5000G. As a magnetic material for a magnetic head that solves this problem, an amorphous magnetic material has been developed that has good soft magnetic properties and has favorable properties such that the eddy current loss is small because it is a foil strip. Various improvements have been proposed for amorphous magnetic materials, such as improving their wear resistance, increasing their magnetic flux density, and increasing their magnetic permeability. For example, JP-A-51-73920, JP-A-59-
Co- disclosed in Publication No. 8048 and put into practical use
Fe-Si-B-based amorphous magnetic materials contain semimetals (metalloids) such as Si and B as amorphous elements, and
It is an amorphous magnetic material (generally called metal-metalloid) containing about 30 atomic percent, but its wear resistance is generally inferior to sendust, and its thermal stability is such that its magnetic permeability initially shows a large value, but There was a problem in that the magnetic head was significantly degraded due to heating and holding at about 100°C for bonding or molding, which is often used when manufacturing magnetic heads. Therefore, amorphous magnetic materials (generally An amorphous material for magnetic heads that has a Co-Zr composition with low magnetostriction and that contains Mo, B, and Ni to improve corrosion resistance, wear resistance, and saturation magnetic flux density. There is a general demand for materials with high magnetic flux density, such as alloys being proposed (Japanese Patent Laid-Open No. 59-38349). By the way, when a magnetic head is assembled using the above-mentioned magnetic materials for magnetic heads and mounted on various recorders, etc., the generally coveted high magnetic flux density material does not necessarily exhibit good mounting characteristics, and the mounting characteristics are considered important. It has recently become known that impedance, bias current value, recording signal current value, playback frequency characteristics, playback sensitivity, etc. greatly depend on the magnetic permeability of the magnetic material used, especially in low magnetic fields. It is receiving particular attention. From the viewpoint of improving the mounting characteristics of such magnetic heads,
When considering Co-based amorphous magnetic materials with high magnetic flux density, magnetic materials that simply have a high saturation magnetic flux density of over 10 kG require a high magnetic field (10 mOe or more).
A relatively good value of magnetic permeability can be obtained at 1 mOe.
The magnetic permeability in a low magnetic field is extremely low compared to that in a high magnetic field, resulting in a problem that, for example, the reproduction sensitivity of a magnetic head for audio recording and reproduction becomes low. Therefore, it is possible to improve the properties of magnetic materials by devising heat treatment methods for amorphous magnetic materials. In either case, heat treatment in a rotating magnetic field is performed because heat treatment below the crystallization temperature and above the Curie temperature is impossible, but when the difference between the crystallization temperature and the Curie temperature is large, Even if heat treatment was performed in a rotating magnetic field at a temperature below the crystallization temperature, no significant improvement in magnetic permeability could be obtained at a low measurement magnetic field. For example, JP-A-1986-
No. 112449, Japanese Unexamined Patent Publication No. 114646. On the other hand, for amorphous magnetic materials whose crystallization temperature is higher than the Curie temperature, the usual heat treatment method is possible, that is, air cooling or water cooling after annealing at a temperature range below the crystallization temperature and above the Curie temperature for the required time. It is well known that Furthermore, it is known that when this method is applied to the above metal-metalloid amorphous magnetic material, a sufficiently high magnetic permeability can be obtained. Furthermore, the metal-metalloid type Co-
As a heat treatment method aimed at reducing D.A (disaccommodation) of Fe-Si-B alloys, a method of applying normal heat treatment and heat treatment in a rotating magnetic field was proposed in JP-A-55-110764. However, the effect of improving magnetic permeability is only around 10%, and as mentioned above, the decrease in magnetic permeability of these alloys when heated to about 100°C to 150°C is extremely large. This was insufficient as a core material for the head. Furthermore, even if metal-metallic amorphous magnetic materials are subjected to heat treatment in the temperature range below the above crystallization temperature and above the Curie temperature for the required time by air-cooling or water-cooling after annealing, metal-metalloid amorphous magnetic materials In some cases, it was difficult to obtain sufficient magnetic permeability compared to highly magnetic materials. In particular, when the magnetic flux density of the metal-metal amorphous magnetic material is approximately 7000G or higher and the crystallization temperature is higher than the Curie temperature, but the temperature difference is narrow, sufficient magnetic permeability cannot be obtained using normal heat treatment methods. There were many cases where it was not possible. Purpose of the Invention The present invention relates to a metal-to-metal type amorphous magnetic material, which has high magnetic permeability, high magnetic permeability, and has various desirable characteristics as a soft magnetic material for a magnetic head, and improves the mounting characteristics of the magnetic head. In particular, the objective is a heat treatment method that can obtain high magnetic permeability in a low measuring magnetic field. Structure and Effects of the Invention From the viewpoint of improving the mounting characteristics of a magnetic head, the present invention is particularly directed to materials having an appropriate high magnetic flux density of about 6000G or more, for example, 0.1 mOe to 3 mOe.
In order to obtain an extremely high magnetic permeability in a low measuring magnetic field, we investigated various heat treatment methods and found that an essentially metal-metal type amorphous material containing only a small amount of metalloids of less than 10 atomic percent or no metalloids was obtained. Since the induced magnetic anisotropy of a high quality alloy is relatively large in a rapidly cooled state, this magnetic anisotropy cannot be completely eliminated even if a heat treatment is used below the crystallization temperature and above the Curie temperature. By means of heat treatment in a rotating magnetic field at 150°C or higher and lower than the Curie temperature, the magnetic anisotropy becomes substantially zero, the coercive force is reduced, and the magnetic permeability, especially the magnetic permeability at a low measurement magnetic field, is reduced to 50% to 300%. It was discovered that it is possible to dramatically improve the performance by more than %. Furthermore, in detail, the above-mentioned Japanese Patent Application Laid-Open No. 55-110764
The Co-Fe-Si-B alloy described in the publication is a metal-metalloid amorphous alloy containing a large amount of semimetal, and has originally low induced magnetic anisotropy, so the temperature is below the crystallization temperature and above the Curie temperature. The magnetic anisotropy becomes virtually zero just by annealing at
The magnetic permeability does not improve much, and the method of this invention can only achieve such a dramatic effect when applied to the metal-metalloid amorphous alloy mentioned above. In addition, from the perspective of improving the mounting characteristics of magnetic heads,
It has a suitably high magnetic flux density of about 6000G or more, and in particular,
In order to obtain a magnetic material that exhibits an extremely high magnetic permeability in a low measurement magnetic field of about 0.1 mOe to 3 mOe, and also has excellent soft magnetic properties that also have corrosion resistance and wear resistance, various combinations of additive elements were investigated. As a result, Ni, Nb, Mo, and B were added to Co and Zr.
An amorphous alloy containing . , while applying a rotating magnetic field relative to the magnetic material, 150
It has been found that by carrying out two-stage heat treatment maintained in the Curie temperature range of 0.degree. That is, the present invention has at least one of Zr, Ti, Hf, Nb, Ta, and Y as a main component of 5 to 20 at% and Co65 to 85 at%, and
Amorphous magnetic material whose crystallization temperature (Tx) is higher than the Curie temperature (Tc), or Co 75 atomic% to 84 atomic%, Ni 2 atomic% to 6 atomic%, Mo 5 atomic% to 10 atomic%, Contains Nb 0.5 to 5 atom%, B 0.1 atom% to 5 atom%, Zr 7 atom% to 9 atom%, satisfies Mo+Nb+Zr 13 atom% to 20 atom% and Co+Ni+Mo+Nb+B+Zr=100, and crystallization temperature ( A magnetic material whose Tx) is higher than the Curie temperature (Tc) and is preferentially amorphous is lower than the crystallization temperature (Tx) of the amorphous magnetic material.
Maintain the magnetic material in the temperature range above the Curie temperature (Tc) for 1 to 100 minutes, and then apply a magnetic field that rotates relative to the magnetic material to the magnetic material while maintaining the temperature in the Curie temperature range of 150°C to the above Curie temperature. This is a heat treatment method for magnetic materials characterized by holding the heat for 1000 minutes. In this invention, the target amorphous magnetic material is mainly composed of at least one of Zr, Ti, Hf, Nb, Ta, and Y from 5 at% to 20 at% and Co from 65 at% to 85 at%. The reason why magnetic materials are limited to those whose crystallization temperature is higher than the Curie temperature is because outside this limited range, metal-to-metal type amorphous magnetic materials with desirable characteristics as magnetic materials for magnetic heads cannot be obtained. This is because the magnetic permeability improvement mechanism of the two-stage heat treatment of the present invention described above does not work effectively. The above Co and Zr as the main amorphous element,
Various additive elements other than Ti, Hf, Nb, Ta, and Y are added to improve various properties.For example, Mo and Cr are added to improve corrosion resistance, and to reduce magnetostriction. Ni is added to
Mn and Fe are added to increase the magnetic flux density. Even if such additive elements are added, the composition is within the range of the above elements, and substantially metal-to-metal type amorphous magnetic material that contains less than about 10 atomic percent or no metalloid elements. If so, the heat treatment method according to the present invention can be applied to all of them, and the same effects can be obtained. In this invention, if the temperature is kept below the crystallization temperature and above the Curie temperature for less than 1 minute, the above effect cannot be obtained, and if kept for more than 100 minutes, the magnetic properties may deteriorate or become brittle. Therefore, the heating time needs to be 1 to 100 minutes, preferably 3 to 20 minutes, and most preferably 5 to 10 minutes. The temperature at which the magnetic material is maintained while applying a magnetic field that rotates relative to the magnetic material is 150°C or higher,
If the temperature is not within the range below the Curie temperature, there is no effect of reducing the magnetic anisotropy to substantially zero, so this temperature range is set. In addition, the above effect does not occur if the time for holding the magnetic material in a temperature range of 150°C or higher and the Curie temperature or lower while applying a magnetic field that rotates relative to the magnetic material is less than 1 minute, and 1000 minutes. If it exceeds this, the magnetic properties will deteriorate, so the duration should be 1 to 1000 minutes, but it is necessary to select the combination of holding temperature and holding time appropriately depending on the composition of the magnetic material and the required magnetic properties. Desired retention time is 5~
It is 300 minutes, more preferably 5 to 150 minutes. In addition, the strength of the rotating magnetic field applied to the magnetic material may be selected appropriately depending on the magnitude of the induced magnetic anisotropy of the magnetic material, but 1 kG or more is required, and 3 kG or more is sufficient. , preferably 5kG or more. Reasons for limiting the components In this invention, the reasons for limiting the target amorphous magnetic materials are as described above, and here,
The reason for limiting the components of the amorphous magnetic material that is most suitable for the magnetic material for the magnetic head described in claim 4 will be explained. Co is the main component in this composition,
75 atomic% to obtain a magnetic flux density of approximately 6000G or more
However, if it exceeds 84 atom%, the magnetic permeability in low measurement magnetic fields will not improve, so 75 atom%
The content is preferably 77 atomic % to 82 atomic %, more preferably 77 atomic % to 88 atomic %. Ni is added to have the effect of reducing magnetostriction and making it negative without reducing the magnetic flux density, and within the content range of other component elements, it makes the magnetostriction substantially zero or slightly negative and the magnetic flux density In order to make a magnetic material of 6000G or more, it is necessary to add more than 2 atom %, but if it exceeds 6 atom %, the crystallization temperature and saturation magnetic flux density will decrease, so the addition of 2 atom % or more is necessary.
The addition amount is 6 atomic %. Mo is an element that makes magnetostriction negative, improves magnetic permeability, and increases the thermal stability of magnetic permeability or coercive force, and is added, but if it is less than 5 at%, it will not have the above effect, and if it exceeds 10 at% , since the magnetic flux density decreases significantly, the content is set at 5 to 10 at%. Nb has the ability to form an amorphous state next to Zr and B, and Zr
It has the effect of increasing the amorphous formation ability by being contained together with Mo and B, and has the effect of making magnetostriction negative like Mo and promoting the improvement of magnetic permeability after heat treatment, so it is added at 0.5 atomic % or more. However, since the effect of improving magnetic properties cannot be obtained even if it is added in an amount exceeding 5 at%, the content is set at 0.5 at% to 5 at%,
Desirably, the range is 1.5 atomic % to 5 atomic %. When B is contained at the same time as Zr, it is effective in increasing the amorphous formation ability of the material and reducing magnetic anisotropy. Even if it is added in an amount exceeding 5 atomic percent, it is not very effective in reducing magnetic anisotropy, and the magnetic flux density decreases, making it more likely to become brittle.
Furthermore, the thermal stability of magnetism also decreases, so 0.1
The content is from atomic% to 5 atomic%. Also, preferably,
The content is preferably 0.5 atomic % to 3 atomic %, and furthermore, in order to obtain extremely high thermal stability, the content is preferably 0.5 atomic % or more and 1 atomic % or less. Zr is the main amorphous element in this system composition,
In order to easily become amorphous and obtain a stable amorphous state, it is necessary to contain 7 at% or more.
On the other hand, it is an element that makes the magnetostriction of the magnetic material positive, and in order to bring the magnetostriction as close to zero as possible, it needs to be 9 atomic % or less, and 7 atomic % to 9 atomic %.
shall be. In addition, Mo, Nb, and Zr have the effect of lowering the Curie temperature, but their total content is 13 at%
Mo + Nb
+Zr should be 13 at% to 20 at%, preferably 15
A preferable range is atomic% to 18 atomic%. This amorphous magnetic material contains the above-mentioned elements in various combinations, and satisfies Mo+Nb+Zr from 13 at.% to 20 at.% and Co+Ni+Mo+Nb+B+Zr=100. In addition, the ribbon or thin film of the amorphous magnetic material has low coercive force and magnetostriction, and has extremely high magnetic permeability, especially in low measured magnetic fields, and can provide magnetic properties that are thermally stable over time. Furthermore, it has excellent corrosion resistance and wear resistance, is less susceptible to embrittlement than conventional amorphous magnetic materials containing large amounts of metalloid elements, and has excellent machinability such as punching and cutting. In addition, the electrical resistance is high at 120 to 140μΩcm,
Furthermore, since it can be obtained in the form of a ribbon or film with a thickness of several hundred Å to 50 μm, it is ideal as a core material for a magnetic head, and is also suitable as a small magnetic core material with good real frequency characteristics. Example Figure 1 is a graph showing the relationship between the measured magnetic field and magnetic permeability in Example 2. Figure 2 shows the first-stage heat treatment temperature and second-stage heat treatment temperature in Example 4, and the temperature before and after molding. It is a graph showing the relationship between the change rate of the squareness ratio and the squareness ratio after molding. Example 1 As an amorphous magnetic alloy according to the present invention, No. 1. (at%); Co80-B5-Nb15, Tx = 495°C, Tc = 450°C No. 2. (at%); Co80-B5- Ta5-Zr10, Tx=560℃, Tc=490℃ No.3. (at%); Co70.5-Fe4.5-Si15-B10 Tx=490℃, Tc=440℃ Ultra-quenched molten metal Width: approx. 15mm, thickness: approx.
A 30 μm thin strip was produced, a 10 mmφ×6 mmφ ring was punched out, annealed for 5 minutes at a temperature approximately 45-50°C lower than each crystallization temperature, and then water-cooled to measure the dependence of magnetic permeability on the magnetic field. Each ring was then heated at 350°C in a 15kOe magnetic field.
After heat treatment in a rotating magnetic field for 30 minutes, magnetic properties were measured. The measurement results are shown in Table 1. As is clear from the results in Table 1, No. 1 and No.
The second-stage heat treatment of the amorphous magnetic material No. 2 dramatically improves the magnetic permeability in a low magnetic field. - It can be seen that significant effects can only be obtained when applied to metal-based amorphous magnetic materials. Example 2 No.4 and No.5 (at%); Co78.8―Ni3.2―Mo7―Nb2―B0.95―Zr8.05, Tx=556℃, Tc=480℃ No.6 (at% ); Co85-Ni2-Nb1-Mo1-B4-Zr7, Tx=483℃, Tc>Tx (cannot be measured because Tc is higher than Tx) A molten metal with a composition of
A 30 μm thin strip was produced, and rings of 10 mmφ×6 mmφ were punched out. After each ring was subjected to the heat treatment shown below, the magnetic permeability was measured at room temperature. Heat treatment conditions: No. 4 according to the heat treatment of the present invention was heated at 500° C. for 5 minutes, cooled with water, and then heat treated in a rotating magnetic field at 300° C. for 20 minutes. Comparative Example No. 5 was heated at 500° C. for 5 minutes and then cooled with water.
Comparative Example No. 6 was subjected to heat treatment in a rotating magnetic field at 380° C. for 30 minutes. The magnetic permeability measurement results are shown in Figure 1, and in a low measurement magnetic field of about 1 mOe, the comparative example
It can be seen that No. 6 has a permeability of 4,000 to 5,000, and Comparative Example No. 5 has a permeability of only about 10,000, but No. 4 of the present invention has a significantly high magnetic permeability of 20,000 or more. Incidentally, a C-shaped recording/playback magnetic head was made using the above magnetic material, and when it was attached to the same recorder, the playback sensitivity at 333Hz was measured.
Compared to the magnetic head using the magnetic material of Comparative Example No. 6, the magnetic head using the magnetic material of No. 4 subjected to the heat treatment of the present invention showed a value 5 dB higher, indicating that it has superior mounting characteristics. . Example 3 As an amorphous magnetic alloy according to the present invention, No. 7 (at%); Co79-Ni3-Mo7-Nb2-B0.9-Zr8.1, Tx=558℃, Tc=478℃ No.8 ( at%); Co79-Ni13-Mo9-B0.9-Zr8.1 The molten metal with the composition Tx=556℃, Tc=483℃ is ultra-quenched to a width of about 15mm and a thickness of about
After producing a 30μm thin strip and punching out a 10mmφ×6mmφ ring, and annealing each sample at 500℃×5 minutes, the magnetic properties of the obtained sample and the frequency dependence of magnetic permeability μz (measured magnetic field 10mOe) permeability (1kHz)
The level characteristics of were measured. Furthermore, the same sample was subjected to heat treatment in a rotating magnetic field of 9.8 kOe at 350°C for 20 minutes, and the same magnetic properties were measured. The results of these measurements are shown in Table 2. As is clear from Table 2, 2 according to this invention
It can be seen that the magnetic permeability is dramatically improved by the step heat treatment, and in particular, the magnetic permeability at a low measurement magnetic field is significantly improved.

【table】

[Table] Example 4 No.9 (at%); Co78―Ni4.5―Mo6.5―Mb2―B1―Zr8, Tx=550℃, Tc=490℃ A molten metal with the following composition was ultra-quenched and the width Approximately 15mm, thickness approximately
The effect of the heat treatment method according to the present invention was investigated using a sample obtained by manufacturing a 30μ thin strip and punching out a ring of 10mmφ×6mmφ. First, the heating temperature was 490℃ by heating for 5 minutes in an Ar atmosphere in a non-induction furnace and then cooling with water.
℃ and 510℃, respectively. The BH curve of the heat-treated sample was measured using a DC BH tracer, and then the sample was molded with epoxy resin and the BH curve was measured in the same manner. From these BH curves, the squareness ratio (Br/
Bs) were determined, and the rate of change in squareness ratio before and after molding was determined. Generally, a magnetic head has a core material placed in a case.
This is manufactured by molding it with resin, but it is known that even a slight change in magnetostriction (1 ppm or less) can significantly change the characteristics depending on the mold. For example, if the magnetostriction is on the positive side, compressive stress will be applied by the mold, and the squareness ratio (Br/Bs) will be small; on the other hand, if the magnetostriction is on the negative side, the squareness ratio will be large after molding. Become. As shown in the measurement results in Figure 2, □ and ○ indicate the change in the squareness ratio before and after this molding, and the value is R _{1 for the squareness ratio before molding, and R 1} for the squareness ratio after molding. R ₂ is expressed as 1-R ₂ /R _1. When this value is 0, it indicates that the squareness ratio has not changed, and when it is negative, the squareness ratio after molding has increased (magnetostriction is It can be seen that when it is positive, the squareness ratio after the mold has decreased (the magnetostriction is shifted to the positive side). In addition, ■ and ● indicate the squareness ratio after molding, and it is said that approximately 0.4 to 0.6 is practically good. As is clear from Figure 2, the rate of change in the squareness ratio due to molding also changes depending on the temperature of the first stage heat treatment, which corresponds to normal heat treatment, and the higher the heat treatment temperature, the smaller the rate of change. In other words, it can be seen that the magnetostriction is shifting from the minus side to the plus side. Next, the sample that had been subjected to the first heat treatment at 510° C. for 5 minutes was rotated in a 15 kG magnetic field and subjected to the second heat treatment. The processing temperatures were 250℃ and 250℃, respectively.
Conducted at four different temperatures: 300℃, 350℃, and 400℃.
The square shape and its change rate before and after molding were determined using the same method as above. Due to the second heat treatment, the rate of change in the squareness ratio shifted to the positive side, in other words, the magnetostriction changed from the negative side to the positive side.
In addition, the higher the second stage heat treatment temperature, the more remarkable this tendency becomes.For example, in the sample heat-treated at 400℃, the rate of change in squareness ratio increases from -0.71 to 0.86, and the squareness ratio after molding increases. The ratio has decreased from 0.66 to 0.06. In this way, even if the magnetostriction of the amorphous magnetic material in the rapidly cooled state or in the state subjected to normal heat treatment is minus several ppm, it is possible to mold the material by appropriately selecting the second heat treatment temperature as described above. It is possible to obtain a core material in which the squareness ratio between the front and back hardly changes. Example 5 As an amorphous magnetic alloy according to the present invention, No.10 (at%); Co78.7—Ni3.5—Mo6.8—Nb2—B0.9—Zr8.1, Tx=555°C, Tc= The molten metal with a composition of 485℃ is ultra-quenched to form a material with a width of approximately 15 mm and a thickness of approx.
A 30 μm thin strip was produced, a ring of 10 mmφ×6 mmφ was punched out, the sample was heated at 500°C for 5 minutes, cooled, and then heat treated in a rotating magnetic field of 15 kOe at 300°C for 20 minutes. As a comparative example, a molten metal with the composition No. 11 (at%); Co69-Fe4-Nb2-Si10-B15, Tx = 520℃, Tc = 320℃ was ultra-quenched, and a width of approximately 15 mm and a thickness of approximately
A 30 μm thin strip was produced, a ring of 10 mmφ×6 mmφ was punched out, and the sample was heated at 430° C. for 10 minutes and then cooled with water. Magnetic permeability μz of the obtained sample at 1kHz and 10mOe
(1kHz, 10mOe) was measured. Next, the sample was heated and held at 120°C, then cooled, and its magnetic permeability was measured at room temperature.The degree of deterioration of the magnetic permeability due to heating and holding at 120°C was measured, and its time dependence is shown in Table 3. Generally, when assembling and processing a magnetic head by laminating core materials processed into thin plates, it is often heated at a temperature of 80°C to 150°C for about 3 to 6 hours. It can be seen that even after the heating process, the deterioration of magnetic properties is less than that of the comparative example.

【table】 [Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between the measured magnetic field and magnetic permeability in Example 2, and Fig. 2 is a graph showing the relationship between the measured magnetic field and magnetic permeability in Example 4. It is a graph showing the relationship between the rate of change in ratio and squaring after molding.

Claims (1)

[Claims] 1 The main component is 5 at% of at least one of Zr, Ti, Hf, Nb, Ta, and Y, and 55 at% to 85 at% of Co6, and
An amorphous magnetic material whose crystallization temperature (Tx) is higher than the Curie temperature (Tc) is lower than the crystallization temperature (Tx) of the amorphous magnetic material,
Maintain the magnetic material in the temperature range above the Curie temperature (Tc) for 1 to 100 minutes, and then apply a magnetic field that rotates relative to the magnetic material to the magnetic material while maintaining the temperature in the Curie temperature range of 150°C to the above Curie temperature. A method for heat treatment of magnetic materials characterized by holding for ~1000 minutes. 2. The method for heat treating a magnetic material according to claim 1, wherein the holding time in the Curie temperature range of 150° C. to the Curie temperature of the magnetic material is 5 to 150 minutes. 3. The method of heat treating a magnetic material according to claim 1, wherein the applied magnetic field strength is 5 kOe or more. 4 Co75 atomic% - 84 atomic%, Ni2 atomic% - 6 atomic%, Mo5 atomic% - 10 atomic%, Nb 0.5 atomic% - 5 atomic%, B0.1 atomic% - 5 atomic%, Zr7 atomic% - 9 A magnetic material that contains Mo+Nb+Zr13 to 20 atom% and Co+Ni+Mo+Nb+B+Zr=100, and has a crystallization temperature (Tx) higher than the Curie temperature (Tc) and is preferentially amorphous. Below the crystallization temperature (Tx) of the amorphous magnetic material,
Maintain the magnetic material in a temperature range equal to or higher than the Curie temperature (Tc) for 1 to 100 minutes, and then apply a magnetic field that rotates relative to the magnetic material to the magnetic material in the Curie temperature range of 150°C to the above-mentioned Curie temperature. A method for heat treatment of magnetic materials characterized by holding for ~1000 minutes.