JPH04333203A - Soft magnetic alloy film - Google Patents

Abstract

PURPOSE:To provide a magnetically soft alloy film having excellent soft magnetic characteristics and thermal stability. CONSTITUTION:The alloy of the title alloy film has the composition of FeaMcBdCe or (Fe1-bTb)aMcBdCe, where M indicates the elements of Zr and the like, and T indicates the elements of Co, Ni and the like, and 70<=a<=90, b<=0.05, 5<=c<=15, 0.5<=d<=15, 0.5<=e<=15, 1<=d+e<=20 (atomic %).The soft magnetic alloy film obtained as above has both excellent soft magnetic characteristics and thermal stability, and it is suitable for a magnetic head.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic alloy film used in magnetic heads and the like, and particularly to a Fe-based soft magnetic alloy film having excellent thermal stability, high saturation magnetic flux density, and high magnetic permeability.

0002

2. Description of the Related Art The following characteristics are generally required for soft magnetic thin films for magnetic heads. 1. High saturation magnetic flux density (hereinafter referred to as Bs). 2. High magnetic permeability (μ). 3. Low coercive force (Hc). 4. The magnetostriction constant (λs) is small. Furthermore, some magnetic heads require glass welding to form gaps, etc., and are required to have the following characteristics that can withstand high temperatures during the glass welding process. 5. Soft magnetic properties should be thermally stable.

[0003] Therefore, when manufacturing soft magnetic alloy films, magnetic heads, etc., research has been conventionally conducted from the above viewpoints. Conventional soft magnetic thin films include soft magnetic materials such as sendust and permalloy, and more recently Co-based or Fe-based materials.
Base amorphous alloys are also being used.

0004

However, as recording density increases, soft magnetic thin film materials used in magnetic heads are required to have a high saturation magnetic flux density. Also,
Some products require glass welding to form gaps, etc., and thermal stability that can withstand high temperatures during the glass welding process is also required.

[0005] However, although Sendust has excellent soft magnetic properties, it has the drawback of having a low Bs of about 11 kG. Permalloy also has a low Bs of 10 kG, and has the disadvantage that its soft magnetic properties deteriorate when subjected to high-temperature treatment in glass welding processes, etc., and that its magnetic permeability in high frequency bands is low due to its low electrical resistance.

Furthermore, Fe-based or Co-based amorphous alloys can be welded with low melting point glass if the Bs is kept below 9 kG, but welding at temperatures above 600 degrees is difficult, and they have excellent environmental resistance. medium to high melting point glasses cannot be used.

[0007] In order to overcome the above-mentioned drawbacks, an object of the present invention is to provide a film with soft magnetic properties equivalent to or better than conventional soft magnetic alloy films, and particularly with good saturation magnetic flux density and thermal stability. An object of the present invention is to provide a soft magnetic alloy film having the following properties.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the invention as set forth in claim 1 provides a soft magnetic alloy film having a composition represented by the following formula. Fea Mc Bd Ce However, M is one or two of Zr, Nb, Hf, Ta
It is an element more than a species, 70≦a≦90, 5≦c≦15, 0.5≦d≦15, 0
．． 5≦e≦15, 1≦d+e≦20 (atomic %).

[0009] In order to solve the above-mentioned problem, the invention as set forth in claim 2 provides a soft magnetic alloy film having a composition represented by the following formula. (Fe1-b Tb) a Mc Bd Ce However, T is at least one or two elements among Co and Ni, and M is at least one or two or more elements among Zr, Nb, Hf, and Ta. and 70≦a≦90, b
≦0.05, 5≦c≦15, 0.5≦d≦15, 0.5
≦d≦15, 0.5≦e≦15, 1≦d+e≦20 (atomic %).

[0010] In order to solve the above problem, the invention according to claim 3 heat-treats the soft magnetic alloy film according to claim 1 or 2, so that the metal structure thereof substantially has an average grain size of 0.08 μm.
It consists of the following crystal grains.

[0011] In order to solve the above-mentioned problem, the invention according to claim 4 heat-treats the soft magnetic alloy film according to claim 1 or 2, so that the metal structure thereof substantially has crystal grains with an average grain size of 0.08 μm or less. and an amorphous phase.

The present invention will be explained in more detail below.

The soft magnetic alloy film of the present invention is produced by a process of obtaining an amorphous alloy having the above composition or a crystalline alloy containing an amorphous phase by a vapor phase quenching method such as a sputtering method or a vapor deposition method, and a process of obtaining an amorphous alloy having the above composition or a crystalline alloy containing an amorphous phase. It is obtained through a heat treatment step in which the alloy obtained in step 1 is subjected to heat treatment to precipitate fine crystal grains. The reason why the alloy is heat treated here is that the as-deposited alloy produced by the vapor phase quenching method contains a considerable amount of amorphous phase, has a low Bs, and has insufficient soft magnetic properties. As the sputtering apparatus, existing ones such as RF two-pole sputtering, magnetron sputtering, three-pole sputtering, ion beam sputtering, and facing target sputtering can be used.

[0014] The reason for limiting the components as described above and the reason for their addition will be described below.

[0015] Fe is the main component and is an element responsible for magnetism. Therefore, in order to obtain soft magnetic properties, the Bs content must be 90 atomic % or less, and in order to obtain Bs of 10 kG or more, the Bs content must be 70 atomic % or more.

Element T (=Co, Ni) is an element added by replacing Fe in order to adjust magnetostriction. As will be described later, in a film without addition of T, the magnetostriction constant becomes a negative value when the heat treatment temperature is high or when the total amount of B and C is relatively small. In this case, the magnetostriction constant can be made positive by adding T, and by adjusting the amount added, 10
It can be set to a value in the range of -5 to 10-7. Further, since T is also an element responsible for magnetism, the decrease in Bs can be suppressed to a low level. However, if too much is added, the magnetostriction becomes too positive and it becomes difficult to obtain soft magnetic properties, so the content needs to be 5 at % or less. However, when the heat treatment temperature is relatively low or when the total amount of B and C is relatively large, it is not necessary to add T.

Element M (=Zr, Nb, Hf, Ta) is used to improve the soft magnetic properties and to make it easier to obtain an amorphous phase in the state created by the vapor phase quenching method (before heat treatment). 5 atomic % or more1 to maintain soft magnetic properties.
It is necessary to keep it below 5 atomic %. If 15 at % or more is added, an amorphous phase can be obtained, but good soft magnetic properties cannot be obtained even after heat treatment.

[0018] In order to improve the soft magnetic properties, boron B has the effect of making it easier to obtain an amorphous phase, the effect of suppressing the formation of a compound phase that adversely affects the soft magnetic properties when subjected to heat treatment, and b. mainly composed of Fe; c. It is thought that this has the effect of suppressing the grain growth of the c-phase. In order to obtain good soft magnetic properties, the content needs to be 0.5 atomic % or more and 15 atomic % or less.

Carbon C is used to improve soft magnetic properties.
In addition to the effect of making it easier to obtain an amorphous phase, b. c. This has the effect of making the precipitation of the c phase uniform. In order to obtain good soft magnetic properties, it is necessary to keep the content between 0.5 atomic % and 15 atomic %.

[0020]

[Example 1] The thin films of the following examples were prepared by depositing Co, Ni, Zr, and Nb on Fe targets using an RF two-pole sputtering system.
, Hf, Ta, B, and C (graphite) pellets were appropriately selected and arranged on a composite target using Ar gas to form a film with a thickness of 5 to 6 μm. A 4 mm x 24 mm crystallized glass substrate was used as the substrate.

Each of the obtained alloy films was subjected to various heat treatments, and the influence of the composition of the alloy film on μ, Hc, λs, and Bs was investigated. All heat treatments were performed in a non-magnetic field, with heating up to the set temperature taking 40 minutes and cooling from the set temperature to room temperature taking 1.5 minutes.
It was performed at °C/min. Further, the film structure at that time was investigated using an X-ray diffraction apparatus using Co-Kα rays.

Magnetic permeability was measured using a figure 8 coil, coercive force was measured using a DC B-H loop tracer, saturation magnetic flux density was measured using VSM, and magnetostriction constant was measured using an optical lever method. Table 1 shows the results of the soft magnetic alloy film prepared and measured as described above.
They are shown in Tables 3 to 3 and FIGS. 1 to 4.

[0023]

[Table 1]

Table 1 shows that in Fe-Ta-B-C, 55
The relationship between the magnetic permeability μ, coercive force Hc, magnetostriction constant λs, saturation magnetic flux density Bs, and film composition at 1 MHz after heat treatment at 0° C. and 650° C. is shown. It is clear from Table 1 that
The soft magnetic thin film in the present invention is particularly suitable for sample No. 3 shows μ (1 MHz) of 3000 or more, Hc of 0.1 Oe or less, λs of 10 −6 to 10 −7 range, and Bs of 15 kG or more. In addition, in the case of a video head,
It is sufficient that μ is at least 1000 (1 MHz), and it can be seen that the soft magnetic thin film of the present invention has extremely excellent soft magnetic properties.

FIG. 1 shows sample No. 1 in Table 1. 1 Fe8
This is an X-ray diffraction pattern of a 0.8Ta7.0 B7.5 C4.7 film. In the pattern immediately after sputtering, b. c.
．． Reflections from the {110} and {220} planes of c-Fe appear. The crystal grain size determined from Sherrer's equation is approximately 8 nm, with fine b. c. It can be seen that it shows the c phase. In addition, sample No. 1 includes b. c. No crystal phases other than c-phase were precipitated.

FIG. 2 shows sample No. 1 in Table 1. 1 (black circle) and No. It is a graph showing the relationship between μ (1 MHz) of No. 3 (white circles) and heat treatment temperature. It is clear from FIG. 2 that sample No. Sample No. 1 exhibits a magnetic permeability μ of 2000 or more in the temperature range of 500° C. to 650° C. 3: μ is 1000 or more in the range from room temperature to 450℃, 550℃
μ shows a value of 2000 or more in the temperature range from 650°C to 650°C.

FIG. 3 shows sample No. 1 in Table 1. 1 (black circle) and No. 3 (white circles) is a graph showing the relationship between magnetostriction λs and heat treatment temperature. From FIG. 3, sample No. It can be seen that when both Nos. 1 and 3 are subjected to heat treatment at 600° C. or higher, λs shows a small value of 10 −7 range.

FIG. 4 shows sample No. 1 in Table 1. 1 shows the relationship between Bs of No. 1 and heat treatment temperature. The value in the amorphous state immediately after sputtering is 7 kG, but after heat treatment at 550° C. or higher, b. c. 15.6 by precipitating the c phase
It can be seen that it shows the value of kG. This is F in the amorphous state.
Although the moment of e was reduced by Ta, B, and C, b. c. It is thought that by precipitating the c phase, the decrease in moment due to Ta, B, and C was reduced, and Bs increased.

[0029]

[Table 2]

Table 2 shows Fe-Ta-
This figure shows the relationship between μ, Hc, λs, and Bs at 1 MHz and film composition when Ta in B-C is completely replaced with Zr, Hf, and Nb. Similar to Table 1, high saturation magnetic flux density (Bs
), high magnetic permeability (μ), and low magnetostriction constant (λs).

[0031]

[Table 3]

Table 3 shows a similar relationship when Co and Ni are added to Fe-Ta-B-C. It can be seen that the addition of Co or Ni has the effect of shifting λs positively. The soft magnetic properties are also good, and the decrease in Bs is suppressed to a low level. In addition, in high-temperature heat treatment, λs becomes negative, but
By adding a small amount of Co or Ni, it is possible to shift λs positively and make it almost zero.

In this example, all heat treatments were performed in a non-magnetic field, but macroscopic differences could be obtained by performing heat treatment in a static magnetic field and using the hard-to-magnetize axis as a magnetic path, or by performing heat treatment in a rotating magnetic field. It is also possible to further improve the soft magnetic properties by suppressing directional dispersion.

[0034]

[Table 4]

Table 4 is a comparative example with the present invention, and is a sample of a portion exceeding the composition range of the present invention. In the table, Hc
, λs are not available because the sample was not saturated with the applied magnetic field of ±100 Oe and could not be measured. Also, B
s was also unmeasurable in these samples. As is clear from Table 4, when the composition range of the present invention is exceeded, μ (1 MHz)
is less than 10, making it unsuitable as a core material for a magnetic head.

[0036]

[Effect] As explained above, the present invention has magnetic permeability and coercive force equal to or greater than conventional soft magnetic alloy films, and has a saturation magnetic flux density superior to conventional soft magnetic alloy films. Furthermore, a soft magnetic alloy film having a magnetostriction constant of ±10 −6 to 10 −7 can be provided. Furthermore, since it is heat treated at high temperatures, it also has excellent thermal stability.

Therefore, the soft magnetic alloy film according to the present invention is suitable for magnetic heads and the like, and can also be applied to magnetic heads that require high temperature processing such as glass welding processes. Also, by adding B and C in combination, b. c. The c-phase precipitates into a uniform fine crystal grain structure, and the adverse effect of magnetocrystalline anisotropy on soft magnetism is reduced, resulting in good soft magnetic properties. Furthermore, the above effect can be further enhanced by adding a small amount of element T (=Co, Ni) and adjusting the magnetostriction constant.

[Brief explanation of drawings]

FIG. 1 is a graph showing an X-ray diffraction pattern of an example of a soft magnetic alloy film of the present invention.

FIG. 2 is a graph showing the relationship between the magnetic permeability μ and the heat treatment temperature of an example of the soft magnetic alloy film of the present invention.

FIG. 3 is a graph showing the relationship between the magnetostriction constant λs and the heat treatment temperature of an example of the soft magnetic alloy film of the present invention.

FIG. 4: Saturation magnetic flux density Bs of an example of the soft magnetic alloy film of the present invention
It is a graph showing the relationship between heat treatment temperature and heat treatment temperature.

Claims (4)

[Claims] 1. A soft magnetic alloy film characterized by having a composition represented by the following formula. Fea Mc Bd Ce However, M is one or more elements among Zr, Nb, Hf, and Ta, and 70≦a≦90, 5≦c≦15, 0.5≦d≦15, 0
．． 5≦e≦15, 1≦d+e≦20 (atomic %). 2. A soft magnetic alloy film having a composition represented by the following formula. (Fe1-b Tb) a Mc Bd Ce However, T is at least one or two elements among Co and Ni, and M is at least one or two or more elements among Zr, Nb, Hf, and Ta. and 70≦a≦90, b
≦0.05, 5≦c≦15, 0.5≦d≦15, 0.5
≦d≦15, 0.5≦e≦15, 1≦d+e≦20 (atomic %). 3. The soft magnetic alloy film is subjected to heat treatment,
3. The soft magnetic alloy film according to claim 1, wherein the metal structure substantially consists of crystal grains having an average grain size of 0.08 μm or less. 4. The soft magnetic alloy film is subjected to heat treatment,
3. The soft magnetic alloy film according to claim 1, wherein the metal structure substantially consists of crystal grains with an average grain size of 0.08 μm or less and an amorphous phase.