JPH05234751A - Soft magnetic alloy film and magnetic head having high saturation magnetic flux density for thin film magnetic head - Google Patents

Abstract

PURPOSE:To realize a magnetic film having high saturation magnetic flux density for a thin film magnetic head and soft magnetic characteristics by adding Ti to an Fe-N film. CONSTITUTION:A composite target wherein a Ti chip is arranged to 99.99% Fe is used and a nitride film is formed on a crystallized glass substrate by a reactive sputter device which forms a film in Ar+N2 atmosphere. Thermal treatment is carried out at an object temperature in vacuum. Atomic specific composition of an acquired alloy film is 0.5<=X<=3.0 and 2.0<=Y<=10.0 in a formula Fe100-(X+Y)TiXNY. Thereby, it is possible to acquire an optimum magnetic material by using a soft magnetic thin film of a lower core and an upper core of a thin film magnetic head for high density magnetic memory.

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 for a thin film magnetic head used for high density magnetic recording such as a computer storage device and a VTR, and a thin film magnetic head provided with the soft magnetic alloy film. Is.

[0002]

2. Description of the Related Art Conventionally, computer storage devices and VTRs
As a thin film magnetic head used in a high-density magnetic recording / reproducing apparatus such as the above, for example, a magnetic head having a structure shown in FIG. 1 is known.

FIG. 1 is a view showing a cross section of a thin film magnetic head, 1 is a non-magnetic substrate or a magnetic substrate, 2 is a lower core, 3
Is a magnetic gap, 4 is an upper core, 5 is a coil, and 6 is SiO _2.
Etc. is an insulating film.

The present invention is a novel proposal of a soft magnetic material as the lower core 2 and the upper core 4 used in the above-mentioned thin film magnetic head.

In the conventional thin film magnetic head, the soft magnetic thin films used for the lower core 2 and the upper core 4 are:
Permalloy (Fe-Ni alloy) or amorphous alloy such as Co-Nb-Zr (-Ta) is used. The main reason is a problem relating to the heat resistance of the insulating film 6 in the thin film magnetic head. The insulating film 6 is described as an insulating film such as SiO ₂ but this is only an example. In addition, a polyimide resin or a photoresist used for photoetching may be used.

Here, the heat resistant temperature of the polyimide resin is
Generally, the temperature is 400 ° C or lower, and the heat resistant temperature of the photoresist is 250 ° C or lower. Therefore, when using a polyimide resin as the material used for the insulating film 6, the manufacturing process of the thin-film magnetic head must be at least 400 ° C. or lower, and similarly when a photoresist is used. Must be below 250 ° C.

Even when a material having heat resistance such as SiO ₂ is used for the insulating film 6, it is necessary to perform the heat treatment process at about 400 ° C. at least to maintain the performance of the conductive coil 5. is there.

As described above, it is necessary to keep the heat treatment temperature at 400 ° C. or lower in the heat treatment process (eg, glass bonding or heat treatment for obtaining the characteristics of the magnetic film) in the manufacturing process of the thin film magnetic head. , It greatly affects performance or yield.

For the above-mentioned reasons, the magnetic film must show good soft magnetic properties in the state after film formation, or must exhibit good soft magnetic properties by heat treatment at 400 ° C. or lower. If you do not add it, you will not be able to use the one that does not show the characteristics.

The above-mentioned permalloy thin film and amorphous thin film are often used because they satisfy these conditions.

On the other hand, in magnetic recording, higher density has been developed, and along with this, high coercive force of magnetic disks and magnetic tapes as recording media has been attempted. In order to cope with this, the thin film magnetic head is required to have a strong recording ability to magnetize a recording medium having a high coercive force in terms of characteristics, and an overwrite such as an HDD. The system is required to have excellent overwrite characteristics.

In order to improve such characteristics, the upper core,
Increasing the saturation magnetic flux density of the magnetic film used for the lower core is an effective means.

However, the saturation magnetic flux density of the above-mentioned permalloy and amorphous alloy film is 0.8 to 1.0 (T), which is insufficient.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional example, and has a high saturation magnetic flux density for a thin film magnetic head and has a temperature of about 400 ° C. or less after film formation. The object is to provide a magnetic film having sufficient soft magnetic properties by heat treatment.

[0015]

[Means for Solving the Problems] The Fe film alone has a large saturation magnetic flux density of 2.15 (T), but is insufficient in terms of soft magnetism. On the other hand, the Fe-N film obtained by nitriding the Fe film is
It is often reported that it has excellent soft magnetic properties as compared with a film. For example, 3rd pB-8 “Nitrogen-added soft magnetic Fe”
See Structure and Magnetic Properties of Sputtered Film.

The inventor of the present invention also prepared a Fe—N film by reactive sputtering by changing the atmosphere during sputtering film formation to Ar + N ₂ and evaluated its soft magnetic characteristics. Although it exhibits excellent soft magnetic properties, the minimum coercive force of 2 to 4 oersted and 2 oersted was 7 oersted immediately after film formation.

In this case, not only is the soft magnetic property insufficient, but the soft magnetic property which is one of the gist of the present invention is stable up to about 400 ° C. immediately after the film formation.

Therefore, in the present invention, Fe-N is used as a soft magnetic alloy film having a high saturation magnetic flux density for a thin film magnetic head.
The feature is that Ti is added to the film, and specifically, the following atomic ratio composition is featured.

[0019]

[Equation 5]

At

[0021]

[Equation 6]

It is assumed that

[0023]

The magnetic alloy film satisfying the above composition exhibits a substantially flat soft magnetic property from the state immediately after the film formation to about 400 ° C., and its saturation magnetic flux density has a large value of 1.9 to 2.0 (T). Therefore, it is effective as a magnetic alloy film for a thin film magnetic head.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples.

A sputtering method is used to form the magnetic alloy film,
A film thickness of 1 μm was formed on a non-magnetic substrate.

For the target, 4 inches ¢ x 3 mm ^t 99.99
% Fe with a 5 mm square × 1 mm ^t Ti chip placed on it.
A nitride film was formed on the crystallized glass substrate at a substrate temperature of 150 ° C. using a reactive sputtering apparatus for forming a film in an Ar + N ₂ atmosphere. The heat treatment was performed in vacuum (1 × 10 −5 Torr or less) for about 1 hour at the target temperature.

The coercive force (hereinafter referred to as Hc) and the saturation magnetic flux density (hereinafter referred to as Bs) were measured by VSM.

FIG. 2 is a diagram showing the heat treatment temperature dependence of Hc of an Fe film prepared in an Ar to 100% atmosphere. The Fe film shows Hc = 15 Oersted immediately after film formation and after heat treatment at 450 ° C. At Hc = 8 oersted, this characteristic is maintained after heat treatment.

As described above, although the Fe film has Bs = 2.15 (T), it is understood that the soft magnetic property is insufficient.

FIG. 3 (a) shows the heat treatment temperature dependency of Hc in the case where the flow rate of nitrogen is 2.4% and 4.8% when the Fe film is formed in the Ar + N ₂ atmosphere, and FIG. 3 (b) is The heat treatment temperature dependency of Hc is shown when the nitrogen flow rate is 6.0% and 10.0% when the Fe film is formed in an Ar + N ₂ atmosphere.

The nitrogen flow rate ratio is represented by [N ₂ flow rate / (N ₂ flow rate + Ar flow rate (40 sccm constant))] × 100 (%).

As can be seen by comparing with FIG.
It can be seen that at 450 ° C, Hc is smaller than that of the Fe film. However, the best Hc is a nitrogen flow rate ratio of 6.
Although it was 0% and after heat treatment at 350 ° C., it was still 2 Oersted and did not show flat soft magnetic characteristics in the range from immediately after film formation to about 400 ° C., which is one of the objects of the present invention. It turns out that is intense.

FIG. 4 (a) contains the film composition of the present invention (Fe
_99-X Ti _1.0 N _X (at%)) composition of the magnetic film nitrogen flow rate ratio of 1.5% and
The heat treatment temperature dependency of Hc in the case of 3.0% is shown, and FIG. 4 (b) includes the film composition of the present invention (Fe _99-X Ti _1.0 N _X (at
FIG. 3 is a diagram showing the heat treatment temperature dependency of Hc in the case where the nitrogen flow rate ratios of the magnetic film having the composition (%)) are 6.0% and 10.0%.

FIG. 5 shows (Fe ₉₄ Ti _1.0 N ₅ (at
(%)) Composition magnetic film (nitrogen flow rate ratio = 3.0%).

As can be seen from FIG. 4, by adding 1.0 (at%) of Ti, Hc was greatly improved at a nitrogen flow rate ratio of 1.5 to 6 (%), and the characteristics were substantially flat immediately after film formation at 450 ° C. To maintain. In particular, at a nitrogen flow rate ratio of 3.0 (%), it has excellent soft magnetic properties such as Hc <1 Oersted.

Nitrogen flow rate ratio 1.5 to 6.0 (%) showing the above characteristics
The amount of nitrogen in the magnetic film of No. 2 was 2 to 10 (at%).

Next, as shown in FIG. 5, Bs has a tendency to gradually increase with heat treatment, but it is about 1.95 (T) immediately after the film formation, which is 0.8 to 1.0 (T) of permalloy or amorphous alloy thin film. It turns out that it has a large value.

FIG. 6 shows the dependency of Hc on the Ti composition in the film. However, the nitrogen flow rate ratio is 6%, which is the value after the heat treatment at 350 ° C.

From this, it can be seen that the Ti composition in the film exhibits better soft magnetic characteristics in the range of 0.5 to 3.0 (at%) than the film in which Ti is not added. Furthermore, this figure shows the best conditions for the Fe-N film (Hc after heat treatment at 350 ° C with a nitrogen flow rate ratio of 6% shown in Fig. 3).
I took it. 4), it is a big difference that the Ti-added film has flat characteristics in the range of 450 ° C. immediately after the film formation, as described in FIG.

From the above, the magnetic alloy film of the present invention has a high saturation magnetic flux density [Bs = 1.9 to 2 (T)] and immediately after film formation.
Since it exhibits excellent soft magnetic characteristics in the range of 450 ° C, it is effective as a magnetic film for a thin film magnetic head.

[0041]

The atomic composition according to the present invention, that is, a part of the Fe-N film is replaced with Ti, the Ti composition in the film is in the range of 0.5 to 3.0 (at%), and the nitrogen content in the film is 2%. By selecting ~ 10 (at%), it is possible to form a soft magnetic film with high saturation magnetic flux density.
An optimum magnetic material can be provided by using the soft magnetic thin films of the lower core and the upper core of a thin film magnetic head for high density magnetic recording. In particular, since it is an effective material for a recording medium having a high Hc, a thin film magnetic head suitable for high density magnetic recording can be provided, which is extremely useful.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a thin film magnetic head.

FIG. 2 is a diagram showing the heat treatment temperature dependence of Hc of an Fe film.

FIG. 3 is a diagram showing the heat treatment temperature dependency of Hc when the nitrogen flow rate ratios of the Fe—N film are different.

FIG. 4 is a diagram showing the heat treatment temperature dependency of Hc when the Fe _99-X Ti _1.0 N _X (at%) films containing the film composition of the present invention have different nitrogen flow rate ratios.

FIG. 5 is a diagram showing the heat treatment temperature dependence of Bs of the magnetic film of the present invention.

FIG. 6 is a diagram showing the composition amount dependency of Ti in the Hc film of the present invention. 1 non-magnetic or magnetic substrate 2 lower core 3 magnetic gap 4 upper core 5 coil 6 insulating film

Claims (2)

[Claims] 1. A soft magnetic alloy film having a high saturation magnetic flux density for a thin film magnetic head, which has the following atomic ratio composition. [Equation 1] In the above equation, 2. A thin-film magnetic head comprising a soft magnetic alloy film having the following atomic ratio composition near the gap. [Equation 3] In the above equation,