JPH06274830A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To provide the thin-film magnetic head which suppresses thermal noises generated by heat generation of an MR element and can reproduce signals at a high density. CONSTITUTION:This thin-film magnetic head has a lower magnetic film 34 consisting of 'Permalloy(R)', an insulating film 36 consisting of aluminum nitride, the MR element 38, an electric conductor 40 for supplying current to this MR element 38, an insulating film 42 consisting of aluminum nitride and an upper magnetic film 44 consisting of 'Permalloy(R)' on the upper part of a substrate 32. The heat generated by the MR element 38 is transmitted via the insulating films 36, 42 consisting of the aluminum nitride having an excellent thermal conductivity to the magnetic films 34, 44 and is released outside even if the heat is generated in the MR element 38 when an electric current is supplied from the electrical conductor 40 to the MR element 38. Consequently, the thermal noises of the MR element 38 are suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head, and more particularly to a magnetoresistive head.

[0002]

2. Description of the Related Art In a magnetic recording apparatus, a magnetoresistive head is used to meet the demand for high density recording. This is because the magnetoresistive head uses a magnetoresistive element whose electric resistance changes according to a magnetic field, and thus can reproduce a signal with higher sensitivity than an inductive magnetic head. It is necessary to connect an electric conductor to the magnetoresistive effect element in order to pass a sense current and take out a reproduced signal.

A recording / reproducing separated composite thin film magnetic head using a general magnetoresistive effect element (hereinafter referred to as MR element) is constructed as shown in FIG. That is,
A lower magnetic film 4 serving as a magnetic shield layer, an insulating film 6 made of SiO ₂ , Al ₂ O _3, etc., an MR element 8 made of a permalloy film, and the MR element 8 are energizable on a substrate 2 made of alumina titanium carbide. The electric conductor 10 which is applied with a sense current, and SiO ₂ , Al ₂ formed on the electric conductor 10.
A magnetoresistive head comprising an insulating film 12 made of O ₃ or the like, an upper magnetic film (lower magnetic pole) 14 formed also as a magnetic shield layer thereof and a lower magnetic pole of the inductive head, and the upper magnetic layer. Film (lower magnetic pole) 14,
The gap layer 16, the coil 20 formed in the interlayer insulating layer 18, the upper magnetic pole 22, and the inductive head including the insulating layer 24 are included.

[0004]

In the composite thin film magnetic head having such a structure, a sense current is applied from the electric conductor 10 to the MR element 8 in order to make the magnetoresistive head function. In this case, it is desirable to increase the current value of the sense current in order to increase the output, but the sense current is regulated for reasons such as electromigration.
It will be about 0 mA. The cross-sectional area of the MR element 8 is 5 μm × 4
Since it is about 0 nm, the current density is 5 × 10 ⁶ A /
As large as cm ² , the heat generation of the MR element 8 becomes a big problem. That is, heat generated by the MR element 8 causes thermal noise. Therefore, there is an inconvenience that signals cannot be reproduced at high density.

The present invention has been made to solve this kind of problem, and provides a thin film magnetic head capable of reproducing signals at a high density by suppressing thermal noise generated by heat generation of an MR element. The purpose is to

[0006]

In order to achieve the above object, the present invention provides a lower insulating film formed on a substrate, a magnetoresistive effect element formed on the lower insulating film, and the lower part. An electric conductor formed on an insulating film and conducting to the magnetoresistive effect element, and an upper insulating film formed on the element and the electric conductor are provided. At least one of the lower and upper insulating films is aluminum nitride. It is characterized by consisting of.

Further, it is preferable to provide a lower magnetic film formed between the substrate and the lower insulating film and an upper magnetic film formed on the upper insulating film.

Further, it is more preferable if an inductive head is provided.

[0009]

In the thin-film magnetic head according to the present invention, since at least one of the upper and lower insulating films sandwiching the electric conductor and the magnetoresistive effect element is made of aluminum nitride having high thermal conductivity, the magnetoresistive effect element and the electric resistance element Heat generated from the conductor is efficiently released to the outside through the insulating film, and thermal noise is suppressed. Further, when the upper and lower magnetic films are formed in contact with the insulating film, the resolution is improved at the time of reproducing a signal, heat is efficiently transferred from the insulating film to the magnetic film, and the magnetoresistive element is The heat can be released more efficiently. Furthermore, if an inductive head is provided, recording as well as reproduction is possible.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thin film magnetic head according to the present invention will be described in detail below with reference to the accompanying drawings with reference to preferred embodiments.

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a thin film magnetic head according to the present invention.

The thin film magnetic head 30 comprises a lower magnetic film 3 formed of permalloy having a thickness of about 3 μm, which is a magnetic shield layer, on a substrate 32 made of Mn-Zn ferrite.
4 is selectively formed, and an insulating film 36 made of aluminum nitride and having a thickness of about 0.3 μm is formed thereon. An MR made of permalloy selectively formed on the upper surface of the insulating film 36 by sputtering and ion schilling to a thickness of about 0.04 μm, a width of about 4 μm, and a length of about 10 μm.
An element 38 and an electric conductor 40 made of gold and having a thickness of about 0.2 μm and a width of about 4 μm are disposed so as to abut on the MR element 38 at one end (see FIG. 2).
An insulating film 36 and an insulating film 42 made of the same material as the lower magnetic film 34 are formed on the electric conductors 40, respectively.
An upper magnetic film (lower magnetic pole) 44 is formed, and the magnetoresistive head 30a is configured up to this point.

Above the lower magnetic pole 44, a gap layer 46 constituting the inductive head 30b, a thin film coil 50 formed in an interlayer insulating layer 48 made of a thermosetting resin, and further above the interlayer insulating layer 48. The magnetic pole 52 is formed, and the protective layer 54 is formed on the surface thereof.

In the thin film magnetic head 30 described above, reproduction is performed by the magnetoresistive head 30a and the inductive head 30 is used.
Recording is done at b. The magnetoresistive head 30
At a, a sense current of 10 mA for recording and reproduction is applied to the MR element 38 from a terminal (not shown) through the electric conductor 40. In this case, since the insulating films 36 and 42 that sandwich the MR element 38 and the electric conductor 40 from above and below are made of aluminum nitride having excellent thermal conductivity,
The heat generated in the element 38 is transferred to the lower magnetic film 34 and the upper magnetic film 44 through the insulating films 36 and 42, respectively,
Thermal noise that is radiated to the outside and is generated in the MR element 38 is suppressed. Therefore, the magnetoresistive head 30a
The signal can be reproduced at high density in.

Next, a thin film magnetic head constituted only by a magnetoresistive head will be described as a second embodiment. In this case, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, the magnetoresistive head 30a has a shape in which the members constituting the inductive head 30b are removed (however, the lower magnetic pole (upper magnetic film) 44).
Except for the above), and the protective layer 56 is formed on the uppermost part thereof. As a result, the magnetoresistive head 30a applies only the sense current to the MR element 38 through the electric conductor 40, and thus only reproduces the signal. At this time, similarly to the first embodiment, the heat generated in the MR element 38 is transmitted to the lower magnetic film 34 and the upper magnetic film 44 through the insulating films 36 and 42 made of aluminum nitride having high thermal conductivity, and the MR element 38 Three
8 suppresses generation of thermal noise.

The following experiments were conducted in order to confirm the effects of the first and second embodiments. As the thin film magnetic head, the magnetoresistive head 30c (see FIG. 3) in which the upper magnetic film 44 and the protective layer 56 were not formed was used. As a comparative example, the same type of magnetoresistive head having insulating films 36 and 42 made of alumina (Al ₂ O ₃ ) was used. The experiment was conducted with a sense current of 10 mA.

[0018]

[Table 1]

As shown in Table 1, the magnetoresistive head 30c of the present invention using aluminum nitride (Al N) having a high thermal conductivity is a comparative example using alumina (Al ₂ O ₃ ). It was confirmed that the thermal noise was reduced by 3 to 5 dB.

Thus, the magnetoresistive head 30c
In the above, by forming the insulating films 36 and 42 sandwiching the MR element 38 and the electric conductor 40 from aluminum nitride having excellent thermal conductivity, the heat generated from the MR element 38 is efficiently released to the outside, and thermal noise is reduced. Suppress. As a result, the signal can be reproduced with higher resolution.

[0021]

According to the thin film magnetic head of the present invention,
The following effects can be obtained.

That is, since at least one of the upper and lower insulating films sandwiching the electric conductor and the magnetoresistive effect element is formed of aluminum nitride having a high thermal conductivity, the heat generated from the magnetoresistive effect element and the electric conductor is Thermal noise can be suppressed efficiently by letting it escape to the outside through the insulating film. Therefore, signals can be reproduced with high density.

Further, if the upper and lower magnetic films are formed in contact with the insulating film, the resolution in signal reproduction is improved, and heat is efficiently transferred from the insulating film to the magnetic film, so that the efficiency is further improved. The heat can be radiated from the magnetoresistive effect element.

Furthermore, if an inductive head is provided, not only reproduction but recording can be performed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a thin film magnetic head of a first embodiment according to the invention.

FIG. 2 is a schematic plan view for explaining a connection state between an MR element and an electric conductor in the thin film magnetic head of the first embodiment according to the present invention.

FIG. 3 is a longitudinal sectional view of an essential part of a thin film magnetic head according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a thin film magnetic head according to a conventional example.

[Explanation of symbols]

 4, 14, 34, 44 ... Magnetic film 6, 12, 36, 42 ... Insulating film 8, 38 ... MR element 30 ... Thin film magnetic head 30a, 30c ... Magnetoresistive head 30b ... Inductive head

Claims (3)

[Claims] 1. A lower insulating film formed on a substrate, a magnetoresistive effect element formed on the lower insulating film, and an electric conductor formed on the lower insulating film and energized to the magnetoresistive effect element. And an upper insulating film formed on the element and the electric conductor, wherein at least one of the lower and upper insulating films is made of aluminum nitride. 2. The thin film magnetic head according to claim 1, further comprising a lower magnetic film formed between the substrate and the lower insulating film, and an upper magnetic film formed on the upper insulating film. And thin film magnetic head. 3. The thin film magnetic head according to claim 1, further comprising an inductive head.