JP3030606U - Composite metal wire and magnetic head using the same - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a wire rod having a diameter of 15 µm or less and having a tensile strength of 20 g or more in order to enable winding work. Further, by using this wire, a composite type magnetic head capable of supporting a recording density of 600 Mb / in ² or more is provided. A wire having a diameter of 11 μm or less and a tensile strength of 20 g or more, for example, an inner layer having a circular cross-section formed of tungsten and a specific resistance of 6 ×
A composite metal wire is made of a material of 10 ⁻⁸ Ω · m or less, for example, an outer layer having a cylindrical cross-section formed by electrolytic plating of copper. The diameter of this composite metal wire is 15 μm or less, and its electrical resistance is 300 Ω / m or less. Further, this composite metal wire is used for a coil of a composite type magnetic head.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a composite type magnetic head winding, particularly a high density magnetic recording head winding, and a magnetic head using the same.

[0002]

[Prior art]

With the spread of computers, the capacity and speed of magnetic recording devices are rapidly increasing. Along with this, the magnetic head has been required to have a smaller size and a lower inductance. Therefore, in order to increase the effective recording area and improve the running followability with the increase in capacity and speed of the magnetic recording device, the standard slider size of 4.3 mm × 2. A slider having a size of 2.0 mm × 1.6 mm × 0.46 mm, which is called a “50% slider”, is mainly used for 9 mm × 0.86 mm. Further, a slider having a size called "30% slider" is being considered. In addition, in order to improve the transfer rate, it is necessary to increase the frequency during recording and reproduction. Therefore, it is necessary to reduce the inductance of the magnetic head so that the rise time of the recording current in the high frequency region can be shortened. For example, in the case of 600 Mb / in ² , the inductance is 0.9 μH or less, and in the case of 700 Mb / in ² , the inductance is 0.7 μH or less. In order to reduce the inductance of the magnetic head, it is necessary to reduce the cross-sectional area of the magnetic path, for example, to reduce the thickness of the magnetic core, but this reduces the efficiency of the head. Become. To improve this, the magnetic path length is shortened. By reducing the winding window, the inductance can be further reduced.

However, the winding window of the magnetic core needs to wind at least a predetermined number of turns in order to obtain the minimum output characteristics. For example, in the case of 600 Mb / in ² , it is 26 times, and 700 Mb / in ² In this case, it is considered necessary to make the winding 24 times or more, and it is necessary to secure a size that allows the winding. Therefore, the minimum size of the winding window depends on the diameter of the wire used for winding. The wire material used conventionally is copper, its minimum diameter is 22 μm, and its tensile strength is 20 g. It is technically possible to further reduce the thickness of the copper wire, which is a conventionally used wire material. However, since the winding work is actually performed manually by a person, if the tensile strength of the wire is low, there is a problem such as disconnection during the work, and the tensile strength of the wire must be at least 20 g. Therefore, it is difficult for mass production to use a further thinned copper wire as a wire material for winding. Therefore, it is difficult to achieve a recording density of 600 Mb / in ² or more with a magnetic head using a wire material such as a conventional copper wire.

As the structure of the composite type magnetic head, a core chip embedded type is known. In order to manufacture this magnetic head, first, track processing is performed, and a core chip having a thickness (d) of 50 μm is inserted into the core chip insertion groove of the slider and temporarily fixed. Then, in order to fix the core chip to the slider, glass is melted and poured around the track portion. After that, remove the temporary fixing material from the back part and pour the resin into that part to fix it. After that, the excess glass on the sliding surface is removed and polishing is performed so as to obtain a predetermined gap depth. Coil winding is applied to the slider thus formed.

[0005]

[Problems to be solved by the device]

An object of the present invention is to provide a wire having a diameter of 18 μm or less including an insulating coating and having a tensile strength of 20 g or more to enable winding work. Another object of the present invention is to provide a composite type magnetic head using the above wire material, which can cope with a recording density of 600 Mb / in ² or more.

[0006]

[Means for Solving the Problems]

The present invention has been made to solve the above-mentioned problems, and a composite metal wire according to the first invention is an insulating layer provided on an inner layer having a substantially circular cross section, an outer layer of metal having a cylindrical cross section, and an outer layer. The gist of the present invention is that the diameter of the composite metal wire made of a coating and including an insulating coating is 18 μm or less and the electrical resistance thereof is 300 Ω / m or less. Further, it is more preferable that the diameter of the composite metal wire including the insulating coating is 15 μm or less. Further, it is preferable that the inner layer is made of a wire material having a diameter of 12 μm or less and a tensile strength of 15 g or more. Further, the inner layer can be made of any of metallic, carbonaceous and organic materials. Furthermore, it is preferable that the outer layer is made of a material having a specific resistance of 6 × 10 ⁻⁸ Ω · m or less. The tensile strength of the composite wire having an insulating coating on the outer side of the outer layer is preferably 20 g or more.

The composite magnetic head of the second invention has a substantially circular cross-sectional shape in which the diameter of the composite metal wire including the insulating coating is 18 μm or less and the electric resistance thereof is 300 Ω / m or less. The gist of the present invention is to use as a winding wire a composite metal wire comprising an inner layer and an outer layer of a metal having a cylindrical cross-sectional shape.

Here, the recording density means the product of the track density and the linear recording density.

[0009]

[Embodiment of device]

 The composite metal wire of the present invention comprises an inner layer (1) having a circular cross section and an outer layer (3) of metal having a cylindrical cross section as shown in FIG.

As the material of the inner layer (1), there are metal fibers such as tungsten, molybdenum, beryllium copper, brass and platinum, which are fine lineable materials. Tungsten is preferred in terms of strength. A wire having a diameter of the inner layer (1) of 12 μm or less and a tensile strength of 15 g or more is preferable. As the material of the inner layer (1), carbon fiber, SiC fiber, or organic fiber, which is a material that can be thinned, can be applied. Examples of the material of the organic fibers include phenol, nylon 6, nylon 66, polyamide synthetic fibers represented by Kepler, polyester synthetic fibers represented by polyethylene terephthalate, and vinyl chloride.

When the diameter of the metal fiber such as tungsten or molybdenum which is difficult to be plastically processed is larger than a predetermined value, the diameter is set to a predetermined value by electrolytic polishing or the like.

Further, as the material of the outer layer (3), there are metals such as Ag, Cu and Au which have a specific resistance of 6 × 10 ⁻⁸ Ω · m or less.

The material of the outer layer (3) is formed by electrolytic plating when the material of the inner layer (1) is conductive, and electroless plating when the material of the inner layer (1) is non-conductive. The thickness of the outer layer (3) is such that the electric resistance is 300 Ω / m or less. Note that a vacuum evaporation method, a sputtering method, or the like may be used. The formation of the outer layer (3) may be performed under generally known ordinary conditions.

The composite type magnetic head according to the second aspect of the present invention uses the composite metal wire according to the first aspect of the present invention. As the magnetic core, Mn-Zn ferrite grown by the solid layer reaction method was used. For the metal between the gaps, a Fe-Ta-N film having a thickness of 2 μm and a thickness of 5 μm was formed by a sputtering method. The composite metal wire produced in Example 1 was used as the coil of the magnetic head. A 700 Mb / in ² 50% slider core shown in FIG. 2, that is, a core thickness of 35 μm, and a winding window size of 0.10 mm × 0.20 mm could be wound 26 times without breaking. Its inductance was 0.6 μH. Further, when a conventional copper wire, that is, a wire having a wire diameter of 22 μm was used, it could only be wound 17 times and a predetermined number of windings could not be obtained.

[0015]

【Example】

 (Examples 1 to 11) A tungsten wire having a diameter of 15 μm and a length of 1000 m is electrolytically polished by a known method to have a diameter of 8 to 12 μm. Next, an outer layer was formed on the wire thus obtained by electrolytic plating of copper having a thickness of 1.5 to 3.5 μm by a known method. Next, 0.5, 1.0 or 1.5 μm thick urethane is applied on the outer layer as an insulating coating, and the diameter of the composite metal wire with the insulating coating is set to 15 or 18 μm. The results are shown in Table 1. For example, in the case of Example 1, a tungsten wire is electropolished to have a diameter of 8 μm, and then, a copper wire having a thickness of 2.5 μm is electrolytically plated on the wire thus obtained to form an outer layer. Then, as the insulating coating, urethane having a thickness of 1.0 μm was applied on the outer layer, and the diameter of the composite metal wire having the insulating coating was set to 15 μm. The tensile strength was 20 g and the electric resistance was 190 Ω / m.

[0016]

[Table 1]

Comparative Example 1 A tungsten wire having a diameter of 15 μm and a length of 1000 m is electrolytically polished by a known method to have a diameter of 10 μm. Next, an outer layer was formed on the wire thus obtained by electrolytic plating with copper having a thickness of 1.5 μm. Next, 1.0 μm thick urethane was applied to the outer layer as an insulating coating, and the diameter of the insulating coated composite metal wire was set to 15 μm. Others were the same as in the example. Table 2 shows the results. The tensile strength was 25 g and the electric resistance was 330 Ω / m. (Comparative Example 2) A tungsten wire is electrolytically polished to a diameter of 13 μm. Next, an outer layer was formed on the wire thus obtained by electrolytic plating with copper having a thickness of 1.0 μm. Next, as the insulating coating, urethane having a thickness of 1.5 μm was applied on the outer layer, and the diameter of the insulating coated composite metal wire was set to 18 μm. Others were the same as in the example. Table 2 shows the results.

[0018]

[Table 2]

The following can be seen from Tables 1 and 2. Comparing Example 6 with Comparative Example 1, even if the outer layer has the same thickness, if the cross-sectional area of the outer layer is small, an electrical resistance of 300 Ω / m or less cannot be obtained. If the outer layer is made thicker and the inner layer is made smaller in order to reduce the electrical resistance, the tensile strength of the wire will be reduced. When the material forming the inner layer is tungsten, the lower limit of the diameter is 8 μm in order to satisfy the tensile strength of 20 g and the electric resistance of 300 Ω / m.

It is understood that, as shown in Table 3, electric resistance of 300 Ω / m or less cannot be obtained only by the electrolytically polished tungsten wire.

[Table 3]

[0021]

[Effect of device]

 As described above, according to the first aspect of the present invention, it is possible to obtain a composite metal wire having a wire diameter of 15 μm or less and having a tensile strength of 20 g or more for winding work. It was In the second invention of the present invention, an inductance of 0.6 μH could be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a composite metal wire showing an example of an embodiment of the present invention.

FIG. 2 is a front view of a core chip showing an example of an embodiment of the present invention.

FIG. 3 is a front view of a core chip using a conventional winding wire.

[Explanation of symbols]

 1 Inner Layer 3 Outer Layer 5 Insulation Coating 10 Core Chip 12 Winding Window 14 Coil of the Invention 16 Trailing Core 18 Leading Core 20 Magnetic Gap 22 Metal 24 Apex Glass 26 Protective Tube 28 Conventional Coil

Claims (6)

[Scope of utility model registration request] 1. A composite metal wire comprising an inner layer having a substantially circular cross-sectional shape and an outer layer of metal having a cylindrical cross-sectional shape, wherein the diameter of the composite metal wire including an insulating coating is 18 μm or less,
A composite metal wire having an electric resistance of 300 Ω / m or less. 2. The composite metal wire according to claim 1, wherein the inner layer is composed of a wire having a diameter of 12 μm or less and a tensile strength of 15 g or more. 3. The composite metal wire according to claim 1, wherein the inner layer is made of any one of a metallic material, a carbonaceous material, and an organic material. 4. The specific resistance of the outer layer is 6 × 10 ⁻⁸ Ω ·
Claim 1 thru | or Claim 3 comprised with the material below m.
7. The composite metal wire according to any one of 1. 5. The composite metal wire according to claim 1, wherein the composite wire having an insulating coating on the outer side of the outer layer has a tensile strength of 20 g or more. 6. A composite metal wire having a diameter of 18 μm or less and an electric resistance of 300 Ω / m or less, the inner layer having a substantially circular cross-sectional shape and the metal outer layer having a cylindrical cross-sectional shape. A composite type magnetic head characterized by being used as.