JPH065646B2 - Superconductor magnetic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention suppresses the divergence of magnetic flux by using the characteristics of superconductivity,
The present invention relates to a superconductor magnetic device having a coil that conducts without leakage or attenuation and that shields the change of the internal magnetic flux and efficiently interacts with the magnetic flux.

<Conventional technology> Conventionally, when conducting or concentrating or converging magnetic flux, depending on the purpose, iron, silicon steel, or high permeability such as permalloy or ferrite, high saturation density, or low A method using a lossy magnetic material was used.

FIG. 3 shows a conventional example in which a magnetic flux is converged by a high-permeability material 3. In a magnetic field 1, the central area 7 of the magnetic field 1 has a small cross-sectional area and the end portions 6 have large cross-sectional areas. The body 5 is placed and the magnetic flux is converged at the center thereof.
As an example, even if soft iron is used for the magnetic body 5, its magnetic permeability is significantly larger than that of air, so that the magnetic flux could be converged and conducted. As the high magnetic permeability material, there have been transformer cores made of silicon steel or the like, motor magnetic cores, or small coils or transformers made of ferrite or the like, or magnetic head cores.

<Problems to be Solved by the Invention> When a magnetic material having a high magnetic permeability conducts or converges a magnetic flux, the magnetic material has a considerably high magnetic permeability, but in reality, the magnetic material has a finite magnetic permeability. , The magnetic flux was leaking.
The ratio of the magnetic flux passing through the magnetic material and the magnetic flux leaking through the air is
It changes depending on the ratio of the magnetic permeability of the magnetic material and air, and the shape of the magnetic circuit composed of the magnetic material, so that the magnetic flux transmissivity is reduced by the leakage magnetic flux, and further, the external noise magnetic field is spread and used. When the frequency is high, it may be a source of harm such as loss due to eddy current in the core and noise due to electromagnetic induction.

The present invention solves the above-mentioned problems of the magnetic circuit system by the conventional magnetic material by using the characteristics of the superconductor, and the magnetic flux is free from problems such as magnetic flux leakage, noise, and loss. The present invention provides a device using the above conduit.

<Means for Solving Problems> The present invention is to conduct or converge a magnetic flux without leaking it due to the Meissner effect of a superconductor, especially a recently developed ceramic high-temperature superconductor.

Since the superconductor is a perfect diamagnetic material, the magnetic field does not penetrate into it. Therefore, the superconducting conduit having a passage having a shape that does not reflect or scatter lines of magnetic force conducts the internal magnetic flux without leakage, and makes the magnetic flux density inversely proportional to the cross-sectional area of the conduit.

If the superconductor of this magnetic flux conduit is continuous over its entire circumference, a reflux current that shields changes in the magnetic flux inside will flow, so that the superconductor of this magnetic flux conduit will have An insulating layer was formed at least at one position along the entire length to prevent the shielding current from flowing.

When a coil for closely contacting the inner surface of the magnetic conduit of the present invention with the generation of magnetic flux in the conduit or for detecting the magnetic flux is formed,
A mirror image current is generated in the superconductor layer against the current of the coil, which disturbs the interaction between the magnetic flux and the coil.Therefore, either remove the superconductor in the conduit part of the coil or superconduct only the installation part of the coil. The body layers were separated to reduce the effect of the mirror image current.

<Operation> In the present invention, at least the inside of a conduit that conducts magnetic flux is made of a superconductor to prevent the magnetic flux from scattering and reflecting, thereby eliminating leakage and reflection of the magnetic flux from the conduit, and In this configuration, the reflux current that blocks the change in magnetic flux is blocked, and the magnetic effect of the mirror image current generated in the supercurrent body layer by the coil of the conduit is reduced. Among them, the magnetic flux can be used effectively. Also, noise due to electromagnetic induction is not emitted to the outside of this device, and no external noise radio wave is allowed to enter the inside of the conduit of the magnetic flux inside this device. Therefore, even if the device of the present invention is used in close proximity, problems such as crosstalk do not occur.

<Example> An example of the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing the principle of the present invention and corresponds to the conventional example of FIG. Reference numeral 2 in this figure is a longitudinal sectional view of a conduit whose inner surface is made of a superconductor, and the central portion of the conduit 2 is narrowed. When the magnetic flux 1 is introduced into this, the magnetic flux 1 is the Meissner effect due to the conduit 2 of the superconductor,
Completely reflected. Therefore, even if the conduit 2 becomes thinner in the middle portion and has a smaller cross-sectional area, the magnetic flux is completely reflected on the inner surface of the superconductor conduit 2 and thus does not leak.
It can be increased in inverse proportion to the area in the small cross-sectional area. (However, the magnetic field of the converged magnetic flux is in the range below the critical magnetic field Hc.) Therefore, if the superconducting conduit is shaped so that the magnetic flux is not scattered or reflected geometrically, the magnetic flux is transmitted without leakage. To be done.

In addition, magnetism does not enter from the outside into the conduit of this superconductor.

Further, although not shown, if an insulating layer is formed at least at one location along the magnetic flux 1 of the superconducting conduit 2 in this figure, a reflux current that prevents the change of the magnetic flux 1 is not generated.

FIG. 1 (a) is a cross-sectional view of an embodiment in which the present invention is applied to a transformer 11. In a hollow donut-shaped superconductor conduit 2, an input coil 4 for generating a torus-shaped magnetic flux 1 and a magnetic flux 1 are provided. Is provided with an output coil 4'for generating an induced current.

FIG. 1 (b) is a sectional view taken along the line AA ′ of FIG. As shown in this figure, the superconducting conduit 2 is provided with two insulating layers 3 along the magnetic flux 1 inside, and when this is not present, the superconducting tube 2 is shielded from the change in the magnetic flux 1 inside. The generated reflux current is blocked.

The superconductor layer 2 is removed from the coils 4 and 4'of the transformer 11 and the coils are wound around a non-magnetic tube.
This is because when there is a superconductor in the vicinity of the current in the coils 4 and 4 ', a mirror image of the current in the coil flows in that superconductor,
This is because there is an inductance reducing effect that weakens the interaction between the coil and the magnetic flux, and this adverse effect is avoided. Even if the superconducting layers of the coils 4, 4'are removed, if the winding density of the conductor coil is increased, the magnetic flux 1 may leak,
Magnetic flux that becomes noise from the outside rarely enters.

For convenience of making the coils 4 and 4'of the transformer 11 of the above-mentioned embodiment, only the portions of the coils 4 and 4'are made of another non-magnetic material to wind the coil, and the superconducting conduit 2 is connected. Then, the transformer 11 was manufactured.

When a current i _{1 is} passed through this input coil 4, a magnetic flux 1 generated
Are completely reflected by the inner surface of the hollow donut-shaped conduit 2, so that they all penetrate the output coil 4 ′ and generate an induced current i ₂ .

Since the transformer 11 of the present invention has no conventional magnetic material core, there is no loss due to the eddy current generated in the conventional core. If the input coil 4 and the output coil 4'of this transformer are made of the same superconductor wire material or foil material, no loss occurs in the current of the coil or the conduit of the magnetic flux, so that a transformer with very good conversion efficiency is produced. can do.

It is not necessary to make all the conduits 2 of the magnetic flux 1 used in the present invention from superconductors. If the superconductors made inside this conduit have a thickness that completely reflects the magnetic field due to the Meissner effect, the superconducting The outside of the body can be composed of any material. Recently developed yttrium-barium-copper oxide (Yc) with a higher critical temperature (Tc) than before (Y
If it is a superconductor of -Ba-Cu-O), Tc is 95K, so it can be used by cooling with liquid nitrogen (77K). Also, T
If a superconductor having a higher c is developed, a transformer that is easier to use can be constructed.

In order to become completely diamagnetic due to the Meissner effect, the superconductor must have at least the depth of its magnetic field penetration (10 ^-8 to 10 ^-7 m).
It is necessary to form the above film, and in an oxide superconductor such as Y-Ba-Cu-O, it is also necessary to control the oxygen composition ratio by performing heat treatment in which the atmosphere, temperature, etc. are adjusted. Therefore,
A superconductor material was formed into a film by a thin film or thick film method on the inner surface of a non-magnetic and heat-resistant ceramic or metal molded product, and a heat treatment was used to form a superconductor film.

In this embodiment, an alumina molded product (not shown) whose inner surface has the shape of the superconducting conduit 2 is cut at a portion of the insulating layer 3, and Y-Ba-Cu-O is sputtered on the inner surface of the product by 3 to 5 μm. After being attached to a film having a thickness of, a heat treatment was performed to form a superconductor film.

The alumina molded product to which the superconductor film was attached was bonded at the insulating layer 3 portion with an insulating adhesive to form the conduit 2.

In addition to alumina, stabilized zirconia, silica, or heat-resistant steel having a thermal expansion coefficient close to that of ceramic can be used as the material of the molded product to which the superconductor film of the superconductor conduit 2 is attached in the present invention.

Further, a CVD method, a vapor deposition method, a spray pyrolysis method, or the like can be used for manufacturing the superconductor film, and the superconductor is also Tl-Ca-Ba-CuO or Bi-Sr other than Y-Ba-Cu-O. −Ca
An oxide superconductor such as -Cu-O can be used.

FIG. 4 shows a second embodiment in which the present invention is applied to a magnetic head. FIG. 4 (a) is a vertical sectional view of the magnetic head 12 and FIG. 4 (b) is a sectional view of FIG. It is a -B 'sectional view. The superconducting conduit 2 of this magnetic head 12 is also formed of a ceramic superconductor film on a ceramic molding, as in the previous transformer embodiment.
It was created by a method of joining at the insulating layer 3. This conduit has two parallel elongated openings perpendicular to the running direction of the tape on the side in contact with the magnetic tape 8 and a coil 4 is provided by removing a part of the superconductor layer of the conduit 2. ing. With the magnetic head 12 having this structure, the magnetic recording layer 9 is formed on the base film 10 of the magnetic tape 8 from the opening of the magnetic flux 1 generated by the coil 4 without leaking in the conduit 2 for writing. Recorded in. For reading, the magnetic flux 1 generated by the magnetic field recorded in the magnetic recording layer 9 passes through the conduit 2 from the opening, passes through the coil 4, and generates an induced current in the coil 4. In this magnetic head as well, the magnetic flux 1 is transmitted without leakage between the coil 4 and the magnetic recording layer 9 by the superconductor conduit 2, and the current flowing through the coil 4 does not generate a mirror image current in the superconductor layer. Therefore, the decrease in the interaction between the coil 4 and the magnetic flux 1 is small.

Although the horizontal magnetic recording and the reading of the magnetic head of FIG. 4 have been described above, the magnetic head shape and the characteristics of the magnetic tape can be changed to be applied to the perpendicular magnetic recording.

The coil used for the transformer 11 and the magnetic head 12 can prevent the leakage of the internal magnetic flux by tightly winding a metal wire around the non-magnetic tube or by winding the metal wire in multiple layers. It is also possible to prepare a superconducting film of (1) and make it a normal conductor by photo-etching, laser beam irradiation or the like, and make the superconducting portion into a coil to form a coil.

If the coil 4 of the magnetic head 12 shown in FIG. 4 is a solid-state magnetic sensor, a read-only magnetic head can be obtained. At this time, the conduit other than the opening may be a superconductor conduit. Further, both the coil and the solid magnetic head described above can be incorporated in one magnetic head.

FIG. 5 shows an example of a cross section of the superconductor conduit 2 other than the above example.

This (a) figure shows a structure in which the superconducting layers of the conduit 2 overlap each other in the insulating layer portion, and the (b) figure shows an example in which two or more (4 in the example) insulating layers are formed in the superconducting layer. Is. Also, (c)
The figure shows a structure in which leakage of magnetic flux is prevented by forming two layers of superconductor layers 2 and shifting the insulating separation portion between the inner layer and the outer layer.

As in the above example, since the superconductor device of the present invention does not use the magnetic core, there is no loss due to eddy current due to the change in magnetic flux as in the conventional case.

<Effects of the Invention> The superconductor magnetic device of the present invention is a magnetic flux conduit of a superconductor that conducts a magnetic flux without leaking, and does not generate a shielding current due to a change in the magnetic flux or a mirror image current due to a coil current in a superconductor layer. With the configuration, the device can efficiently use the magnetic flux up to an extremely high frequency.

[Brief description of drawings]

FIG. 1 is a sectional view of a transformer of a first embodiment of the present invention, FIG. 2 is a sectional view of a conduit for explaining the basics of the present invention, and FIG. 3 is a conventional example corresponding to FIG. FIG. 4 is a sectional view of a magnetic head according to a second embodiment of the present invention, and FIG. 5 is a sectional view of another example of the magnetic conduit. 1 is a magnetic flux, 2 is a superconducting conduit, 3 is an insulating layer, 4 and 4'coils, 5 is a magnetic material, 6 is an end of a magnetic material, 7 is a central part of the magnetic material, 8 is a magnetic tape, and 9 is Recording part of magnetic tape, 1
Reference numeral 0 is a magnetic tape base, 11 is a transformer, and 12 is a magnetic head.

Claims (3)

[Claims] 1. A superconductor for preventing the generation of a reflux current for interrupting the change of the magnetic flux in a conduit having an inner surface of a superconductor having a thickness of at least complete diamagnetic and converging and passing the magnetic flux therein. An insulating layer is provided along the magnetic flux inside the layer, and in order to prevent the influence of the mirror image current generated in the superconductor layer close to the current of the coil provided in the magnetic circuit of the magnetic flux, the superconductor layer is partially formed. A superconductor magnetic device characterized by being removed or changed in shape. 2. The insulating layer for interrupting the return current path of the superconductor magnetic device is provided in the conduit at least at one position along the magnetic flux inside the conduit. Superconductor magnetic device. 3. A superconductor layer of the superconductor magnetic device is removed in order to prevent a current generated in the superconductor layer of the superconductor magnetic device from being mirror-imaged by the current of the coil, or the influence of the magnetic field of the coil is eliminated. The superconducting magnetic device according to claim 1, wherein the superconducting magnetic device is separated to a small number of positions.