JP2002075734A - Magnetizing device for superconducting bulk material, and method for repetitively magnetizing the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetizing device for superconducting bulk material, which can fully magnetize a superconducting bulk material by making the coil and power unit used for impressing a magnetic field smaller in size, without requiring strong electromagnetic power, even during the course of magnetization. SOLUTION: The superconducting bulk material 1, carrying a heater wire 3 wound around the material 1, is arranged on a cooling apparatus 4, such as refrigerator head, etc. When an electric current is made to flow to the heater wire 3 from a power unit 5, which is preset to a current value through a switch 6 after the bulk material 1 is cooled entirely by means of the cooling apparatus 4, the bulk material 1 in the environs of the heat wire 3 is heated and the outer peripheral section of the material 1 will not go into superconducting state, but only the central part of the material 1 turns into a superconducting region. Therefore, the superconducting area can be magnetized as a whole even when a relatively small magnetic field is impressed upon the area. The whole body of the bulk material can be magnetized and a strong magnetic field can be generated, with a relatively small magnetic field by magnetizing the superconducting region by repetitively impressing the magnetic field upon the superconducting region, while the area is gradually expanded, by gradually reducing the value of the current supplied to the heater wire 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting bulk magnetizing apparatus and a method for repeatedly magnetizing the same.

[0002]

2. Description of the Related Art Conventional methods for magnetizing a superconducting bulk body include field cooling, zero field cooling, pulse magnetization, and the like. In zero field cooling and pulse magnetization, it is necessary to increase the magnetizing magnetic field. Although a method of repeatedly applying a magnetic field has been used, the temperature of the superconducting bulk body is constant, and magnetization is performed in the entire superconducting state.

[0003]

In the conventional method as described above, since a large magnetic field must be applied to magnetize the high-temperature superconducting bulk, the coil for the applied magnetic field and the power supply become large, And the influence on the outside becomes large, and a large electromagnetic force is generated in the magnetization.

In the present invention, the above problems are eliminated, and a relatively small magnetic field is repeatedly applied while gradually expanding the superconducting region of the superconducting bulk body, so that a coil and a power supply for the applied magnetic field are reduced, and the magnetization is reduced. It is an object of the present invention to provide a superconducting bulk body magnetizing device and a method of repeatedly magnetizing the same, which can perform sufficient magnetizing without requiring a large electromagnetic force in the process.

[0005]

In order to achieve the above object, the present invention provides: (1) a superconducting bulk body arranged in correspondence with a heating means in a superconducting bulk magnetizing apparatus; Means for sequentially increasing the superconducting state from a part of the whole to the whole.

[2] The superconducting bulk magnetizing device according to [1], wherein the heating means is a heater.

[3] The magnetizing device for a superconducting bulk body according to the above [2], wherein a heater wire is wound around the outer periphery of the superconducting bulk body.

[4] The magnetizing apparatus for a superconducting bulk body according to the above [2], wherein a plurality of heater wires are wound concentrically on the superconducting bulk body.

[5] The magnetizing apparatus for a superconducting bulk body according to the above [2], wherein a plurality of individually controllable heater wires are concentrically wound around upper and lower surfaces of the superconducting bulk body. .

[6] The apparatus for magnetizing a superconducting bulk body according to the above [2], wherein a surface heater is arranged at a local portion of the surface of the superconducting bulk body.

[7] The magnetizing apparatus for a superconducting bulk body according to the above [2], wherein a plurality of individually controllable surface heaters are arranged on the surface of the superconducting bulk body.

[8] The method of repeatedly magnetizing a superconducting bulk body is characterized in that the superconducting bulk body is magnetized by repeatedly applying a magnetic field while gradually increasing the superconducting state.

[0013]

[9] The method for repeatedly magnetizing a superconducting bulk body according to the above [8], wherein a portion in a superconducting state is concentrically increased from the center of the superconducting bulk body.

[10] The method for repeatedly magnetizing a superconducting bulk body according to the above [8], characterized in that a superconducting state portion is gradually increased from the end of the superconducting bulk body.

[11] The method for repeatedly magnetizing a superconducting bulk body according to the above [8], wherein the applied magnetic field is a pulsed or stationary magnetic field.

[0016]

Embodiments of the present invention will be described below in detail.

First, a superconducting bulk magnetizing device according to an embodiment of the present invention will be described.

FIG. 1 is a schematic view of a magnetizing device for a superconducting bulk body having a heater wire on an outer peripheral portion according to a first embodiment of the present invention.

In this embodiment, a heater wire 3 is wound around an outer peripheral portion 2 on a cooling device 4 which is mounted on a refrigerator head and cooled (may be cooled by directly immersing in a refrigerant such as liquid nitrogen). Superconducting bulk body 1 is placed.

Therefore, the entire superconducting bulk body 1 is cooled by the cooling device 4, and when a current is passed through the switch 6 from the power supply 5 having a preset current value to the heater wire 3, the heater wire 3 is heated. The superconducting bulk body 1 around is not heated to the superconducting state, and if only a small region inside the superconducting bulk body 1 is in the superconducting state, the entire portion of the superconducting state is magnetized even when a relatively small magnetic field is applied. be able to. Then, by gradually decreasing the current value of the heater wire 3, the superconducting state region of the superconducting bulk body 1 is repeated while gradually expanding as shown in FIG. If the magnetizing is performed, and finally the energization to the heater wire is stopped and a magnetic field is applied, the entire superconducting bulk body 1 can be magnetized.

FIG. 2 is a schematic view of a superconducting bulk body having a plurality of heater wires concentrically showing a second embodiment of the present invention.

As shown in FIG.
A plurality of heater wires 12, 13, 14 are concentrically wound.

Therefore, although not shown, the current flowing through the plurality of heater wires 12, 13, 14 is reduced by using the same cooling device and power supply device as in the first embodiment.
By stopping stepwise in the order of 13 and 14, magnetization can be repeatedly performed while the superconducting state region of the superconducting bulk body 11 is gradually enlarged from the center as shown in FIG. 7 (described later).

FIG. 3 is a schematic view of a superconducting bulk body having a plurality of heater wires concentrically provided on upper and lower surfaces according to a third embodiment of the present invention.

As shown in this figure, the superconducting bulk body 21
Heater wires 23, 24, 2 concentrically on the upper surface 22 of the
5 and a plurality of heater wires 27 concentrically on the lower surface 26 thereof.
28, 29 are wound.

Therefore, although not shown, the current flowing through the plurality of heater wires 23, 24, 25 and 27, 28, 29 is gradually applied using the same cooling device and power supply device as in the first embodiment. By stopping, the superconducting bulk 21
7 can be repeatedly magnetized while gradually expanding the superconducting region from the center as shown in FIG. 7 (described later).

FIG. 4 is a schematic diagram (part 1) of a superconducting bulk body provided with a surface heater according to a fourth embodiment of the present invention.
FIG. 4A is a schematic diagram of a superconducting bulk body having a surface heater at a local portion of its surface, and FIG. 4B is a schematic diagram of a superconducting bulk body having a plurality of surface heaters on its surface.

First, as shown in FIG. 4A, surface heaters 62 and 63 are arranged at a local portion of the surface of the superconducting bulk body 61.

Therefore, although not shown, the same heater and power supply as those in the first embodiment are used, and the surface heaters 62 and 62 are used.
By gradually decreasing the current flowing through 63, the magnetization can be repeatedly performed while the superconducting state region of superconducting bulk body 61 is gradually enlarged as shown in FIG. 9 (described later).

FIG. 4B shows a superconducting bulk body 71.
A plurality of surface heaters 72, 73, 74, 75 are arranged on the surface of the.

Therefore, although not shown, the current flowing through the plurality of surface heaters 72, 73, 74, 75 is gradually stopped by using the same cooling device and power supply device as in the first embodiment. Magnetization can be performed while expanding the superconducting region of the superconducting bulk body 71 stepwise as shown in FIG. 10 (described later).

FIG. 5 is a schematic diagram (part 2) of a superconducting bulk member having a surface heater according to a fourth embodiment of the present invention.
FIG. 5A is a schematic diagram of a superconducting bulk body having a surface heater at a local portion on a side surface thereof, and FIG. 5B is a schematic diagram of a superconducting bulk body having a plurality of surface heaters on its side surface.

First, as shown in FIG. 5A, a surface heater 82 is arranged at a local portion on the side surface of the superconducting bulk body 81.

Therefore, although not shown, the current flowing through the surface heater 82 is gradually reduced by using the same cooling device and power supply device as in the first embodiment, so that the superconducting state of the superconducting bulk body 81 is reduced. The magnetization can be repeatedly performed while gradually expanding the region.

FIG. 5B shows a superconducting bulk body 91.
A plurality of surface heaters 92, 93, 94, 95, 9
6,97 are arranged.

Therefore, although not shown, the current flowing through the plurality of surface heaters 92, 93, 94, 95, 96, and 97 is gradually applied using the same cooling device and power supply device as in the first embodiment. By stopping, the magnetization can be performed while the region of the superconducting state of the superconducting bulk body 91 is gradually expanded.

Hereinafter, a specific method of repeatedly magnetizing the superconducting bulk material of the present invention will be described.

FIG. 6 is a block diagram of a specific repetitive magnetizing apparatus for a superconducting bulk material according to the present invention.

In this figure, reference numeral 100 denotes a pulse tube refrigerator. This pulse tube refrigerator is connected to a compressor 102 and a vacuum exhaust device 103, and a head 101 of the pulse tube refrigerator has a high-temperature superconducting bulk under test. The body 104 is fixed.

A heater 105 is mounted on the test high-temperature superconducting bulk body 104 and is connected to a heater power supply 106. Also, the head 1 of the pulse tube refrigerator is used.
A temperature element 109 is set at 01 so that the temperature can be measured. Further, an electromagnetic coil 107 is arranged around the test high-temperature superconducting bulk body 104, and the electromagnetic coil 107 is connected to an excitation power supply 108. The strength of the magnetic field is measured by the Hall element 110.

As shown in FIG. 1, as shown in FIG. 1, as shown in FIG. 1, when a heater wire is wound around the outer periphery of the pulse tube refrigerator 100, the sample high-temperature superconducting bulk material 104 is set on the refrigerator head 101. The target temperature for cooling the test high-temperature superconducting bulk body 104 is kept constant at 80 K, and the current value of the heater wire is reduced stepwise to repeatedly pulse magnetize while gradually expanding the superconducting region from the center.

FIG. 7 is a view showing a method (part 1) for expanding the superconducting region of the superconducting bulk material according to the present invention.

First, as shown in FIG. 7A, the central portion of the high-temperature superconducting bulk body 51 is defined as a superconducting region 52, and then, as shown in FIG.
3. As shown in FIG. 7 (c), a further enlarged superconducting region 54 and finally a superconducting region 55 covering the entire high-temperature superconducting bulk body 51 are formed, and the magnetization is completed.

The measurement results when the above-described stepwise magnetization is performed are shown.

FIG. 8 is a view showing a measurement result obtained by a method (part 1) of expanding the superconducting region of the superconducting bulk body.

In this figure, the horizontal axis represents position (mm) and the vertical axis represents magnetic field (mT).
0A, 0.078A, 0.076A, 0.074A,
The magnet was magnetized in seven stages of 0.072A, 0.070A, and 0.068A.

FIG. 9 is a view showing a method (part 2) for expanding the superconducting region of the superconducting bulk material according to the present invention.

In this embodiment, the high-temperature superconducting bulk body 61
The surface heaters 62 and 63 are provided at the ends of the high-temperature superconducting bulk body 61 so as to gradually reduce the current, thereby expanding the superconducting region from the end of the high-temperature superconducting bulk body 61. FIG.
As shown in (a) to (d), the superconducting region is gradually enlarged from the end. That is, the superconducting region 64 → 65 → 66 →
67.

As shown in FIG. 10, a large number of surface heaters 72, 73, 7 are provided on the surface of the high-temperature superconducting bulk body 71.
The superconducting region of the high-temperature superconducting bulk body 71 is enlarged by disposing 4,75. That is, as shown in FIGS. 10A to 10D, the superconducting region 76 can be gradually expanded from 77 to 78 to 79.

The measurement results when stepwise magnetization is performed from the end of the superconducting bulk body as described above are shown.

FIG. 11 is a diagram showing the measurement results obtained by a method (part 2) for expanding the superconducting region of such a superconducting bulk body.

The high-temperature superconducting bulk body is attached to the refrigerator head, and as a method for attaching the heater, when one heater is arranged on the surface of the superconducting bulk body 61 shown in FIG. 9, the high-temperature superconducting bulk body is cooled by the refrigerator. The measurement result is shown in the case where the target temperature to be heated is kept constant at 80 K, and the current value of the heater is gradually reduced so that the superconducting region is repeatedly pulse-magnetized while extending from the end.

In this figure, the horizontal axis represents position (mm) and the vertical axis represents magnetic field (mT).
5A, 0.053A, 0.051A, 0.049A,
Magnetization was performed in seven steps of 0.047A, 0.045A, and 0A.

For comparison, the temperature of the entire high-temperature superconducting bulk was kept constant at 80 K, and pulse magnetization was repeated without controlling the superconducting region.

FIG. 12 shows the measurement results when the superconducting region was kept constant without being controlled. In FIG. 12, the number of times (1 to 5 times) the pulse magnetic field is applied is shown as a parameter.

As described above, when the superconducting region is kept constant without being controlled, no increase in the magnetic field is observed even when repeated pulse magnetization is attempted, and the maximum value of the magnetic field is 5 mT or less.

On the other hand, when the pulse magnetization is repeatedly performed while controlling and expanding the superconducting region, the magnetic field increases by repetition as shown in FIGS. 8 and 11, and the maximum value of the magnetic field is reduced to about 30 mT. Reach.

The shape of the superconducting bulk body is not limited to a cylinder, but can be adapted to various shapes such as a rectangular flat plate. In addition, how to expand the superconducting region can be controlled optimally depending on the characteristics of the superconductor and the magnitude of the applied magnetic field, and the control method is not limited to the example shown.

Although the above-described superconducting bulk body has a large thickness, even a thin superconducting body is included in the superconducting bulk body of the present invention.

Further, as a heating means, not shown,
A hot air device may be arranged near the superconducting bulk body to heat a local portion of the superconducting bulk body.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0062]

As described above in detail, according to the present invention, the magnetic field applied when magnetizing the superconducting bulk body can be reduced, so that the coil and power supply for the applied magnetic field can be reduced in size and size.
Lighter weight and less influence on the surroundings and outside.

Further, the electromagnetic force generated in the superconducting bulk body and the coil for applied magnetic field when magnetized can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a magnetizing device for a superconducting bulk body having a heater wire on an outer peripheral portion according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a superconducting bulk body provided with a plurality of heater wires concentrically showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a superconducting bulk body provided with a plurality of heater wires concentrically on upper and lower surfaces according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram (part 1) of a superconducting bulk body provided with a surface heater according to a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram (part 2) of a superconducting bulk body provided with a surface heater according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a specific repetitive magnetizing apparatus for a superconducting bulk body of the present invention.

FIG. 7 is a view showing a method (part 1) for expanding a superconducting region of a superconducting bulk body of the present invention.

FIG. 8 is a diagram showing a measurement result obtained by a method (part 1) for expanding a superconducting region of a superconducting bulk body according to the present invention.

FIG. 9 is a view showing a method (part 2) for expanding the superconducting region of the superconducting bulk body of the present invention.

FIG. 10 is a view showing a method of arranging a plurality of heaters in the superconducting bulk body of the present invention and enlarging the superconducting region of the high-temperature superconducting bulk body.

FIG. 11 is a diagram showing measurement results obtained by a method (part 2) for expanding a superconducting region of a superconducting bulk body according to the present invention.

FIG. 12 is a diagram showing a measurement result when a superconducting region is fixed without being controlled.

[Explanation of symbols]

1,11,21,51,61,71,81,91 Superconducting bulk body 2 Outer perimeter 3,12,13,14,23,24,25,27,2
8, 29 Heater wire 4 Cooling device (refrigerator head) 5 Power supply device 6 Switch 22 Upper surface 26 Lower surface 62, 63, 72, 73, 74, 75, 82, 92, 9
3, 94, 95, 96, 97 surface heaters 52, 53, 54, 55, 64, 65, 66, 67, 7
6, 77, 78, 79 Superconducting region 100 Pulse tube refrigerator 101 Refrigerator head 102 Compressor 103 Vacuum exhaust device 104 Test high temperature superconducting bulk body 105 Heater 106 Heater power supply 107 Electromagnetic coil 108 Excitation power supply 109 Temperature element 110 Hall element

Claims (11)

[Claims] 1. A superconducting bulk body arranged corresponding to a heating means, and (b) means for sequentially expanding a superconducting state from a part of the superconducting bulk body to the whole. Superconducting bulk magnetizer. 2. The superconducting bulk magnetizing device according to claim 1, wherein said heating means is a heater. 3. A magnetizing device for a superconducting bulk body according to claim 2, wherein a heater wire is wound around an outer peripheral portion of said bulk superconducting body. 4. A magnetizing device for a superconducting bulk body according to claim 2, wherein a plurality of heater wires are wound concentrically on said bulk superconducting body. 5. The superconducting bulk magnetizing device according to claim 2, wherein a plurality of individually controllable heater wires are concentrically wound around upper and lower surfaces of the superconducting bulk. Body magnetizing device. 6. A magnetizing apparatus for a superconducting bulk body according to claim 2, wherein a surface heater is arranged at a local portion of the surface of said bulk superconducting body. 7. The superconducting bulk magnetizing device according to claim 2, wherein a plurality of individually controllable surface heaters are arranged on the surface of the superconducting bulk. . 8. A method for repeatedly magnetizing a superconducting bulk body, characterized in that the superconducting bulk body is magnetized by repeatedly applying a magnetic field while gradually increasing the superconducting state of the superconducting bulk body. 9. The method for repetitively magnetizing a superconducting bulk body according to claim 8, wherein a portion in a superconducting state is concentrically increased from the center of the superconducting bulk body. Magnetization method. 10. The repetitive magnetizing method for a superconducting bulk body according to claim 8, wherein a portion in a superconducting state is gradually increased from an end of the bulk superconducting body. Magnetization method. 11. The method for repeatedly magnetizing a superconducting bulk body according to claim 8, wherein the applied magnetic field is a pulsed or stationary magnetic field.