JPH03166795A - Magnetic shield material - Google Patents
Magnetic shield materialInfo
- Publication number
- JPH03166795A JPH03166795A JP30729189A JP30729189A JPH03166795A JP H03166795 A JPH03166795 A JP H03166795A JP 30729189 A JP30729189 A JP 30729189A JP 30729189 A JP30729189 A JP 30729189A JP H03166795 A JPH03166795 A JP H03166795A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- superconductor
- film
- buffer layer
- ferromagnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 118
- 239000000463 material Substances 0.000 title claims abstract description 42
- 239000002887 superconductor Substances 0.000 claims abstract description 55
- 230000005294 ferromagnetic effect Effects 0.000 claims abstract description 18
- 239000006185 dispersion Substances 0.000 claims abstract description 7
- 239000010419 fine particle Substances 0.000 claims description 24
- 239000003302 ferromagnetic material Substances 0.000 claims description 14
- 230000000694 effects Effects 0.000 abstract description 7
- 239000012212 insulator Substances 0.000 abstract description 7
- 239000000126 substance Substances 0.000 abstract description 6
- 230000002500 effect on skin Effects 0.000 abstract description 4
- 230000015556 catabolic process Effects 0.000 abstract 1
- 239000000696 magnetic material Substances 0.000 description 23
- 230000004907 flux Effects 0.000 description 17
- 230000005415 magnetization Effects 0.000 description 8
- 230000007704 transition Effects 0.000 description 8
- 230000006872 improvement Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 229910021521 yttrium barium copper oxide Inorganic materials 0.000 description 5
- 239000004020 conductor Substances 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000005381 magnetic domain Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000005298 paramagnetic effect Effects 0.000 description 2
- 229910000889 permalloy Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000005292 diamagnetic effect Effects 0.000 description 1
- 239000002889 diamagnetic material Substances 0.000 description 1
- -1 grain boundaries Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 239000002120 nanofilm Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 230000005408 paramagnetism Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
Landscapes
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
Description
【発明の詳細な説明】 （発明の産業上利用分野） 本発明は、磁気シールド材に関するものである。[Detailed description of the invention] (Field of industrial application of the invention) The present invention relates to a magnetic shielding material.
（従来の技術）
磁気シールド効果を示す材料としては、強磁性体および
反磁性体があり、従来は高い透磁率を有す強磁性体が磁
気シールド材として使用されてきた。近年これに代わり
、強い反磁性を示す超伝導体が軽量でシールド効果の高
い磁気シールド材として有望視されている。(Prior Art) Materials that exhibit a magnetic shielding effect include ferromagnetic materials and diamagnetic materials. Conventionally, ferromagnetic materials with high magnetic permeability have been used as magnetic shielding materials. In recent years, superconductors that exhibit strong diamagnetic properties have been shown to be promising as lightweight and highly effective magnetic shielding materials.
超伝導体を磁気シールドに応用する場合、最大磁気シー
ルド量は超伝導体の臨界電流密度（Ｊｃ）に比例するた
め、Ｊｃが高いことが必要となる。When a superconductor is applied to a magnetic shield, the maximum amount of magnetic shielding is proportional to the critical current density (Jc) of the superconductor, so it is necessary that Jc be high.
また、特に弱磁場に対するシールドでは、Ｊｃが高いこ
との他に、超伝導体内部の磁気ゆらぎが小さいことが要
求される。In addition, especially for shielding against weak magnetic fields, in addition to high Jc, it is required that magnetic fluctuations inside the superconductor be small.
Ｊｃは超伝導体に侵入した磁束線に働くローレンッ力と
ビン止め力とのつり合いによって決定する。したがって
、Ｊｃを向上させるためにはピン止め力が強いことが必
要である．また、磁気ゆらぎは超伝導体に侵入した磁束
線のゆらぎが原因であるため、これを抑えるにはやはり
ビン止め力が強いことが有効である。Jc is determined by the balance between the Lorent force and the bottle-stopping force that act on the magnetic flux lines that have entered the superconductor. Therefore, in order to improve Jc, it is necessary to have strong pinning force. Furthermore, since magnetic fluctuations are caused by fluctuations in magnetic flux lines that have entered the superconductor, it is effective to have a strong binding force in order to suppress this.
（発明が解決する問題点）
超伝導体のビン止め力は、材料固有のものではなく、作
製法・加工法を工夫しピン止め中心となる粒界、析出物
、転位などの不均質点を多数形成することにより強くす
ることができる。しかし、不均質点をピン止め中心とす
る方法は、不均質点を超伝導体内に形戒するため、超伝
導特性をかえって劣化させる恐れがある。特に近年発見
された酸化物超伝導体は、超伝導転移温度および上部臨
界磁場が高く磁気シールド材として有望であるものの、
その超伝導特性が組成および結晶構造の変化に非常に敏
感であるため、良好な超伝導特性を維持したまま適当な
不均質点を形成することが困難となっている．
本発明は、上述の問題点に鑑みなされたものであり、従
来の超伝導体に見られたビン止め力の弱さを解決し、磁
気シールド効果が大きく、磁気ゆらぎの少ない超伝導体
を用いた磁気シールド材を提供することを目的とする。(Problems to be solved by the invention) The pinning force of superconductors is not inherent to the material, but is achieved by devising manufacturing and processing methods to reduce inhomogeneous points such as grain boundaries, precipitates, and dislocations, which are the pinning centers. It can be made stronger by forming a large number of them. However, the method of pinning the inhomogeneous point as the center of pinning causes the inhomogeneous point to be formed within the superconductor, which may actually deteriorate the superconducting properties. In particular, oxide superconductors discovered in recent years have high superconducting transition temperatures and upper critical magnetic fields, and are promising as magnetic shielding materials.
Since its superconducting properties are very sensitive to changes in composition and crystal structure, it is difficult to form suitable inhomogeneous points while maintaining good superconducting properties. The present invention was made in view of the above-mentioned problems, and it solves the weak binding force observed in conventional superconductors, and uses a superconductor that has a large magnetic shielding effect and little magnetic fluctuation. The purpose of this study is to provide magnetic shielding materials with high quality.
（問題点を解決するための手段）
上記問題点を解決するため、本発明による磁気シールド
材は、超伝導体に直接あるいは非磁性、非超伝導性を有
するバッファ層を介して、強磁性体を形成したことを特
徴とする。(Means for Solving the Problems) In order to solve the above problems, the magnetic shielding material according to the present invention has a magnetic shielding material that uses a ferromagnetic material directly on a superconductor or through a non-magnetic, non-superconducting buffer layer. It is characterized by the formation of
本発明による第二の磁気シールド材は、超伝導体面に直
接あるいは非磁性、非超伝導性を有するバッファ層を介
して強磁性微粒子分散膜を形成したことを特徴とする。The second magnetic shielding material according to the present invention is characterized in that a ferromagnetic fine particle dispersed film is formed on the superconductor surface directly or via a nonmagnetic, nonsuperconducting buffer layer.
本発明による第三の磁気シールド材は、超伝導体面に直
接あるいは非磁性、非超伝導性を有するバッファ層を介
して強磁性体あるいは強磁性微粒子分散材を島状に形成
したことを特徴とする。A third magnetic shielding material according to the present invention is characterized in that a ferromagnetic material or a ferromagnetic fine particle dispersion material is formed in an island shape on a superconductor surface directly or via a nonmagnetic, nonsuperconducting buffer layer. do.
従来のシールド材は、ビン止め中心として粒界、析出物
、転位などの材料内の不均質点を有した超伝導体を利用
していたが、本発明の磁気シールド材は、超伝導体外部
に隣接した前記強磁性体の磁化をビン止め中心とした超
伝導体と強磁性体とからなる複合材料である点が異なる
。Conventional shielding materials used superconductors with inhomogeneity points within the material, such as grain boundaries, precipitates, and dislocations, as the center of binding, but the magnetic shielding material of the present invention uses The difference is that it is a composite material consisting of a superconductor and a ferromagnetic material, with the magnetization of the ferromagnetic material adjacent to the ferromagnetic material being centered.
本発明をさらに詳しく説明すると、本発明による磁気シ
ールド材は、超伝導体面に直接あるいは非磁性、非超伝
導性を有するバツファ層を介して強磁性体を設けたもの
である。To explain the present invention in more detail, the magnetic shielding material according to the present invention is one in which a ferromagnetic material is provided on a superconductor surface directly or via a buffer layer having non-magnetic and non-superconducting properties.
強磁性体の設ける方法、形態は本発明において基本的に
限定されるものではなく、強磁性体膜であってもよく、
強磁性を有する微粒子を分散させた膜（以下強磁性微粒
子分散膜という）であってもよい．また、前記強磁性体
を部分的に設けても同様な効果がえられる。すなわち強
磁性体く強磁性微粒子分散材を含む〉を島状に形成して
もよい．（実施例１〉
第１図および第２図は、本発明の第１の実施例を説明す
る図であり、１は超伝導体、２は磁性体膜、３はバッフ
ァ層である。The method and form of providing the ferromagnetic material are not fundamentally limited in the present invention, and a ferromagnetic film may be used.
It may also be a film in which ferromagnetic fine particles are dispersed (hereinafter referred to as a ferromagnetic fine particle dispersed film). Moreover, the same effect can be obtained even if the ferromagnetic material is partially provided. In other words, a ferromagnetic material containing a ferromagnetic fine particle dispersion material may be formed into an island shape. (Example 1) FIGS. 1 and 2 are diagrams explaining a first example of the present invention, in which 1 is a superconductor, 2 is a magnetic film, and 3 is a buffer layer.
磁性体膜２は、導電体でも絶縁体でも構わないが、超伝
導体１を高周波領域で応用する場合には、表皮効果を考
慮して絶縁体の方が有利である。また、磁性体膜２の保
磁力は高い方がピン止め力が高磁場においても働く点で
有利である。なお、磁性体６が発生する磁場による超伝
導状態の破壊、および磁性体６と超伝導体１との接合面
での拡散の恐れのある場合には、これを防ぐため両者の
間にバッファ層３を導入する。バッファ層３としては、
非磁性、非超伝導である材料を使用する。The magnetic film 2 may be a conductor or an insulator, but when the superconductor 1 is applied in a high frequency region, an insulator is more advantageous in consideration of the skin effect. Further, it is advantageous that the coercive force of the magnetic film 2 is higher in that the pinning force works even in a high magnetic field. In addition, if there is a risk of destruction of the superconducting state due to the magnetic field generated by the magnetic material 6 or diffusion at the junction surface between the magnetic material 6 and the superconductor 1, a buffer layer is placed between the two to prevent this. Introducing 3. As the buffer layer 3,
Use materials that are non-magnetic and non-superconducting.
強磁性体は強磁性転移温度（Ｔｍ）以上では自発磁化を
形成せず保磁力が零の常磁性を示す。一方、Ｔｍ以下で
は強磁性状態となり、高保磁力磁性体の場合にはその磁
ｆヒ曲線は第３図のようにヒステリシスを示し、また自
発磁化を形成するようになる。A ferromagnetic material does not form spontaneous magnetization above the ferromagnetic transition temperature (Tm) and exhibits paramagnetism with a coercive force of zero. On the other hand, below Tm, the material becomes ferromagnetic, and in the case of a high coercive force magnetic material, its magnetic f curve exhibits hysteresis as shown in FIG. 3, and spontaneous magnetization occurs.
次に、第ｌ図に示した構成の材料を例にとり、磁性体膜
２によるビン止め機構について第４図で説明する。温度
が超伝導＃．１の超伝導転移温度（Ｔｃ）よりも低く、
かつ上記Ｔｍよりも高い場合、超伝導体１は超伝導状態
に、磁性体膜２は常磁性状態にある。超伝導体１および
磁性体膜２には磁束線４が通過している。この温度範囲
では磁性体膜２は磁化しないため、ピン止め力は磁性体
膜２がない場合と何ら変わらない。一方、温度がＴｍよ
りも低くなると、磁性体膜２は強磁性状態となり、磁束
線４が通過している領域では自発磁化が形成される。磁
性体膜２の保磁力が高い場合には、磁化領域５は外来磁
場およびローレンッ力によって容易に動かされなくなる
ため、磁束線４はこの磁化領域５にトラップされる。す
なわち、磁化領域５は強いピン止め中心として機能する
。Next, the bottle fixing mechanism using the magnetic film 2 will be explained with reference to FIG. 4, taking as an example the material having the structure shown in FIG. 1. Temperature is superconducting #. lower than the superconducting transition temperature (Tc) of 1,
When the temperature is higher than the above Tm, the superconductor 1 is in a superconducting state and the magnetic film 2 is in a paramagnetic state. Magnetic flux lines 4 pass through the superconductor 1 and the magnetic film 2 . Since the magnetic film 2 is not magnetized in this temperature range, the pinning force is the same as in the case where there is no magnetic film 2. On the other hand, when the temperature becomes lower than Tm, the magnetic film 2 becomes ferromagnetic, and spontaneous magnetization is formed in the region through which the magnetic flux lines 4 pass. When the coercive force of the magnetic film 2 is high, the magnetic flux lines 4 are trapped in the magnetized region 5 because the magnetized region 5 is not easily moved by an external magnetic field and the Lorent force. That is, the magnetized region 5 functions as a strong pinning center.
具体例として、超伝導体ＩとしてＹＢＣｏ厚膜を、磁性
体膜２として６９Ｋに強磁性転移温度を有すＥｕ○を用
いた例を示す。As a specific example, an example will be shown in which a YBCo thick film is used as the superconductor I, and Eu○ having a ferromagnetic transition temperature of 69K is used as the magnetic film 2.
ＹＢＣ○の超伝導転移温度である９１ＫではＥｕＯは常
磁性状体にあり、６９Ｋ以下では強磁性状態にある。４
０ＫでのＪｃは、ＹＢＣ○膜単独では１０００人／ｃｍ
２、ＹＢＣＯ膜の上にＥｕ○を積層させた膜では１２０
０人／ｃｍ２となった。４０ＫにおけるＥｕＯの保磁力
は１００エルステッドであった。このＪｃの向上から、
磁性体６の積層により超伝導体】のピン止め力が強くな
ったことがわかる。At 91 K, which is the superconducting transition temperature of YBC○, EuO is in a paramagnetic state, and below 69 K, it is in a ferromagnetic state. 4
Jc at 0K is 1000 people/cm for YBC○ membrane alone
2. 120 for a film in which Eu○ is laminated on a YBCO film
The number was 0 people/cm2. The coercive force of EuO at 40K was 100 Oe. From this improvement in Jc,
It can be seen that the pinning force of the superconductor becomes stronger due to the stacking of the magnetic material 6.
このように本発明による材料は従来の超伝導体と比較し
、磁気シールド材として必要な条件であるピン止め力の
強さの点で改善があった。As described above, the material according to the present invention has an improvement in the strength of pinning force, which is a necessary condition for a magnetic shield material, compared to conventional superconductors.
（実施例２）
実施例１で示した第１図から第４図は、本発明の第２の
実施例を説明する図としても適当であるから、重複を避
け、第１図から第４図を参照して説明する。この実施例
において、図中、１は超伝導体、２は磁性微粒子分散膜
、３はバッファ層を示す。(Example 2) Since FIGS. 1 to 4 shown in Example 1 are suitable as diagrams for explaining the second embodiment of the present invention, to avoid duplication, FIGS. Explain with reference to. In this example, in the figure, 1 is a superconductor, 2 is a magnetic fine particle dispersed film, and 3 is a buffer layer.
磁性微粒子分散膜２は、導電体でも絶縁体でも構わない
が、超伝導体を高周波領域で応用する場合には、表皮効
果を考慮して絶縁体の方が有利である。また、磁性微粒
子分散膜２の保磁力は高い方がビン止め力が高磁場にお
いても働く点で有利である。なお、磁性微粒子分散膜２
が発生する磁場による超伝導状態の破壊、および磁性微
粒子分散膜２と超伝導体１との接合面での拡散の恐れの
ある場合には、これを防ぐため両者の間にバッファ層３
を導入する。バッファ層３としては、非磁性、非超伝導
性である材料を使用する．
ここで、磁性微粒子はその粒子径がある寸法より小さく
なると、単磁区構造となる．この単磁区楕造を有する磁
性微粒子は、ある温度（Ｔｍ）以上では保磁力が零とな
る超常磁性状態を示し、またＴｍ以下では高保磁力を有
す強磁性状態となる。The magnetic fine particle dispersed film 2 may be a conductor or an insulator, but when a superconductor is applied in a high frequency region, an insulator is more advantageous in consideration of the skin effect. Further, the higher the coercive force of the magnetic fine particle dispersed film 2 is, the more advantageous it is in that the bottle-stopping force works even in a high magnetic field. In addition, magnetic fine particle dispersion film 2
If there is a risk of destruction of the superconducting state due to the generated magnetic field and diffusion at the interface between the magnetic fine particle dispersed film 2 and the superconductor 1, a buffer layer 3 is placed between the two to prevent this.
will be introduced. As the buffer layer 3, a non-magnetic, non-superconducting material is used. Here, when the particle size of a magnetic fine particle becomes smaller than a certain size, it becomes a single magnetic domain structure. Magnetic particles having this single domain ellipse exhibit a superparamagnetic state with a coercive force of zero above a certain temperature (Tm), and a ferromagnetic state with a high coercive force below Tm.
Ｔｍは一般に超常磁性転移温度と称される。第５図に単
磁区構造を有する磁性微粒子の超常磁性状態の磁化曲線
を示す。Tm is generally referred to as superparamagnetic transition temperature. FIG. 5 shows the magnetization curve of a superparamagnetic state of magnetic fine particles having a single magnetic domain structure.
次に、第１図に示した構或の磁気シールド材を例にとり
、磁性微粒子分散膜２によるピン止め機構について第４
図を用いて説明する。Next, using the magnetic shielding material having the structure shown in FIG.
This will be explained using figures.
ここで４は磁束線、５は磁化領域を示す。温度が超伝導
体Ｉの超伝導転移温度（Ｔｃ）よりも低く、かつ上記Ｔ
ｍよりも高い場合、超伝導体１は超伝導状態に、磁性微
粒子分散Ｈ２は超常磁性状態にある。したがって、超伝
導体１および磁性微粒子分散膜２には磁束線４が通過し
、磁性微粒子分散膜２の磁束線４が通過している領域は
磁化した状態となる。この温度範囲では磁性微粒子の保
磁力は零であるため、磁束線４および磁化領域５は外来
磁場およびローレンツ力によってたやすく移動し、この
磁化領域５は磁束線４に対する強いピン止め中心とはな
り得ない。一方、温度がＴｍより低くなると、磁性微粒
子分散膜２は高保磁力を有した強磁性状態となる。保磁
力が高いと、磁化領域５は外来磁場などによって容易に
は動かなくなり、したがって磁化領域５は強いビン止め
中心として機能する。Here, 4 indicates a magnetic flux line, and 5 indicates a magnetized region. temperature is lower than the superconducting transition temperature (Tc) of superconductor I, and the above T
When it is higher than m, the superconductor 1 is in a superconducting state and the magnetic fine particle dispersion H2 is in a superparamagnetic state. Therefore, the magnetic flux lines 4 pass through the superconductor 1 and the magnetic fine particle dispersed film 2, and the region of the magnetic fine particle dispersed film 2 through which the magnetic flux lines 4 pass becomes magnetized. Since the coercive force of magnetic fine particles is zero in this temperature range, the magnetic flux lines 4 and the magnetized region 5 are easily moved by the external magnetic field and the Lorentz force, and the magnetized region 5 is not a strong pinning center for the magnetic flux lines 4. I don't get it. On the other hand, when the temperature becomes lower than Tm, the magnetic fine particle dispersed film 2 enters a ferromagnetic state with a high coercive force. If the coercive force is high, the magnetized region 5 will not move easily due to an external magnetic field, etc., and therefore the magnetized region 5 will function as a strong pin-stopping center.
具体例として、超伝導体１としてＹＢＣ○厚膜を、磁性
微粒子分散膜２として直径２０人のγ−Ｆｅ２０３をパ
ラフィン中に分散した塗膜を用いた例を示す。ＹＢＣ○
厚膜のＴｃである９１Ｋでは、γ一Ｆｅ２０３微粒子は
保磁力０エルステッドの超常磁性状態にある。一方、７
７Ｋでは強磁性となりその保磁力は２００エルステッド
である。As a specific example, an example will be shown in which a YBC○ thick film is used as the superconductor 1, and a coating film in which γ-Fe203 with a diameter of 20 mm is dispersed in paraffin is used as the magnetic fine particle dispersed film 2. YBC○
At 91K, which is the Tc of the thick film, the γ-Fe203 fine particles are in a superparamagnetic state with a coercive force of 0 Oersteds. On the other hand, 7
At 7K, it becomes ferromagnetic and its coercive force is 200 Oe.
７７ＫでのＪｃは、ＹＢＣ○膜単独では６００人／ｃｍ
２、ＹＢＣＯ膜の上に７−Ｆ ｅ ２０３膜を積層させ
た膜では８００人／Ｃｍ２となった。Jc at 77K is 600 people/cm for YBC○ membrane alone
2. In a film in which a 7-F e 203 film was laminated on a YBCO film, the resistance was 800 people/Cm2.
このＪｃの向上から、磁性微粒子分散膜の積層により超
伝導体のビン止め力が強くなったことがわかる。This improvement in Jc indicates that the binding force of the superconductor was strengthened by laminating the magnetic fine particle dispersed film.
このように本発明による材料は従来の超伝導体と比較し
、磁気シールド材として必要な条件であるビン止め力の
強さの点で改善があった．（実施例３〉
第６図および第７図は、本発明の第３の実施例を説明す
る図であり、１は超伝導体、３はバツファ層、６は磁性
体である。磁性体６は超伝導体１の超伝導転移温度（Ｔ
ｃ）以下の温度で超伝導体上に島状に堆積させる．磁性
体６の各島は接触することなく堆積している。磁性体６
は、導電体でも絶縁体でも構わないが、超伝導体ｌを高
周波領域で応用する場合には、表皮効果を考慮して絶縁
体の方が有利である．なお、磁性体６が発生する磁場に
よる超伝導状態の破壊、および磁性体６と超伝導体１と
の接合面での拡散の恐れのある場合には、これを防ぐた
め両者の間にバッファ層３を導入する。バッファＮ３と
しては、非磁性、非超伝導である材料を使用する。As described above, the material according to the present invention has an improvement in the strength of the binding force, which is a necessary condition for a magnetic shield material, compared to conventional superconductors. (Example 3) FIGS. 6 and 7 are diagrams explaining the third example of the present invention, in which 1 is a superconductor, 3 is a buffer layer, and 6 is a magnetic material. Magnetic material 6 is the superconducting transition temperature (T
c) Deposit in island form on the superconductor at a temperature of: The islands of magnetic material 6 are deposited without contacting each other. Magnetic material 6
can be either a conductor or an insulator, but when applying superconductors in the high frequency range, an insulator is more advantageous in consideration of the skin effect. In addition, if there is a risk of destruction of the superconducting state due to the magnetic field generated by the magnetic material 6 or diffusion at the junction surface between the magnetic material 6 and the superconductor 1, a buffer layer is placed between the two to prevent this. Introducing 3. As the buffer N3, a non-magnetic, non-superconducting material is used.
次に第６図に示した構成の材料を例にとり、磁性体６に
よるピン止め機構について第８図に説明する．温度はＴ
ｃ以下であり、超伝導体１は超伝導状態にある。超伝導
体１には磁束線４が通過している（第８図）。この状態
の超伝導体１の上に磁性体６を堆積させると堆積の初期
には磁束線４が通過している領域のみに磁性体６は島状
に堆積する（第９図）．磁性体６の島が互いに接触する
前に堆積を停止する．この時磁性体６は磁束線４によっ
て磁化されている．磁性体６が軟磁性体か硬磁性体かに
かかわらず磁性体６と磁束線４の間には磁気的なクーロ
ン引力が働き、磁束線４は磁性体６の島にトラップされ
る。磁性体６は超伝導体１の上に付着しているため外来
磁場およびローレンツカによって動くことはない．した
がって、この島状磁性体は磁束線４に対する強いピン止
め中心として機能する。Next, the pinning mechanism using the magnetic body 6 will be explained with reference to FIG. 8, taking as an example the material of the configuration shown in FIG. 6. The temperature is T
c or less, and the superconductor 1 is in a superconducting state. Magnetic flux lines 4 pass through the superconductor 1 (FIG. 8). When the magnetic material 6 is deposited on the superconductor 1 in this state, at the beginning of the deposition, the magnetic material 6 is deposited in the form of islands only in the area where the magnetic flux lines 4 pass (Figure 9). Deposition is stopped before the islands of magnetic material 6 come into contact with each other. At this time, the magnetic body 6 is magnetized by the magnetic flux lines 4. Regardless of whether the magnetic material 6 is a soft magnetic material or a hard magnetic material, a magnetic Coulomb attraction acts between the magnetic material 6 and the magnetic flux lines 4, and the magnetic flux lines 4 are trapped in the islands of the magnetic material 6. Since the magnetic material 6 is attached to the superconductor 1, it is not moved by an external magnetic field or Lorentzka. Therefore, this island-like magnetic body functions as a strong pinning center for the magnetic flux lines 4.
具体例として、超伝導体１としてＹＢＣＯ厚膜を、磁性
体６としてパーマロイ（ＮｉＦｅ合金）を用いた例を示
す。７７ＫでのＪｃは、ＹＢＣＯ膜単独では６００人／
ｃｍ２、ＹＢＣＯ膜の上にパーマロイを島状に堆積させ
た膜では、８００人／ｃｍ２となった．このＪｃの向上
から、磁性体６の堆積により超伝導体１のピン止め力が
強くなったことがわかる．
このように本発明による材料は従来の超伝導体と比較し
、磁気シールド材として必要な条件であるピン止め力の
強さの点で改善があった。As a specific example, an example will be shown in which a YBCO thick film is used as the superconductor 1 and permalloy (NiFe alloy) is used as the magnetic material 6. Jc at 77K is 600 people/year for YBCO membrane alone.
cm2, and for a film in which permalloy was deposited in an island shape on a YBCO film, it was 800 people/cm2. This improvement in Jc indicates that the pinning force of the superconductor 1 has become stronger due to the deposition of the magnetic material 6. As described above, the material according to the present invention has an improvement in the strength of pinning force, which is a necessary condition for a magnetic shield material, compared to conventional superconductors.
（発明の効果〉
以上説明したように、本発明による材料はピン止め力が
強いため、磁気シールド材として使用した場合、磁気シ
ールド効果が大きくかつ磁気ゆらぎが少なくなるという
利点がある。また、超伝導体内部の不均質点をピン止め
中心とするのではなく、超伝導体外部に隣接した磁性体
の磁化をピン止めとしているため、不均質点を形成する
ための作製法、加工法、および超伝導体の組織、組成構
造の最適化を図る必要がなく、またこれらの操作の結果
生ずる超伝導特性の劣化を回避できるという利点がある
。(Effects of the Invention) As explained above, the material according to the present invention has a strong pinning force, so when used as a magnetic shielding material, it has the advantage of having a large magnetic shielding effect and reducing magnetic fluctuations. Because the pinning is not centered on the heterogeneous point inside the conductor, but rather on the magnetization of the magnetic material adjacent to the outside of the superconductor, the manufacturing method, processing method, and There is an advantage that there is no need to optimize the structure and composition structure of the superconductor, and deterioration of the superconducting properties that occurs as a result of these operations can be avoided.
第１図は本発明の磁気シールド材に関する第１および第
２の実施例の断面図、第２図は本発明の前記第一および
第２の実施例の磁気シールド材の応用例の断面図、第３
図は磁性体の強磁性状態における磁化曲線、第４図は本
発明第１、第２の実施例でのビン止め機構を説明する図
、第５図は磁性微粒子の超常磁性状態における磁化曲線
、第６図は本発明の磁気シールド材に関する第３の実施
例の断面図、第７図は本発明の前記第３の実施例の磁気
シールド材の応用例の断面図、第８図、第９図は本発明
の第３の実施例でのピン止め機構を説明する図である。
１・
・超伝導体、２・
・磁性分子膜、磁性微粒
子分散膜、３・
．バッファ層、４・
・磁束線、
５・
・磁化領域、６・
・磁性体。FIG. 1 is a sectional view of the first and second embodiments of the magnetic shielding material of the present invention, and FIG. 2 is a sectional view of an application example of the magnetic shielding material of the first and second embodiments of the present invention. Third
The figure shows a magnetization curve of a magnetic substance in a ferromagnetic state, FIG. 4 is a diagram explaining the bottle locking mechanism in the first and second embodiments of the present invention, and FIG. 5 shows a magnetization curve of a magnetic fine particle in a superparamagnetic state. FIG. 6 is a cross-sectional view of a third embodiment of the magnetic shielding material of the present invention, FIG. 7 is a cross-sectional view of an application example of the magnetic shielding material of the third embodiment of the present invention, and FIGS. The figure is a diagram illustrating a pinning mechanism in a third embodiment of the present invention. 1. ・Superconductor, 2. ・Magnetic molecular film, magnetic fine particle dispersed film, 3. . Buffer layer, 4. Magnetic flux lines, 5. Magnetized region, 6. Magnetic material.
Claims (3)
有するバッファ層を介して強磁性体を形成したことを特
徴とする磁気シールド材。(1) A magnetic shielding material characterized in that a ferromagnetic material is formed directly on a superconductor surface or via a non-magnetic, non-superconducting buffer layer.
有するバッファ層を介して強磁性微粒子分散膜を形成し
たことを特徴とする磁気シールド材。(2) A magnetic shielding material characterized in that a ferromagnetic fine particle dispersed film is formed on a superconductor surface directly or via a non-magnetic, non-superconducting buffer layer.
有するバッファ層を介して強磁性体あるいは強磁性微粒
子分散材を島状に形成したことを特徴とする磁気シール
ド材。(3) A magnetic shielding material characterized in that a ferromagnetic material or a ferromagnetic fine particle dispersion material is formed in an island shape on a superconductor surface directly or via a non-magnetic, non-superconducting buffer layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30729189A JPH03166795A (en) | 1989-11-27 | 1989-11-27 | Magnetic shield material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30729189A JPH03166795A (en) | 1989-11-27 | 1989-11-27 | Magnetic shield material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03166795A true JPH03166795A (en) | 1991-07-18 |
Family
ID=17967366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30729189A Pending JPH03166795A (en) | 1989-11-27 | 1989-11-27 | Magnetic shield material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03166795A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06103846A (en) * | 1992-03-12 | 1994-04-15 | Chubu Electric Power Co Inc | Magnetic shield type bushing using composite superconductor |
-
1989
- 1989-11-27 JP JP30729189A patent/JPH03166795A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06103846A (en) * | 1992-03-12 | 1994-04-15 | Chubu Electric Power Co Inc | Magnetic shield type bushing using composite superconductor |
| JP2510373B2 (en) * | 1992-03-12 | 1996-06-26 | 中部電力株式会社 | Magnetic shield type bushing using composite superconductor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Wong et al. | Superconducting properties of V/Fe superlattices | |
| Sonin et al. | Spontaneous vortex phase in a superconducting weak ferromagnet | |
| Lu et al. | Shape-anisotropy-controlled magnetoresistive response in magnetic tunnel junctions | |
| Leksin et al. | Physical properties of the superconducting spin-valve Fe/Cu/Fe/In heterostructure | |
| Stamopoulos et al. | Effective ferromagnetic coupling between a superconductor and a ferromagnet in La Ca Mn O∕ Nb hybrids | |
| Ainslie et al. | Thickness dependence of trapped magnetic fields in machined bulk MgB 2 superconductors | |
| JPH03166795A (en) | Magnetic shield material | |
| Krebs et al. | Ferromagnetic resonance and spin anisotropy in iron oxide thin films and iron oxide/nickel oxide superlattices | |
| Meservey | Tunnelling in a magnetic field with spin-polarized electrons | |
| Rubinstein et al. | Properties of superconductor-ferromagnet bilayers: YBa 2 CuO 3-Fe and YBa 2 CuO 3-permalloy | |
| Banno et al. | Analytical formulae of coupling loss and hysteresis loss in HTS tape | |
| Gupta et al. | Magnetic properties and domain structure studies in dc triode‐sputtered permalloy/carbon multilayer films | |
| Matsushita et al. | Thickness dependence of pinning properties in Bi-2212 superconductor | |
| Wen et al. | Anomalous magnetization transition accompanying the irreversibility line in high-temperature superconductors | |
| Taniyama et al. | Ferromagnetism of Pd fine particles | |
| Jin et al. | Anisotropic upper critical fields of disordered Nb 0.53 Ti 0.47-Ge multilayers | |
| Viegas et al. | Correlation between giant magnetoresistance and magnetic interactions in a CoAg multilayered/granular system | |
| Iwasaki et al. | Magnetization peak around H∥ a axis in La 2− x Sr x CuO 4 single crystals with different anisotropy | |
| Knauf et al. | Wohlleben effect in small grains of Bi-based high-temperature superconductors: evidence for intrinsic nature of spontaneous currents | |
| Satariano et al. | Unconventional magnetic hysteresis of the Josephson supercurrent in magnetic Josephson Junctions | |
| US5113164A (en) | Superconductors with switchable magnetic domains | |
| Bottoni et al. | Effect of the coupling between Co and CoO in metal evaporated tapes | |
| Glowacki et al. | The effect of the time dependent angular distribution of the intergrain magnetic field on the transport critical current in Ag‐(Bi, Pb) 2Sr2Ca2Cu3O x tapes | |
| JPH03155174A (en) | Improving method for critical current density of superconducting material | |
| Itoh et al. | Magnetic shielding by superposition of hybrid ferromagnetic cylinder over a YBCO thick-film cylinder |