JPH0799387B2 - Driving method of ceramics superconducting magnetic sensor - Google Patents
Driving method of ceramics superconducting magnetic sensorInfo
- Publication number
- JPH0799387B2 JPH0799387B2 JP62193018A JP19301887A JPH0799387B2 JP H0799387 B2 JPH0799387 B2 JP H0799387B2 JP 62193018 A JP62193018 A JP 62193018A JP 19301887 A JP19301887 A JP 19301887A JP H0799387 B2 JPH0799387 B2 JP H0799387B2
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- Prior art keywords
- current
- magnetic sensor
- magnetic field
- driving
- superconducting
- Prior art date
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- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Description
【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は、発明者らが発明した新しい原理に基づく高感
度の超電導磁気センサの駆動方式に関するものであり、
更に詳細には、高精度かつ、信頼性、安定性をもつ磁界
測定を必要とする産業分野、医療分野の高感度な測定に
用いて好適な超電導磁気センサの駆動方式に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a driving system for a highly sensitive superconducting magnetic sensor based on a new principle invented by the inventors.
More specifically, the present invention relates to a drive system of a superconducting magnetic sensor which is suitable for use in highly sensitive measurement in industrial fields and medical fields that require highly accurate, reliable, and stable magnetic field measurement.
＜従来の技術及びその問題点＞ 従来、磁気検出のためには、半導体や磁性体を用いた磁
気抵抗効果素子が用いられているが、磁界検出感度は数
100ガウス程度であった。また、磁気抵抗効果素子の抵
抗増加は、ある領域で磁界の２乗に比例するので、磁界
の低い値に対しては抵抗増加は著しく小さい。<Prior art and its problems> Conventionally, a magnetoresistive effect element using a semiconductor or a magnetic body has been used for magnetic detection, but the magnetic field detection sensitivity is several.
It was about 100 gauss. Further, since the increase in resistance of the magnetoresistive effect element is proportional to the square of the magnetic field in a certain region, the increase in resistance is extremely small for low values of the magnetic field.
更に超電導体を用いたSQUID磁束センサがあるが、構造
が複雑な上、極低温を必要としていた。Furthermore, there is a SQUID magnetic flux sensor using a superconductor, but its structure is complicated and it requires cryogenic temperature.
上記した従来の磁気センサの問題点を解決するため、本
発明者等は先に特許願「超電導磁気検出素子」（昭和62
年７月29日出願）として第１図に示すようにセラミック
ス超電導体素子１に電流電極2,3及び電圧電極4,5を接触
させただけの極めて簡単な構造にて、第２図に示すよう
に印加磁界Ｈに対して敏感に出力電圧を発生するセラミ
ックス超電導磁気センサを提案した。しかし、その動作
特性を詳細に検討した所、ある種のセラミックス超電導
磁気センサは一定電流を流したままで低磁界の下で、そ
の強さを変化させると、第３図に示すようなヒステリシ
ス現象を示すことを見い出した。このヒステリシス現象
は微小磁界の検出にあたっては誤差を生じる。In order to solve the above-mentioned problems of the conventional magnetic sensor, the present inventors have previously made a patent application for "superconducting magnetic detection element" (Showa 62).
(Applied on July 29, 2002) As shown in FIG. 1, it has a very simple structure in which the current electrodes 2, 3 and the voltage electrodes 4, 5 are brought into contact with the ceramic superconductor element 1 as shown in FIG. Thus, we have proposed a ceramics superconducting magnetic sensor that produces an output voltage sensitively to an applied magnetic field H. However, when the operating characteristics were examined in detail, when a certain type of ceramics superconducting magnetic sensor changed its strength under a low magnetic field while a constant current was flowing, a hysteresis phenomenon as shown in FIG. 3 was observed. I found what to show. This hysteresis phenomenon causes an error in detecting a minute magnetic field.
本発明は、上記の点に鑑みて創案されたものであり、ヒ
ステリシス現象があっても安定な磁界検出を可能とする
セラミックス超電導磁気センサの駆動方式を提供するこ
とを目的としたものである。The present invention was made in view of the above points, and an object thereof is to provide a driving method of a ceramics superconducting magnetic sensor that enables stable magnetic field detection even if there is a hysteresis phenomenon.
＜問題点を解決するための手段及び作用＞ 上記の目的を達成するため、本発明のセラミックス超電
導磁気センサの駆動方式は、超電導体粒子が電気的に弱
く結合された弱結合を有するセラミック超電導体よりな
る磁気センサを駆動する方法であって、その駆動電流と
して、電流値が零の状態から電流が流れるようにした駆
動電流を用いるように構成している。<Means and Actions for Solving Problems> In order to achieve the above object, the driving method of the ceramics superconducting magnetic sensor of the present invention is a ceramics superconductor having weak coupling in which superconducting particles are electrically weakly coupled. A method of driving a magnetic sensor having the above-mentioned configuration, wherein the drive current used is a drive current that allows the current to flow from a state where the current value is zero.
超電導体粒子が電気的に弱く結合された弱結合を有する
セラミック超電導体を超電導状態を示す臨界温度以下の
温度に保ちながら超電導体に磁界をかけると、第２図に
示す様に磁界が０〜５エルステッド程度まで超電導状態
を維持し、超電導体の抵抗は零である。磁界が５エルス
テッド以上になると超電導状態が破れ、電気抵抗を示
す。このとき電気抵抗は印加磁界に対して、従来の磁気
抵抗効果素子に比べて急峻な立上り特性を示すことを本
発明者等は見出した。When a magnetic field is applied to the superconductor while maintaining the temperature below the critical temperature indicating the superconducting state, the ceramic superconductor in which the superconductor particles are electrically weakly coupled and has weak coupling causes a magnetic field of 0 to 0 as shown in FIG. The superconducting state is maintained up to about 5 Oersted, and the resistance of the superconductor is zero. When the magnetic field exceeds 5 Oersted, the superconducting state is broken and the electric resistance is exhibited. At this time, the present inventors have found that the electric resistance exhibits a steep rising characteristic with respect to the applied magnetic field as compared with the conventional magnetoresistive effect element.
セラミックス超電導体を用いた磁気センサの上記のよう
な特性は、発明者等は次のように理解している。The present inventors understand the above characteristics of the magnetic sensor using the ceramics superconductor as follows.
即ち、上記のような特性は、セラミックス焼結体が多く
の超電導体粒子より構成され、その粒子境界に極めて薄
い絶縁物が存在するか、あるいは粒子間の接触部分がポ
イント状になる等、いわゆる超電導体粒子が電気的に弱
く結合された超電導の弱結合の集合体とみなすことが出
来、弱磁界（臨界磁界）で超電導状態が破れる結果、生
じるものであり、換言すれば、セラミックス超電導体粒
子同志の接触界面のトンネル現象の結果、生じるものと
考えている。That is, the above-mentioned characteristics are so-called that the ceramics sintered body is composed of many superconducting particles, there is an extremely thin insulator at the particle boundary, or the contact portion between particles becomes a point shape. The superconducting particles can be regarded as a weakly coupled aggregate of superconducting particles that are weakly electrically coupled, and the result is that the superconducting state is broken in a weak magnetic field (critical magnetic field). In other words, ceramic superconducting particles. It is believed that this occurs as a result of the tunneling phenomenon at the contact interface between the two.
しかし上記した磁界に対する急峻な立上がり特性を示す
動作特性を詳細に検討した所第３図に示す様なヒステリ
シス現象を示し、このヒステリシスの程度は全体として
は極めて小さく、大きな磁界の検出に当っては、さほど
実用上問題とならないが、数十ガウス程度の微小磁界に
対して出力電圧に大きな誤差を発生することになる。However, a detailed examination of the above-mentioned operation characteristics exhibiting a steep rising characteristic with respect to the magnetic field shows a hysteresis phenomenon as shown in FIG. 3, and the degree of this hysteresis is extremely small as a whole, and it is not possible to detect a large magnetic field. Although not a serious problem in practical use, a large error will occur in the output voltage with respect to a minute magnetic field of several tens Gauss.
発明者らは、一度、該超電導体に流す素子電流を切り、
零としてから、電流を流せば、一定磁界に対しては常に
一定出力を検出することが出来ることを確認した。The inventors once cut off the device current flowing in the superconductor,
It was confirmed that a constant output can always be detected for a constant magnetic field by applying a current after setting it to zero.
＜実施例＞ 以下、図面を参照して本発明の一実施例を詳細に説明す
る。<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
第１図は本発明の駆動方式の適用されるセラミックス超
電導磁気センサの構成例を示す斜視図である。FIG. 1 is a perspective view showing a structural example of a ceramics superconducting magnetic sensor to which the driving system of the present invention is applied.
超電導素子１は、酸化イットリウムY2O3,炭酸バリウムB
aCO3,酸化銅CuOを1:2:3に秤量し、充分に分散混合した
微粒子を900℃,5時間空気中で仮焼成し、それを再び粉
砕，分散させ、プロブスカイト型酸化物超電導体の均一
な微粒子（１μｍφ以下）からなる粉体を作製し、次に
最適な形、例えば円状のペレットに加圧力1ton/cm2にて
加圧形成した後、空気中で1000℃,3時間保持し、200℃
まで５時間で降温させて厚み1mmの円状のペレットを作
製した。なお、本実施例においては、超電導セラミック
スとしてＹ−Ba−Cu−Ｏ系を例にして説明しているが、
本発明の適用されるセラミックス超電導磁気センサはこ
れに限定されることなく、例えばLa−Ba−Cu−Ｏ系,Y−
Sr−Ba−Cu−Ｏ系等のIII a族元素,II a族元素，銅（C
u）元素及び酸素（Ｏ）元素を構成元素とした超電導セ
ラミックスよりなる磁気センスでヒステリシス特性を有
するものに用いても同様に実施することが出来ることは
言うまでもない。The superconducting element 1 is composed of yttrium oxide Y 2 O 3 and barium carbonate B.
ACO 3 and copper oxide CuO were weighed 1: 2: 3, and the finely dispersed and mixed particles were calcined in air at 900 ° C for 5 hours, then pulverized and dispersed again to obtain a perovskite oxide superconductor. Of uniform fine particles (1 μmφ or less) are prepared, and then the pellets of optimal shape, for example, circular are formed under pressure with a pressure of 1 ton / cm 2 , and then 1000 ° C in air for 3 hours. Hold and 200 ℃
The temperature was lowered for 5 hours to prepare a circular pellet having a thickness of 1 mm. In the present embodiment, the Y-Ba-Cu-O system is taken as an example of the superconducting ceramics.
The ceramic superconducting magnetic sensor to which the present invention is applied is not limited to this, and may be, for example, a La-Ba-Cu-O system, Y- system.
Group IIIa elements such as Sr-Ba-Cu-O system, IIa group elements, copper (C
It goes without saying that the same can be applied to the case where the magnetic sense is made of superconducting ceramics having u) element and oxygen (O) element as constituent elements and has a hysteresis characteristic.
次に、上記のようにして作製した材料より、薄い長方形
に切り出してセラミックス超電導体素子１を作製した。
上記の例における超電導体素子１は（Y1−Ba2−Cu3）O6
の組成になっており、超電導の弱結合状態の破られる磁
界（臨界磁界）は約５エルステッドである。Next, a ceramic superconducting element 1 was produced by cutting the material produced as described above into a thin rectangle.
The superconductor element 1 in the above example is (Y 1 -Ba 2 -Cu 3 ) O 6
And the magnetic field (critical magnetic field) in which the superconducting weakly coupled state is broken is about 5 oersteds.
この素子１の両端及びその内側近傍にそれぞれオーム性
の電流電極2,3及び電圧電極4,5をチタン（Ti）の蒸着膜
及び銀ペーストを用いて形成し、電流電極2,3を定電流
源６に接続すると共に、電圧電極4,5を電圧検出器７に
接続した。The ohmic current electrodes 2 and 3 and the voltage electrodes 4 and 5 are formed at both ends of the element 1 and in the vicinity thereof using a titanium (Ti) vapor deposition film and a silver paste, respectively, and the current electrodes 2 and 3 are made to have a constant current. In addition to being connected to the source 6, the voltage electrodes 4, 5 were connected to the voltage detector 7.
上記のような構成において、定電流源６より一定電流を
素子１に流したままで、磁界Ｈを減少させた場合には、
セラミックスの結晶粒界に存在する弱結合の超電導性が
破れたままに保持される結果、ヒステリシスが現われる
と考えられる。In the above configuration, when the magnetic field H is reduced while a constant current is being supplied to the element 1 from the constant current source 6,
Hysteresis is considered to appear as a result of the weakly-coupling superconductivity existing at the grain boundaries of ceramics being maintained.
したがって、このような第１図に示される素子１に第４
図（ａ）のように一度零から流れ始まる電流や第４図
（ｂ）のようなパルス電流、第４図（ｃ）のような交番
電流あるいは第４図（ｄ）のような鋸歯状電流等、常に
一度電流値が零に戻る性質を持つ電流すなわち、常に電
流零の状態からある電流値の電流が流れる様な素子の駆
動方式を用いれば、磁界の変化に対する出力電圧のヒス
テリシスは全く現われず第５図のように安定で信頼性の
高い磁界検出が得られる。なお、第４図（ｃ）または
（ｄ）に示すような波形の電流を供給して磁界を測定す
る場合には、増加する電流値のピーク値等の所定の値の
タイミングで磁界のサンプリング測定を行なう必要があ
る。Therefore, the element 1 shown in FIG.
A current that once starts to flow from zero as shown in FIG. 4A, a pulse current as shown in FIG. 4B, an alternating current as shown in FIG. 4C, or a sawtooth current as shown in FIG. 4D. For example, if a drive method of an element in which the current value always returns to zero once, that is, the current of a certain current value always flows from the zero current state, the hysteresis of the output voltage with respect to the change of the magnetic field appears at all. As shown in FIG. 5, stable and highly reliable magnetic field detection can be obtained. When supplying a current having a waveform as shown in FIG. 4 (c) or (d) to measure the magnetic field, sampling measurement of the magnetic field is performed at a timing of a predetermined value such as a peak value of the increasing current value. Need to do.
以上のようにセラミックス超電導体を用いた磁気センサ
において、駆動電流として常に電流零の状態からある数
値の電流が流れるような駆動電流を該磁気センサに印加
することにより、極めて安定に、信頼性高く磁界の強さ
の検出を行うことが出来る。As described above, in a magnetic sensor using a ceramics superconductor, by applying a driving current to the magnetic sensor such that a current of a certain value always flows as a driving current, it is extremely stable and highly reliable. It is possible to detect the strength of the magnetic field.
＜発明の効果＞ 以上の説明の通り本発明は、セラミックス超電導素子の
磁界に対する電気抵抗の変化が大きく、超電導体特有の
ヒステリシス現象を解消し、極めて安定に、信頼性高
く、磁界の強さの検出を行うことのできる駆動方式であ
り、高度の精度を必要とする医療診断用の磁気測定ある
いはFA等高い精度の磁気計測技術に適用して効果は絶大
なものであり、産業上に大きく貢献するものである。<Effects of the Invention> As described above, according to the present invention, the electric resistance of the ceramic superconducting element is largely changed with respect to the magnetic field, the hysteresis phenomenon peculiar to the superconductor is eliminated, and the stability and the reliability of the magnetic field are extremely high. It is a drive system that can perform detection, and its effect is tremendous when applied to highly accurate magnetic measurement technology such as magnetic measurement for medical diagnosis or FA that requires high accuracy, and it makes a great contribution to the industry. To do.
第１図は本発明の適用されるセラミックス超電導磁気セ
ンサの素子構造例を示す図、第２図は本センサの磁界に
対する抵抗変化の特性を示す図、第３図は本センサの低
磁界付近のヒステリシス特性を示す図、第４図（ａ）乃
至（ｄ）はそれぞれ本発明の駆動方式を説明するための
図であり、超電導磁気センサに流す素子電流波形を示す
図、第５図は本発明の駆動方式によりヒステリシスが解
消された特性を示す図である。 １……セラミックス超電導磁気センサ、2,3……電流電
極、4,5……電圧電源、６……定電流源、７……電圧検
出器。FIG. 1 is a diagram showing an element structure example of a ceramics superconducting magnetic sensor to which the present invention is applied, FIG. 2 is a diagram showing characteristics of resistance change with respect to a magnetic field of the present sensor, and FIG. FIGS. 4 (a) to 4 (d) are diagrams for explaining the driving method of the present invention, respectively, showing a hysteresis characteristic, and FIGS. 5 (a) and 5 (b) are diagrams showing element current waveforms to be passed through the superconducting magnetic sensor. It is a figure which shows the characteristic by which the hysteresis was eliminated by the drive system of FIG. 1 ... Ceramic superconducting magnetic sensor, 2, 3 ... Current electrode, 4,5 ... Voltage source, 6 ... Constant current source, 7 ... Voltage detector.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭59−17175（ＪＰ，Ａ) 特開 昭55−56706（ＪＰ，Ａ) 特公 昭46−24631（ＪＰ，Ｂ１) Ｃ．Ｗ．Ｃｈｕ，ｅｔ ａｌ．：Ｐｈｙ ｓ．Ｒｅｖ．Ｌｅｔｔ．Ｖｏｌ．58 Ｎ ｏ．４，26 Ｊａｎｕａｒｙ 1987 Ｐ Ｐ．405−407 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-59-17175 (JP, A) JP-A-55-56706 (JP, A) JP-B-46-24631 (JP, B1) C.I. W. Chu, et al. : Phy s. Rev. Lett. Vol. 58 No. 4,26 January 1987 P.P. 405-407
Claims (4)
結合を有するセラミック超電導体よりなる磁気センサを
駆動する方法であって、 その駆動電流として、電流値が零の状態から電流が流れ
るようにした駆動電流を用いることを特徴とするセラミ
ックス超電導磁気センサの駆動方式。1. A method for driving a magnetic sensor comprising a ceramic superconductor having weak coupling, in which superconductor particles are electrically weakly coupled, wherein a current flows from a state where a current value is zero as a driving current. A driving method for a ceramics superconducting magnetic sensor, characterized by using the driving current as described above.
とする特許請求の範囲第１項記載のセラミックス超電導
磁気センサの駆動方式。2. The driving method for a ceramics superconducting magnetic sensor according to claim 1, wherein the driving current is an alternating current.
徴とする特許請求の範囲第１項記載のセラミックス超電
導磁気センサの駆動方式。3. The method for driving a ceramics superconducting magnetic sensor according to claim 1, wherein the drive current is a pulse current.
徴とする特許請求の範囲第１項記載のセラミックス超電
導磁気センサの駆動方式。4. The method for driving a ceramics superconducting magnetic sensor according to claim 1, wherein the drive current is a sawtooth current.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62193018A JPH0799387B2 (en) | 1987-08-01 | 1987-08-01 | Driving method of ceramics superconducting magnetic sensor |
| US07/226,067 US5011818A (en) | 1987-07-29 | 1988-07-29 | Sensing a magnetic field with a super conductive material that exhibits magneto resistive properties |
| DE88307044T DE3884514T2 (en) | 1987-07-29 | 1988-07-29 | Method and arrangement for detecting a magnetic field using the magnetoresistance properties of a superconducting material. |
| EP88307044A EP0301902B1 (en) | 1987-07-29 | 1988-07-29 | Method and device for sensing a magnetic field with use of a magneto-resistive property of a superconductive material |
| AT88307044T ATE95316T1 (en) | 1987-07-29 | 1988-07-29 | METHOD AND ARRANGEMENT FOR DETECTING A MAGNETIC FIELD BY MEANS OF MAGNETORESISTANCE PROPERTIES OF A SUPERCONDUCTING MATERIAL. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62193018A JPH0799387B2 (en) | 1987-08-01 | 1987-08-01 | Driving method of ceramics superconducting magnetic sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01145589A JPH01145589A (en) | 1989-06-07 |
| JPH0799387B2 true JPH0799387B2 (en) | 1995-10-25 |
Family
ID=16300809
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62193018A Expired - Lifetime JPH0799387B2 (en) | 1987-07-29 | 1987-08-01 | Driving method of ceramics superconducting magnetic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0799387B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5556706A (en) * | 1978-10-23 | 1980-04-25 | Denki Onkyo Co Ltd | Driving circuit for magnetic resistance element |
| JPS5917175A (en) * | 1982-07-20 | 1984-01-28 | Aisin Seiki Co Ltd | Detecting element of magnetic field for extremely low temperature |
-
1987
- 1987-08-01 JP JP62193018A patent/JPH0799387B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| Ｃ．Ｗ．Ｃｈｕ，ｅｔａｌ．：Ｐｈｙｓ．Ｒｅｖ．Ｌｅｔｔ．Ｖｏｌ．５８Ｎｏ．４，２６Ｊａｎｕａｒｙ１９８７ＰＰ．４０５−４０７ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01145589A (en) | 1989-06-07 |
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