JPH0312092A - Magnetic storage element - Google Patents

Magnetic storage element

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Publication number
JPH0312092A
JPH0312092A JP1144895A JP14489589A JPH0312092A JP H0312092 A JPH0312092 A JP H0312092A JP 1144895 A JP1144895 A JP 1144895A JP 14489589 A JP14489589 A JP 14489589A JP H0312092 A JPH0312092 A JP H0312092A
Authority
JP
Japan
Prior art keywords
pattern
magnetic
film pattern
magnetization
superconductor
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.)
Granted
Application number
JP1144895A
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Japanese (ja)
Other versions
JP2797443B2 (en
Inventor
Yasuharu Hidaka
桧高 靖治
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
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Publication of JPH0312092A publication Critical patent/JPH0312092A/en
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Publication of JP2797443B2 publication Critical patent/JP2797443B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To improve stability and to reduce power consumption by superimposing a high coercive force ferromagnetic film pattern and a low coercive force ferromagnetic film pattern by interposing a superconductor layer. CONSTITUTION:A first conductor wire 1 is arranged on a substrate via an insulating layer. A superconductor pattern 6 having micro-Josephson junction for information readout, a second magnetic film pattern 3, and the thin film 8 of a superconductor having a critical magnetic field with the same degree as that of the superconductor used in a lead wire are provided via the insulating layer 5, and a first magnetic film pattern 4 is arranged. A second conductor wire 2 is arranged so as to cross with the position 1 of the magnetic film pattern via an insulating layer 9. The write of information is performed by supplying a pulse shape current to the conductor wires 1 and 2. Readout is performed by using a conductor pattern for information readout, a lead wire 7, and the conductor wire 2. Thus, no magnetic flux of the pattern 3 is inputted to the pattern 4 according to magnetic inversion, and instead of that, it is inputted to the pattern 6, and breaks the superconducting state of the pattern 6, then, it goes to a stationary conducting state, and a detection ratio can be heightened by utilizing the output of a voltage and detecting it with the conductor pattern for information readout.

Description

【発明の詳細な説明】 (産業上の利用分野) 本発明は不揮発性の高密度固体磁気記憶素子に関する。[Detailed description of the invention] (Industrial application field) The present invention relates to nonvolatile high-density solid-state magnetic storage elements.

(従来の技術) 固体磁気メモリは機械駆動部がなく、かつ不揮発性のメ
モリであるため、高い信頼性をもっている。固体磁気メ
モリを大きく分類すると、ランダムアクセス型メモリと
、シリアルアクセス型メモリとになる。コアメモリは前
者の代表的なものであり、バブルメモリは後者の代表的
なものである。高密度記憶素子を目指すとき、ランダム
アクセス型は各ビット毎に検出器を備えている必要があ
るため、セルサイズを小さくしていくことに限界がある
。他方、シリアルアクセス型は、高密度化は比較的容易
であるが、高密度化に伴うアクセス時間の増加が大きな
問題になっている。さらに、バブルメモリのように情報
担体であるバブルの移動を必要とする素子では、移動に
伴い情報保持の安定性が悪くなる欠点を持っている。こ
のような状況を考えると、不揮発性固体磁気メモリとし
ては、ランダムアクセス型のメモリで検出器を開発し、
高密度化を実現するのが望ましい。
(Prior Art) Solid-state magnetic memory has high reliability because it does not have a mechanical drive unit and is a nonvolatile memory. Solid-state magnetic memory can be broadly classified into random access type memory and serial access type memory. Core memory is a typical example of the former, and bubble memory is a typical example of the latter. When aiming for high-density storage elements, the random access type requires a detector for each bit, which limits the ability to reduce the cell size. On the other hand, in the serial access type, it is relatively easy to increase the density, but the increase in access time accompanying the increase in density is a major problem. Furthermore, devices such as bubble memories that require the movement of bubbles, which are information carriers, have the disadvantage that the stability of information retention deteriorates as the bubbles move. Considering this situation, we have developed a detector using random access memory as a non-volatile solid-state magnetic memory.
It is desirable to achieve high density.

磁性体を用いたランダムアクセスメモリの基本動作を磁
性薄膜メモリを例に説明する。磁性薄膜としては、例え
ば磁歪定数λ二〇のソフト磁性材料である19%Fe−
81%Niの合金を用い、これを第9図に示すように、
基板上に円盤状に蒸着する。膜厚は1oooA程度であ
る。蒸着の際に磁界を与えておくことにより、膜面内に
一軸磁気異方性を付けておく。いまの場合、Y−軸方向
を磁化容易軸とするようにつける。
The basic operation of a random access memory using a magnetic material will be explained using a magnetic thin film memory as an example. As the magnetic thin film, for example, 19% Fe-, which is a soft magnetic material with a magnetostriction constant λ20, is used.
Using an 81% Ni alloy, as shown in Figure 9,
It is deposited in a disk shape on the substrate. The film thickness is about 1oooA. By applying a magnetic field during vapor deposition, uniaxial magnetic anisotropy is imparted within the film plane. In this case, it is attached so that the Y-axis direction is the axis of easy magnetization.

磁化の反転に際しては、容易軸に平行に磁化の向きと逆
向きの磁界HYをX。−線により与える際に、それと同
時に直角方向に磁界HxIYo−に線によって与え、磁
壁移動による磁化反転を阻止し、磁気モーメントの一斉
回転モードを利用してIonsオーダの短い時間で磁化
反転させている。これに対して、HYのみが加えられて
いる磁性膜パターン12では、磁壁移動による磁化反転
を生じようとするが、反転時間が長くかかるため、実際
に書き込みに使っている短い時間幅のHYでは反転は起
こらない。つまり、X一方向の導体線とY一方向の導体
線によって同時に磁界を与えたときのみ、磁性膜パター
ン12の磁化反転が12′に示すように生じる。磁界H
x、HYは蒸着膜に近接させて縦横に配置した導体線に
電流を与えることによって作り出す。しかし、この素子
は磁性体膜パターンの磁化が隣接するセルとの相互作用
のため、次第にもとの向きに戻ったりして情報の記憶の
安定性がよくないこと、また磁性体パターンを微小化し
ていくと検出出力が小さくなり、情報の読み出しが難し
くなってしまうなどの難点を有していた。
When reversing magnetization, a magnetic field HY in the opposite direction to the magnetization direction is applied parallel to the easy axis. - At the same time, the magnetic field HxIYo- is applied by a line in the perpendicular direction to prevent magnetization reversal due to domain wall movement, and the magnetization is reversed in a short time on the order of Ions by using the simultaneous rotation mode of the magnetic moment. . On the other hand, in the magnetic film pattern 12 to which only HY is added, magnetization reversal occurs due to domain wall movement, but since the reversal time is long, the short time width of HY actually used for writing is No reversal occurs. That is, only when a magnetic field is simultaneously applied by the conductor wire in the X direction and the conductor wire in the Y direction, the magnetization reversal of the magnetic film pattern 12 occurs as shown at 12'. magnetic field H
x and HY are created by applying current to conductor wires arranged vertically and horizontally close to the deposited film. However, with this element, the magnetization of the magnetic film pattern gradually returns to its original orientation due to interaction with adjacent cells, resulting in poor stability of information storage. As time goes on, the detection output becomes smaller, making it difficult to read out information.

(発明が解決しようとする問題点) 本発明はこれらの問題点を解決し、高密度記憶を実現す
るため、1960年代にすでに考案されていた二重膜構
造磁性体膜パターンを使った素子に改良を加えて高密度
大容量記憶を可能にする素子を提案している。従来は、
二重膜構造磁性体膜の間にセンス線を挟んだ構造で、磁
性体膜パターンの磁化反転に伴う磁束変化から生じる誘
導起電力を検知していた。この方法はセルサイズの微小
化に適していなかった。また、本発明者の提案になる磁
気抵抗記憶素子(特願昭63−42089、特願昭63
−61493)では、情報記憶用磁性体膜パターンと対
にして配置している読み出し用の磁性体膜パターンを隣
同士圧いに結合して記憶情報の読み出し線に使っている
。しかし、この方法では、パターンを微小化していくと
、パターン膜厚も薄くなり、書き込み線、読み出しく検
出)線の電気抵抗が急激に増加し、消費電力が大きくな
るとか、検出出力が小さくなる欠点があり、高密度記憶
素子にはなりにくい点があった。
(Problems to be Solved by the Invention) In order to solve these problems and realize high-density storage, the present invention has developed an element using a double-layer magnetic film pattern, which had already been devised in the 1960s. We are proposing an improved device that enables high-density, large-capacity storage. conventionally,
The double-layer structure has a sense line sandwiched between magnetic films to detect the induced electromotive force generated from changes in magnetic flux caused by magnetization reversal in the magnetic film pattern. This method was not suitable for miniaturizing the cell size. In addition, the magnetoresistive memory element proposed by the present inventor (Japanese Patent Application No. 63-42089,
-61493), magnetic film patterns for reading arranged in pairs with magnetic film patterns for information storage are coupled adjacently to each other and used as read lines for stored information. However, with this method, as the pattern becomes smaller, the pattern film thickness also becomes thinner, and the electrical resistance of the write line, readout (detection) line increases rapidly, and power consumption increases and the detection output decreases. It has some drawbacks and is difficult to use as a high-density memory element.

本発明では、従来方法で問題になったセルサイズの微小
化に伴う読み出し線の電気抵抗の上昇を抑え、かつ情報
記憶膜パターンの減磁磁界を小さくした高密度、大容量
磁気記憶素子を可能にするセル構造を提示している。
The present invention enables a high-density, large-capacity magnetic memory element that suppresses the increase in electrical resistance of the readout line due to miniaturization of cell size, which was a problem with conventional methods, and reduces the demagnetizing magnetic field of the information storage film pattern. It presents a cell structure for

(問題点を解決するための手段) 本発明では、最近注目されてきている酸化物超伝導体を
利用した記憶情報の読み出し方法を採用して、従来の素
子と違って、磁性膜パターンには直接電流を流さない構
造のセル構造を提案している。新しい構造では、1)書
き込んだ情報の安定化と、2)情報の効率よい検出を、
高保磁力強磁性体膜パターンと低保磁力強磁性体膜パタ
ーン、もしくは膜面内に大きな一軸性の磁気異方性を有
する磁性体膜パターンと小さな一軸性の磁気異方性を有
する磁性体膜パターンを反磁性体である超伝導体層を介
して重ねた膜構造と透磁率が負である酸化物超伝導体パ
ターンとを組合せた構造を取り入れて、素子構造を単純
化し動作の安定性向上および消費電力の低減を図った高
密度固体磁気記憶素子を提示する。従来の素子において
も、セルサイズの微小化のため、読み出しに電磁誘導電
圧に代って、磁気抵抗効果を使っていた。磁気抵抗効果
が大きい材料は強磁性体膜か、半導体膜かに限られてい
た。半導体は電気抵抗がもともと大きいので微細化に際
しては、選択の対象にならなかった。
(Means for Solving the Problems) The present invention adopts a method for reading out stored information using oxide superconductors, which has been attracting attention recently, and unlike conventional elements, the magnetic film pattern is We are proposing a cell structure that does not allow direct current flow. The new structure allows for 1) stabilization of written information and 2) efficient detection of information.
High coercive force ferromagnetic film pattern and low coercive force ferromagnetic film pattern, or magnetic film pattern with large uniaxial magnetic anisotropy in the film plane and magnetic film with small uniaxial magnetic anisotropy Incorporating a structure that combines a film structure in which the pattern is layered with a diamagnetic superconductor layer and an oxide superconductor pattern with negative magnetic permeability to simplify the device structure and improve operational stability. We also present a high-density solid-state magnetic memory element with reduced power consumption. Conventional devices also use magnetoresistive effect instead of electromagnetic induction voltage for readout in order to miniaturize the cell size. Materials with a large magnetoresistive effect were limited to ferromagnetic films or semiconductor films. Semiconductors have inherently high electrical resistance, so they were not an option for miniaturization.

必然的に前者を使うようになった。使い方としては、透
磁率が大きいので読み出し用パターンとしての役割の他
に、情報記憶膜パターンの減磁磁界を小さくする役割も
担うようにした構造が採用されていた。しかし、この構
造では、セルを微小化していくとき線幅とともに膜厚も
それに伴って小さくして、磁化を膜面内に抑え込んだ状
態を保ち、検出効率の維持を図ってきた。このため電気
抵抗の上昇が原因で微小化に限界があった。
Out of necessity, I ended up using the former. In terms of usage, a structure was adopted in which, because of its high magnetic permeability, in addition to serving as a readout pattern, it also played the role of reducing the demagnetizing magnetic field of the information storage film pattern. However, in this structure, as the cell is miniaturized, the line width and film thickness are reduced accordingly to keep the magnetization suppressed within the film plane and maintain detection efficiency. For this reason, there was a limit to miniaturization due to the increase in electrical resistance.

これに引き替え、最近注目されている酸化物超伝導体を
電気抵抗が零の状態、つまり超伝導状態で使用すると透
磁率が負である。また、膜厚が500人程度になっても
超伝導には問題がない。読み出し用超伝導体膜パターン
では、磁界に応答して超伝導体膜が常伝導状態に変化す
るようにマイクロジョセフソン結合をもつ構造にしてお
く。膜面内の一軸性磁気異方性、または保磁力の少なく
ともいずれかが互いに異なる2つの磁性体膜を酸化物超
伝導体層で形成した交換相互作用分離層を介して重ねて
構成した3層構造膜をパターン化し、その外側に上述の
情報読み出し用超伝導体膜パターンをつけ、その上下に
該パターンの位置で互いに交差する第1、第2の超伝導
体線を備え、かつ3層構造パターンの外側の超伝導体膜
パターンには電流印加用のリード線を取り付けである磁
気記憶素子である。このようにして、情報の安定性、動
作の安定性向上、動作時間の短縮を図った高密度固体磁
気記憶素子を提供する。
In contrast, when oxide superconductors, which have been attracting attention recently, are used in a state where the electrical resistance is zero, that is, in a superconducting state, the magnetic permeability is negative. Moreover, there is no problem with superconductivity even if the film thickness is about 500 people. The readout superconductor film pattern has a structure with micro-Josephson coupling so that the superconductor film changes to a normal conduction state in response to a magnetic field. A three-layer structure in which two magnetic films differing in at least either in-plane uniaxial magnetic anisotropy or coercive force are stacked with an exchange interaction separation layer formed of an oxide superconductor layer interposed therebetween. The structural film is patterned, the above-mentioned superconductor film pattern for information reading is attached to the outside thereof, and first and second superconductor lines are provided above and below the pattern and intersect with each other at the position of the pattern, and the structure has a three-layer structure. A lead wire for applying current is attached to the superconductor film pattern outside the pattern, which is a magnetic memory element. In this way, a high-density solid-state magnetic memory element with improved information stability, improved operational stability, and reduced operating time is provided.

(実施例1) 第1図にはこの記憶素子に用いるユニットセルの構造の
例を示す。
(Example 1) FIG. 1 shows an example of the structure of a unit cell used in this memory element.

まず、基板(通常Siウェハ)上に絶縁層を介して、X
−軸方向に伸びた第1の導体線1を配置する。その上に
絶縁層5を介して、情報読み出し用のマイクロジョセフ
ソン接合をもつ超伝導体パターン6を配置し、その上に
第2の磁性体膜パターン3を配置し、その上にリード線
に使う超伝導体と同程度の臨界磁界を有する超伝導体(
非磁性体)の薄層8をおき、その上に第1の磁性体膜パ
ターン4を配置する。その上に絶縁層9を介して第2の
導体線2を磁性体膜パターンの位置で1と交わるように
配置する。情報の書き込みは導体線1.2にパルス状電
流を与えて行なう。読み出しは情報読み出し用導体パタ
ーンとそのリード7と導体線2を使って行なう。こうす
ることによって、情報読み出し用の磁性体膜パターン4
の磁化反転に伴って3の磁束が4に入らなくなり、代っ
て6に入り、6の超伝導状態を破って常伝導状態になり
、電圧が出ることを利用して情報読み出し用導体パター
ンで検知することになり、検出効率を高く保てる。
First, X
- arranging a first conductor wire 1 extending in the axial direction; A superconductor pattern 6 having a micro-Josephson junction for information reading is placed on top of that via an insulating layer 5, a second magnetic film pattern 3 is placed on top of that, and a lead wire is placed on top of that. A superconductor with a critical magnetic field comparable to that of the superconductor used (
A thin layer 8 of a non-magnetic material is placed, and a first magnetic film pattern 4 is placed thereon. A second conductor wire 2 is placed thereon with an insulating layer 9 in between so as to intersect with wire 1 at the position of the magnetic film pattern. Information is written by applying a pulsed current to the conductor wire 1.2. Reading is performed using the information reading conductor pattern, its leads 7, and the conductor wire 2. By doing this, the magnetic film pattern 4 for reading information is
With the magnetization reversal of , the magnetic flux of 3 no longer enters 4, and instead enters 6, breaking the superconducting state of 6 and becoming a normal conductive state, and using the fact that a voltage is generated, it can be used as a conductive pattern for information reading. The detection efficiency can be kept high.

本発明の特徴は情報読み出し用導体パターンにマイクロ
ジョセフソン結合をもつ酸化物超伝導体膜パターンを利
用することにより、情報安定化のため採用されていた磁
性体膜の二重膜構造による記憶情報の安定化を損なうこ
となく、安定した記憶情報読み出しを可能にし、かつ素
子の動作の安定性向上、動作時間の短縮を図っている点
と二重膜構造をなす2つの磁性体膜パターン間の超伝導
体薄膜8の膜厚を任意に制御できるようにした点にある
The feature of the present invention is that by using an oxide superconductor film pattern with micro-Josephson bonds in the conductor pattern for information reading, the storage information is created by the double film structure of the magnetic film, which was adopted for information stabilization. It enables stable reading of stored information without compromising the stability of the device, improves the stability of device operation, and shortens operation time. The point is that the thickness of the superconductor thin film 8 can be controlled arbitrarily.

本素子では、膜面内に大きい一軸磁気異方性をもつか、
高い保磁力をもつかの少なくともいずれかを満たす強磁
性体膜パターン3と膜面内に小さい一軸磁気異方性をも
つか、低い保磁力をもつかの少なくともいずれかを満た
す強磁性体膜パターン4とを組合せた二重膜構造パター
ンにおいて、情報は前者3に書き込み、記憶する。後者
のパターン4は書き込んだ情報の読み取りおよび書き込
まれた情報の安定保持に使う。また、ここで用いている
情報読み出し用超伝導体膜パターン6は通常は透磁率が
負あり、磁束の通路にはならないが、マイクロジョセフ
ソン接合をもっているので、磁界を印加すると磁束を通
すようになって、常伝導状態に遷移して電気抵抗を示す
。したがって、磁界が加わっていない状態では上下の磁
性体膜パターンとはほとんど磁気的に結合していない状
態で保たれる特徴をもっている。第1図に示すユニット
セルをマトリックス状に配列したのが第2図である。第
2図にAで示す点線で囲まれた部分がユニットセルであ
る。
This device has large uniaxial magnetic anisotropy within the film plane,
A ferromagnetic film pattern 3 that satisfies at least one of a high coercive force and a ferromagnetic film pattern that satisfies at least one of a small uniaxial magnetic anisotropy in the film plane and a low coercive force. In the double membrane structure pattern combining the former 3, information is written and stored in the former 3. The latter pattern 4 is used for reading written information and stably maintaining written information. In addition, the information reading superconductor film pattern 6 used here normally has negative magnetic permeability and does not serve as a path for magnetic flux, but since it has a micro-Josephson junction, it can pass magnetic flux when a magnetic field is applied. As a result, it transitions to a normal conduction state and exhibits electrical resistance. Therefore, when no magnetic field is applied, it has the characteristic that it is maintained in a state where it is almost not magnetically coupled to the upper and lower magnetic film patterns. FIG. 2 shows the unit cells shown in FIG. 1 arranged in a matrix. The part surrounded by the dotted line indicated by A in FIG. 2 is the unit cell.

第3図にパターン6に使用できる超伝導体薄膜の電気抵
抗Rと外部印加磁界H,,,,との関係を示している。
FIG. 3 shows the relationship between the electrical resistance R of the superconductor thin film that can be used in pattern 6 and the externally applied magnetic field H, .

H,、、、> HcrItで超伝導状態が破れて電気抵
抗がでてくる。
H,,,,> At HcrIt, the superconducting state is broken and electrical resistance appears.

第4図には、磁化困難方向に磁界HTを加えていないと
きの磁性体膜パターン3.4の一斉磁化回転による反転
モードの磁化曲線3′、4′の例を示している。横軸は
磁化容易方向に加えた外部磁界HY、縦軸は磁束密度B
を表している。人、HK  はそれぞれパターン3.4
の面内の一軸異方性磁界である。−斉磁化回転による磁
化反転を起こすときの磁化容易方向(Y−軸方向)に加
える磁界の大きさHYが膜面内の一軸異方性磁界の大き
さに依存して異なっていることを示している。この反転
磁界の差を本発明では利用している。本発明の素子に使
用する材料は導体としては、金、アルミなどが、超伝導
体としては、pb系、Nb系、またはBa−Y−Cu−
0系、B1−8r−Ca−Cu−0系、Tl−Ba−C
a−Cu−0系などのセラミックス、また絶縁体として
はSiO2などが使用できる。また磁性体膜には、広い
範囲の材料から選んだ適当なものが使用できる。薄膜作
成技術には公知の技術が利用できる。前記セラミックス
はスパッタリングやレーザ蒸着法を用いる事ができ、ま
た、エツチングは例えばドライエツチングが考えられる
FIG. 4 shows an example of magnetization curves 3' and 4' in reversal mode due to simultaneous magnetization rotation of the magnetic film pattern 3.4 when no magnetic field HT is applied in the direction of difficult magnetization. The horizontal axis is the external magnetic field HY applied in the direction of easy magnetization, and the vertical axis is the magnetic flux density B.
represents. People and HK each have a pattern of 3.4.
is the uniaxial anisotropic magnetic field in the plane of - Shows that the magnitude of the magnetic field HY applied in the direction of easy magnetization (Y-axis direction) when magnetization reversal occurs due to simultaneous magnetization rotation differs depending on the magnitude of the uniaxial anisotropic magnetic field in the film plane. ing. This difference in switching magnetic fields is utilized in the present invention. The material used for the element of the present invention is gold, aluminum, etc. as a conductor, and pb-based, Nb-based, or Ba-Y-Cu- as a superconductor.
0 series, B1-8r-Ca-Cu-0 series, Tl-Ba-C
Ceramics such as a-Cu-0 series, SiO2, etc. can be used as the insulator. Furthermore, suitable materials selected from a wide range of materials can be used for the magnetic film. Known techniques can be used for forming the thin film. The ceramic can be formed by sputtering or laser evaporation, and the etching can be, for example, dry etching.

情報の書き込みを説明する。初期状態として、情報記憶
に用いる強磁性体膜パターン3の磁化の向きを予め定め
られた向き(例えば、Y軸方向、負の向き)に飽和させ
、“0″を定義しておく、第5図(a)〜(d)はユニ
ットセルの断面図である。第5図(a)は紙面法線とX
−軸に平行な導体線1の中心線を含む面で切ったときの
セルの断面図である。磁化の向きは第5図(a)に10
で示すY−軸方向に沿った向きを正の向きとする。書き
込み動作は次のようにする。X−軸方向に走っている導
体線1およびY−軸方向に走っている導体線2にパルス
電流を与えて、各位置の磁性体膜パターン3の中で、導
体体線1と2とが交わる位置に存在している磁性体膜パ
ターン3の磁化の向き(Y−軸方向、負の向き)を第5
図(a)、(b)に10で示す正の向きへ反転させる。
Explain how to write information. As an initial state, the direction of magnetization of the ferromagnetic film pattern 3 used for information storage is saturated in a predetermined direction (for example, Y-axis direction, negative direction) and "0" is defined. Figures (a) to (d) are cross-sectional views of the unit cell. Figure 5(a) shows the paper surface normal and
- It is a sectional view of the cell when cut along a plane including the center line of the conductor wire 1 parallel to the axis. The direction of magnetization is shown in Figure 5(a).
The direction along the Y-axis direction shown by is defined as the positive direction. The write operation is performed as follows. By applying a pulse current to the conductor wire 1 running in the X-axis direction and the conductor wire 2 running in the Y-axis direction, the conductor wires 1 and 2 are connected in the magnetic film pattern 3 at each position. The direction of magnetization (Y-axis direction, negative direction) of the magnetic film pattern 3 existing at the intersecting position is the fifth
It is reversed in the positive direction as shown by 10 in Figures (a) and (b).

その様子を明瞭に示すため、第5図(b)にユニットセ
ルを紙面の法線とY−軸に平行な導体線2の中心線とを
含む面できったときのセル断面を示す。第5図(a)の
左側の側面から眺めた図である。以下(b)、(C)、
(d)の図面はすべてこの方向から眺めた図である。磁
性体膜パターン4の磁化の向きは保持状態では第5図(
b)に示すように、磁性体膜パターン3の磁化と結合し
て、磁性体膜パターン3の磁化の向きと逆向きに磁化さ
れているが、書き込み時には、第5図(c)に示すよう
に、反転してY−軸方向圧の向きに反転した3の磁化と
同じ向きになる。この状態から安定保持状態へできるだ
け短い時間で到達させるため、Y−軸方向に走っている
導体線2の電流をX−軸方向に走っている導体線1の電
流に比べて長時間保持しておく。そうすると、磁性体膜
パターン4の磁化は磁性体膜パターン3からの磁界とY
−軸方向の超伝導体線からの磁界との組み合せにより、
−斉磁化回転モードで反転し、第5図(d)に示す最終
状態(安定保持状態)に迅速に到達する。この回転速度
は2つの磁性体膜パターン間の相互作用が強いとそれだ
け速くなる。重要なことは情報記憶用の磁性体膜パター
ンの磁化状態が読み出し時に読み出し用の磁性体膜パタ
ーンの磁化状態を変化させたとき、それに引きずられて
変化することがないように、充分な大きさの磁気異方性
を与えておくことである。この磁気異方性の大きさによ
って、書き込み電流の最大値が決まる。情報保持状態で
は、強磁性体膜パターン4と強磁性体膜パターン3の間
に閉じた環流磁束線ができて減磁磁界を低減している。
In order to clearly illustrate this situation, FIG. 5(b) shows a cell cross section when the unit cell is formed on a plane including the normal to the plane of the paper and the center line of the conductor wire 2 parallel to the Y-axis. It is a view seen from the left side of FIG. 5(a). Below (b), (C),
All drawings in (d) are views viewed from this direction. The direction of magnetization of the magnetic film pattern 4 is as shown in Fig. 5 (
As shown in FIG. 5(b), the magnetization is combined with the magnetization of the magnetic film pattern 3 and is magnetized in the opposite direction to the magnetization direction of the magnetic film pattern 3. However, during writing, as shown in FIG. 5(c), , it becomes the same direction as the magnetization of 3, which is reversed and reversed to the direction of the Y-axis direction pressure. In order to reach the stable holding state from this state in the shortest possible time, the current in the conductor wire 2 running in the Y-axis direction is held for a longer time than the current in the conductor wire 1 running in the X-axis direction. put. Then, the magnetization of the magnetic film pattern 4 is caused by the magnetic field from the magnetic film pattern 3 and the Y
- In combination with the magnetic field from the axial superconductor wire,
- It is reversed in the simultaneous magnetization rotation mode and quickly reaches the final state (stable holding state) shown in FIG. 5(d). This rotation speed becomes faster as the interaction between the two magnetic film patterns becomes stronger. What is important is that the magnetization state of the magnetic film pattern for information storage is large enough so that it does not change as a result of changing the magnetization state of the magnetic film pattern for reading during reading. The objective is to provide magnetic anisotropy of . The maximum value of the write current is determined by the magnitude of this magnetic anisotropy. In the information retention state, closed circulation magnetic flux lines are formed between the ferromagnetic film pattern 4 and the ferromagnetic film pattern 3, reducing the demagnetizing magnetic field.

第6図(a)、(b)はそれぞれ情報′“0″または+
1111を示す安定化状態に対応している。なお、この
方法を用いたときの1ビツトのデータ書き込み時間は数
10nsのオーダである。なお、オーバライド時には、
情報書き込みに先立って、Y−軸方向導体線2の電流極
性は書き込み時と同じに保ったままで、X−軸方向導体
線に与える電流のみ、その極性を書き込み時と逆にした
リセットパルス磁界を用いるとか、書き込み情報が“′
0″か11111かに対応して極性が互いに逆の反転磁
界が情報記憶用の磁性体膜パターンに加わるよう°に外
部で制御するといった方法を使う。
Figures 6(a) and (b) indicate information ``0'' or +, respectively.
This corresponds to the stabilization state showing 1111. Note that the time required to write one bit of data using this method is on the order of several tens of ns. In addition, when overriding,
Prior to writing information, the current polarity of the Y-axis direction conductor wire 2 is kept the same as during writing, and only the current applied to the X-axis direction conductor wire is supplied with a reset pulse magnetic field whose polarity is reversed from that during writing. or if the written information is “′′
A method is used in which external control is performed so that inverted magnetic fields with opposite polarities corresponding to 0'' or 11111 are applied to the magnetic film pattern for information storage.

つぎに書き込んだ情報の読み出し方法の例を述べる。情
報を書き込んだ状態では、強磁性体膜パターン4と強磁
性体膜パターン3の磁化が互いに逆向きになっているた
め、磁束はそのほとんどが磁束抵抗が低い両磁性体膜パ
ターンを環流するルートをとっている。その結果、検出
用超伝導体パターン6の部分には磁束はほとんど通って
いなシ、)。
Next, an example of how to read the written information will be described. When information is written, the magnetization of the ferromagnetic film pattern 4 and the ferromagnetic film pattern 3 are in opposite directions, so most of the magnetic flux flows through the two magnetic film patterns, which have low magnetic flux resistance. is taking. As a result, almost no magnetic flux passes through the detection superconductor pattern 6).

この状態に対して、導体線7に定められた電流を与えた
とき、情報記憶用の磁性体膜パターン3では磁化の一斉
回転モードによる磁化反転が生じず、他方、読み出し用
の磁性体膜パターン4の磁化のみが一斉回転モードで反
転できるように、導体線2に与える電流を調整して、磁
化の向きを磁化容易方向(Y−軸)から傾けておく。つ
まり、Y−軸方向に走っている導体線を使って、磁界H
xを磁化困難方向(X−軸)に加えておく。第7図(a
)〜(C)に示しであるのが2つの磁性体膜パターンが
結合した状態である。第7図(b)、(d)にはそのと
きの2つの膜パターンそれぞれの一斉回転磁化反転曲線
を示している。実線で示した磁化反転曲線が縦軸に対し
て非対称になっているのは磁性体薄膜パターン3.4の
間の静磁結合効果を示している。第7図(a)は情報“
0”′に対応する状態、第7図(c)は“1′に対応す
る状態である。いま、1″を読み出すときには、検出用
超伝導体膜パターン6が常伝導に遷移し、“0°′を読
み出すときには常伝導に遷移しないことを示す。分かり
やすく説明するため、第7図を拡大した第8図(a)、
(b)を用いる。
In this state, when a predetermined current is applied to the conductor wire 7, magnetization reversal due to the simultaneous magnetization rotation mode does not occur in the magnetic film pattern 3 for information storage, and on the other hand, the magnetic film pattern for reading The current applied to the conductor wire 2 is adjusted to tilt the direction of magnetization from the easy magnetization direction (Y-axis) so that only the magnetization of the conductor wire 2 can be reversed in the simultaneous rotation mode. In other words, using conductor wires running in the Y-axis direction, the magnetic field H
x is added in the direction of difficult magnetization (X-axis). Figure 7 (a
) to (C) show the state in which two magnetic film patterns are combined. FIGS. 7(b) and 7(d) show simultaneous rotation magnetization reversal curves for each of the two film patterns at that time. The fact that the magnetization reversal curve shown by the solid line is asymmetrical with respect to the vertical axis indicates the magnetostatic coupling effect between the magnetic thin film patterns 3.4. Figure 7(a) shows the information “
The state corresponding to 0'' is shown in FIG. 7(c), and the state corresponding to 1' is shown in FIG. Now, when reading 1'', the detection superconductor film pattern 6 transitions to normal conduction, and when reading 0°', it indicates that it does not transition to normal conduction. For easy explanation, Figure 8(a) is an enlarged version of Figure 7.
Use (b).

読み出し時には、まず導体パターン2により、磁性体膜
パターンの磁化困難方向に磁界HTを加える。
At the time of reading, first, the conductor pattern 2 applies a magnetic field HT in the direction in which the magnetic film pattern is difficult to magnetize.

そうすると、磁性体膜パターン4の磁化が磁化容易方向
から困難方向へ回転する。この磁化回転により、第8図
(b)に実線で示す磁化反転曲線から一点鎖線で示す磁
化反転曲線のように、磁化−斉回転モードに必要な磁化
容易方向磁界の臨界値がHからH′へ低下する。磁化困
難方向へ磁界が加わっていないセルでは、この臨界値は
Hのままであるから、HTが加わっているセルと加わっ
ていないセルとで、磁化容易方向磁界の一斉磁化反転へ
の効き方を自動的に制御していることになる。この状態
に対して、導体線6によって、磁化容易方向へH’<H
<Hの範囲にある磁界Hを加える。そうすると、磁化を
困難方向に傾けておいた磁性体膜パターン4のみで、磁
化が一時的に反転する。つまり、磁性体膜パターン4の
磁化を磁化容易方向がら困難方向へ回転させることで、
磁化の一斉回転モードに必要な磁化容易方向磁界の臨界
値にH−H′だけ差をつけて、セルを特定している。
Then, the magnetization of the magnetic film pattern 4 rotates from the easy magnetization direction to the difficult magnetization direction. Due to this magnetization rotation, the critical value of the magnetic field in the easy direction of magnetization required for the magnetization-simultaneous rotation mode changes from H to H', from the magnetization reversal curve shown by the solid line to the magnetization reversal curve shown by the dashed line in FIG. 8(b). decreases to In cells to which no magnetic field is applied in the direction of hard magnetization, this critical value remains at H, so the effect of the magnetic field in the direction of easy magnetization on simultaneous magnetization reversal is determined between cells to which HT is applied and cells to which HT is not applied. It will be automatically controlled. In this state, the conductor wire 6 moves H'<H in the direction of easy magnetization.
Apply a magnetic field H in the range <H. Then, the magnetization is temporarily reversed only in the magnetic film pattern 4 whose magnetization is tilted in the difficult direction. In other words, by rotating the magnetization of the magnetic film pattern 4 from the easy magnetization direction to the difficult magnetization direction,
Cells are specified by making a difference of HH' from the critical value of the magnetic field in the direction of easy magnetization required for the simultaneous rotation mode of magnetization.

磁化反転が生じると、いままで磁性体膜パターン4に流
れていた磁性体膜パターン3を出た磁束が導体線7に接
続している超伝導体パターン6に入り、6を常伝導状態
に遷移させ、電気抵抗を生じる。導体線7には電流が与
えであるから、必然的に電圧を生じる。“0″の状態で
は、磁性体膜パターン4の磁化の向きは′1″のときと
逆向きであるため、“1″を読み出すために磁化容易方
向に加えた磁界では第6図(a)からも明らかなように
磁化容易方向に引寄せられ、磁化反転を生じないから、
導体パターン6へ磁束は入らない。つまり、電圧を生じ
ない。したがって、この方法により、記憶情報の“T′
、“011を弁別できる。読み出し後には、導体線6の
電流をまず切る。そうすると、強磁性体膜パターン4の
磁化は強磁性体膜パターン3がらの磁界とY−軸方向導
体線からの磁界との組合せで、−斉回転モードにより、
迅速に2つの磁性体膜パターンの安定結合状態に復帰す
る。
When magnetization reversal occurs, the magnetic flux leaving the magnetic film pattern 3 that has been flowing through the magnetic film pattern 4 enters the superconductor pattern 6 connected to the conductor wire 7, causing 6 to transition to a normal conduction state. and generates electrical resistance. Since a current is applied to the conductor wire 7, a voltage is inevitably generated. In the state of "0", the direction of magnetization of the magnetic film pattern 4 is opposite to that in the case of "1", so the magnetic field applied in the direction of easy magnetization to read out "1" is as shown in Fig. 6(a). As is clear from this, it is attracted to the direction of easy magnetization and does not cause magnetization reversal.
No magnetic flux enters the conductor pattern 6. In other words, no voltage is generated. Therefore, with this method, “T” of the stored information
, "011" can be discriminated. After reading, the current in the conductor wire 6 is first cut off. Then, the magnetization of the ferromagnetic film pattern 4 is divided by the magnetic field from the ferromagnetic film pattern 3 and the magnetic field from the Y-axis direction conductor wire. In combination with - simultaneous rotation mode,
The stable bonding state of the two magnetic film patterns is quickly restored.

なお、図中に点線で示す磁化反転曲線は磁性体膜パター
ン3と4とが互いに静磁結合していないときのものであ
る。磁性体膜パターン4には、磁性体膜パターン3との
静磁結合から生じる磁界Δのため、一方向磁気異方性が
つき、4の一斉回転磁化反転曲線は第8図に示すように
右にずれている。
Note that the magnetization reversal curve shown by the dotted line in the figure is a curve when the magnetic film patterns 3 and 4 are not magnetostatically coupled to each other. The magnetic film pattern 4 has unidirectional magnetic anisotropy due to the magnetic field Δ generated from the magnetostatic coupling with the magnetic film pattern 3, and the simultaneous rotation magnetization reversal curve of the pattern 4 has a right-hand direction as shown in FIG. It's off.

この読み出しの特徴は読み出し時の印加磁界を小さくし
て、情報を記憶している強磁性体膜パターン3の磁化状
態に影響を与えないようにしていること、読み出し線7
自身のセンス電流を磁化反転磁界発生に兼用したことで
、検出信号への印加磁界からの雑音を最小に抑え、記憶
情報の完全非破壊読み出しを可能にしていることである
The characteristics of this readout are that the magnetic field applied during readout is made small so as not to affect the magnetization state of the ferromagnetic film pattern 3 that stores information, and the readout line 7
By using its own sense current to generate the magnetization reversal magnetic field, noise from the magnetic field applied to the detection signal is minimized, making it possible to completely non-destructively read out stored information.

(発明の効果) 本発明により、従来問題になっていた磁化反転後の磁化
状態の不安定性、記憶密度の向上に伴う情報の読み出し
の不安定性がともに格段に改善された高性能の高密度磁
気記憶素子を実現できる。
(Effects of the Invention) The present invention provides high-performance, high-density magnetism that has significantly improved both the instability of the magnetization state after magnetization reversal, which has been a problem in the past, and the instability of information readout due to improved storage density. A memory element can be realized.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の基本セル構造例の外観図。第2図:第
1図の基本セルをマトリックス状に配置して、記憶素子
の形にした一例を示す図。第3図は本素子の情報読み出
しに利用する超伝導体膜パターン6の電気抵抗と印加磁
界との関係を示す図、第4図は本発明の基本セル構成に
使う膜面内に小さい一軸性の磁気異方性を有する低保磁
力強磁性体膜パターンと、膜面内に大きい一軸性の磁気
異方性を有する低保磁力強磁性体膜パターンの一斉回転
磁化反転モードの磁化曲線を示す図。第5図(a)〜(
d)は基本セルの断面構造図および情報書き込み過程を
例示する図。第6図(a)、(b)は情報を書き込んだ
状態の例を示す図。第7図(a)〜(d)は安定化され
たセルの磁化状態とそれに対応する磁化曲線を示す図。 第8図(a)、(b)は読み出し動作原理を示す図。第
9図は磁性体膜パターンを使った従来のメモリの一例を
示す図。 図において、1・・・超伝導体線、2・・・超伝導体線
、3・・・膜面内に大きい一軸磁気異方性を有するか、
または大きい保磁力を有する強磁性体膜パターン、4・
・・膜面内に小さい一軸磁気異方性を有するか、または
低保磁力を有する強磁性体膜パターン、3′、4′・・
・パターン3および4の磁化曲線、5・・・絶縁層、6
・・・情報読み出し用超伝導体膜パターン、7・・・導
体膜パターン6のリード線、8・・・超伝導体薄層、9
・・・絶縁層、10・・・Y−軸方向正の向き、11・
・・Y−軸方自負の向き、12・・・磁性膜パターン、
12′・・・磁化が反転している磁性膜パターン。
FIG. 1 is an external view of an example of the basic cell structure of the present invention. FIG. 2: A diagram showing an example in which the basic cells of FIG. 1 are arranged in a matrix to form a memory element. Fig. 3 is a diagram showing the relationship between the electrical resistance of the superconductor film pattern 6 used for reading information of this device and the applied magnetic field, and Fig. 4 is a diagram showing the relationship between the electrical resistance and the applied magnetic field of the superconductor film pattern 6 used for reading information of this device. The magnetization curves of a low coercive force ferromagnetic film pattern with a magnetic anisotropy of figure. Figure 5(a)-(
d) is a cross-sectional structural diagram of a basic cell and a diagram illustrating an information writing process. FIGS. 6(a) and 6(b) are diagrams showing an example of a state in which information has been written. FIGS. 7(a) to 7(d) are diagrams showing the magnetization state of a stabilized cell and the corresponding magnetization curve. FIGS. 8(a) and 8(b) are diagrams showing the principle of read operation. FIG. 9 is a diagram showing an example of a conventional memory using a magnetic film pattern. In the figure, 1... superconductor wire, 2... superconductor wire, 3... has large uniaxial magnetic anisotropy in the film plane,
or a ferromagnetic film pattern with a large coercive force, 4.
...Ferromagnetic film pattern with small uniaxial magnetic anisotropy in the film plane or low coercive force, 3', 4'...
- Magnetization curves of patterns 3 and 4, 5... insulating layer, 6
. . . Superconductor film pattern for reading information, 7 . . Lead wire of conductor film pattern 6, 8 . . . Superconductor thin layer, 9
...Insulating layer, 10...Y-axis direction positive direction, 11.
...Y-axis direction, 12...magnetic film pattern,
12'...Magnetic film pattern with reversed magnetization.

Claims (1)

【特許請求の範囲】[Claims]  基板上に膜面内の一軸性磁気異方性の方向が同じで、
その大きさ、または保磁力の少なくともいずれかが互い
に異なる2つの磁性体膜パターンを非磁性層を介して重
ねて置き、第1の磁性体膜パターンに膜面内の一軸磁気
異方性定数、または保磁力の少なくともいずれかが小さ
い磁性体膜を、第2の磁性体膜パターンに膜面内の一軸
磁気異方性定数、または保磁力の少なくともいずれかが
大きい磁性体膜をそれぞれ用い、第3の超伝導体パター
ンを第2の磁性体膜パターンに接して、第1の磁性体膜
パターンがある側と反対側に重ねた3層構造パターンの
上下に第1の導体線、第2の導体線を該磁性体膜パター
ンの位置で互いに交差するように配置し、第3の超伝導
体パターンには電流印加用のリード線を取り付けてある
ことを特徴とする磁気記憶素子。
The direction of uniaxial magnetic anisotropy in the film plane is the same on the substrate,
Two magnetic film patterns having different sizes or coercive forces are placed one on top of the other with a nonmagnetic layer interposed therebetween, and the first magnetic film pattern has an in-plane uniaxial magnetic anisotropy constant, Alternatively, a magnetic film with a small coercive force or a magnetic film with a large in-plane uniaxial magnetic anisotropy constant or a large coercive force is used as the second magnetic film pattern, respectively. The superconductor pattern No. 3 is in contact with the second magnetic film pattern, and the three-layer structure pattern is stacked on the side opposite to the side where the first magnetic film pattern is. A magnetic memory element characterized in that conductor wires are arranged so as to cross each other at the position of the magnetic film pattern, and a lead wire for applying a current is attached to the third superconductor pattern.
JP1144895A 1989-06-06 1989-06-06 Magnetic storage element Expired - Lifetime JP2797443B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1144895A JP2797443B2 (en) 1989-06-06 1989-06-06 Magnetic storage element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1144895A JP2797443B2 (en) 1989-06-06 1989-06-06 Magnetic storage element

Publications (2)

Publication Number Publication Date
JPH0312092A true JPH0312092A (en) 1991-01-21
JP2797443B2 JP2797443B2 (en) 1998-09-17

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Country Link
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5276639A (en) * 1990-04-18 1994-01-04 Nec Corporation Superconductor magnetic memory cell and method for accessing the same
CN107527704A (en) * 2016-06-20 2017-12-29 深圳市安普盛科技有限公司 The magnetizer structure of two-dimensional directional magnetic conduction

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5276639A (en) * 1990-04-18 1994-01-04 Nec Corporation Superconductor magnetic memory cell and method for accessing the same
CN107527704A (en) * 2016-06-20 2017-12-29 深圳市安普盛科技有限公司 The magnetizer structure of two-dimensional directional magnetic conduction

Also Published As

Publication number Publication date
JP2797443B2 (en) 1998-09-17

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