JPH10134560A - Magnetic memory - Google Patents
Magnetic memoryInfo
- Publication number
- JPH10134560A JPH10134560A JP8302425A JP30242596A JPH10134560A JP H10134560 A JPH10134560 A JP H10134560A JP 8302425 A JP8302425 A JP 8302425A JP 30242596 A JP30242596 A JP 30242596A JP H10134560 A JPH10134560 A JP H10134560A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- layer
- magnetic layer
- magnetization
- magnetic memory
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F10/00—Thin magnetic films, e.g. of one-domain structure
- H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
- H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
- H01F10/3254—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、磁性層の磁化の向
きによって情報を記録する磁性メモリに関する。[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic memory for recording information according to the direction of magnetization of a magnetic layer.
【０００２】[0002]
【従来の技術】磁性層と非磁性層との積層膜が、磁性層
の磁化の状態に応じて、その電気抵抗に大きな変化を生
じる現象は、巨大磁気抵抗効果（ＧＭＲ効果）と呼ばれ
ている。特開平７−６６０３３号公報には、この現象を
利用した磁性メモリが提案されており、この磁性メモリ
においては、非磁性層を挟んで上下に形成された磁性層
の磁化容易軸は、磁性層と同一面内に存在し、抵抗変化
を検出するためのセンス電流は磁性層の膜面に対して平
行に流れている。一方、十分なＳ／Ｎを得るために、磁
化容易軸を情報記録時に電流を流すためのワード線と直
交させることが一般的である。2. Description of the Related Art A phenomenon in which a laminated film of a magnetic layer and a non-magnetic layer causes a large change in electric resistance in accordance with the state of magnetization of a magnetic layer is called a giant magnetoresistance effect (GMR effect). I have. Japanese Patent Application Laid-Open No. 7-66033 proposes a magnetic memory utilizing this phenomenon. In this magnetic memory, the easy axis of the magnetic layer formed above and below the non-magnetic layer is such that the magnetic layer has an easy axis. And a sense current for detecting a resistance change flows in parallel with the film surface of the magnetic layer. On the other hand, in order to obtain a sufficient S / N, it is general that the axis of easy magnetization is orthogonal to a word line for flowing a current during information recording.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記の
磁性メモリにおいては、磁性層の膜面内に磁化容易軸を
有するため、成膜過程でワード線と直交するように磁化
容易軸の向きを制御する必要があるが、これは非常に困
難である。例えば、磁性層の形状に異方性を与え、長手
方向に磁化容易軸を有する形状磁気異方性を利用するこ
となどが考えられるが、その場合は、記憶容量上の損失
が発生するため実用的であるとは言い難い。さらに、こ
のような磁性メモリの各セルは、同一のセンス線に対し
て直列に配置されているため、セル数が増せば同一のセ
ンス線の全抵抗が増大する。したがって、同一センス線
上の１個のセルの抵抗が変化したとしても、全抵抗に対
する抵抗変化率は極めて微小であるために、検出感度が
低下することは避けられないという問題がある。However, in the above-mentioned magnetic memory, since the magnetic layer has an easy axis in the film plane of the magnetic layer, the direction of the easy axis is controlled so as to be orthogonal to the word line during the film forming process. But this is very difficult. For example, it is possible to give anisotropy to the shape of the magnetic layer and use shape magnetic anisotropy having an easy axis of magnetization in the longitudinal direction. It is hard to say. Furthermore, since each cell of such a magnetic memory is arranged in series with the same sense line, the total resistance of the same sense line increases as the number of cells increases. Therefore, even if the resistance of one cell on the same sense line changes, the rate of change in resistance with respect to the total resistance is extremely small, so that there is a problem that the detection sensitivity is inevitably reduced.
【０００４】[0004]
【課題を解決するための手段】最近、ＧＭＲ素子におい
て、センス電流は、膜面に平行に流れる場合よりも、膜
面に垂直に流れた場合の方が、大きな抵抗変化が得られ
ることが理論的に推測されており、それを裏付ける実験
結果が報告されている（日本応用磁気学会、第８８回研
究会試料、１〜６頁）。また、スピントンネル結合を利
用することにより、センス電流を膜面に対して垂直に流
し、各セルをセンス線に対して並列に配置したメモリが
提案されている（日本応用磁気学会誌、Ｖｏｌ．２０，
Ｎｏ．２，３６９〜３７２頁、１９９６年）。このスピ
ントンネル結合では磁性層間に介在されるスペーサとし
ての非磁性層は絶縁体によって形成されており、膜面に
対して垂直方向の抵抗がある程度大きいため、センス電
流を膜面に対して垂直に流すことが可能となる。Recently, it has been theorized that in a GMR element, a larger resistance change is obtained when a sense current flows perpendicular to the film surface than when it flows parallel to the film surface. Experimental results that support this have been reported (Japan Society of Applied Magnetics, sample of the 88th workshop, pages 1-6). Also, a memory has been proposed in which a sense current is caused to flow perpendicularly to the film surface by using spin tunnel coupling, and each cell is arranged in parallel with the sense line (Journal of the Japan Society of Applied Magnetics, Vol. 20,
No. 2, 369-372, 1996). In this spin tunnel coupling, the nonmagnetic layer as a spacer interposed between the magnetic layers is formed of an insulator, and has a somewhat large resistance in a direction perpendicular to the film surface. It is possible to flow.
【０００５】本発明者は、かかる現象に着目し、磁性層
として垂直磁気異方性を有する磁性膜を使用すれば、従
来のように、膜面内で磁化容易軸の向きを制御するとい
う工程上の困難性を伴わずに、高いＳ／Ｎを達成するこ
とができ、しかも、センス電流を膜面に垂直な方向に流
すことができるので、セルを並列に配置することによる
感度向上も期待できるとの着想を得て本発明を完成し
た。すなわち、本発明によれば、非磁性層の上下両面
に、垂直磁気異方性を有する磁性膜により形成された磁
性層がそれぞれ積層され、各磁性層の磁化の方向により
情報を記録する磁性メモリが提供される。The present inventor has paid attention to such a phenomenon, and if a magnetic film having perpendicular magnetic anisotropy is used as the magnetic layer, the process of controlling the direction of the axis of easy magnetization in the film plane as in the related art is performed. A high S / N ratio can be achieved without the above difficulties, and a sense current can flow in a direction perpendicular to the film surface. Therefore, it is expected that sensitivity is improved by arranging cells in parallel. The present invention was completed based on the idea that it can be achieved. That is, according to the present invention, a magnetic memory in which magnetic layers formed of magnetic films having perpendicular magnetic anisotropy are respectively laminated on the upper and lower surfaces of a nonmagnetic layer, and information is recorded according to the direction of magnetization of each magnetic layer Is provided.
【０００６】[0006]
【発明の実施の形態】以下、本発明の磁性メモリの構成
について、図１を参照しながら説明する。図１におい
て、非磁性基板１上に、下部電極２、第１の磁性層３、
非磁性層（以下、スペーサ層と称する）４、第２の磁性
層５及び上部電極６が順次積層されている。第１及び第
２の磁性層３、５を構成する材料としては、垂直方向に
磁化容易軸を有するものであれば、どのようなものでも
よく、例えば、ＣｏＣｒ合金、Ｃｏ−γＦｅ2Ｏ3、Ｂａ
フェライトなどをあげることができる。そして、これら
の磁性層３、５は、その保磁力に差が設けられており、
例えば、第１の磁性層３の保磁力が大きく、第２の磁性
層５の保磁力が小さくなっている。このような保磁力の
差は、例えば、Ｃｏ基合金の組成や成膜条件を変化させ
ることによって容易に実現することができる。上記の積
層体の側方には、情報記録用ワード線７が、各磁性層
３、５の磁化容易軸と直交するように（紙面に垂直な方
向に）配置されている。又、下部及び上部電極２、６は
そのままセンス線として機能するか、又は、図示しない
外部のセンス線に接続されている。又、スペーサ層４を
形成する材料は、非磁性体であればどんなものであって
もよく、さらに、このスペーサ層４を絶縁体によって形
成すると、センス電流を膜面に対して垂直に流すことが
可能となり、メモリの感度向上に一層有効である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a magnetic memory according to the present invention will be described below with reference to FIG. In FIG. 1, a lower electrode 2, a first magnetic layer 3,
A non-magnetic layer (hereinafter, referred to as a spacer layer) 4, a second magnetic layer 5, and an upper electrode 6 are sequentially laminated. The first and second magnetic layers 3 and 5 may be made of any material as long as it has an easy axis of magnetization in the vertical direction, such as a CoCr alloy, Co-γFe 2 O 3 , Ba
Ferrite and the like can be given. These magnetic layers 3 and 5 are provided with a difference in coercive force.
For example, the coercive force of the first magnetic layer 3 is large, and the coercive force of the second magnetic layer 5 is small. Such a difference in coercive force can be easily realized by, for example, changing the composition of the Co-based alloy and the film forming conditions. A word line 7 for information recording is arranged on the side of the laminated body so as to be orthogonal to the easy axis of magnetization of each of the magnetic layers 3 and 5 (in a direction perpendicular to the plane of the paper). Further, the lower and upper electrodes 2 and 6 function as they are as sense lines, or are connected to external sense lines (not shown). The material for forming the spacer layer 4 may be any material as long as it is a non-magnetic material. Further, if the spacer layer 4 is formed of an insulator, a sense current can be made to flow perpendicular to the film surface. This is more effective in improving the sensitivity of the memory.
【０００７】このような構成の磁性メモリにおいて、ワ
ード線７に電流を流すと、電流に応じた磁界が発生し、
第１及び第２の磁性層３及び５の磁化の向きを反転さ
せ、情報の記録が行われる。図２は、図１の磁性メモリ
において、ワード線７に紙面の表側から裏側へ向けて、
十分な電流を流した状態を示す。このとき、ワード線７
から発生する磁界は紙面上で時計回りであるため、第１
及び第２の磁性層３及び５の磁化の向きは図中矢線で示
したように、共に下向きとなる。第１及び第２の磁性層
３及び５の磁化の向きが平行であるため、この状態にお
けるセンス線の抵抗は低くなる。図３は、同じくワード
線７に紙面の裏側から表側へ向けて、保磁力の大きい第
１の磁性層３の磁化の向きは反転させず、保磁力の小さ
い第２の磁性層５の磁化の向きのみを反転させる磁界を
発生させるような電流を流した状態を示す。このとき、
ワード線７から発生する磁界は紙面上で反時計回りであ
り、図中矢線で示したように、第２の磁性層５の磁化の
向きのみ反転して上向きとなる。第１、第２の磁性層
３、５の磁化の向きが反平行であるため、前述したよう
なＧＭＲ効果が生じ、センス線の抵抗が高くなる。この
ようにして、センス線の抵抗の高低により情報を記録す
ることが可能となる。In the magnetic memory having such a configuration, when a current is supplied to the word line 7, a magnetic field corresponding to the current is generated.
Information is recorded by reversing the directions of magnetization of the first and second magnetic layers 3 and 5. FIG. 2 shows that, in the magnetic memory shown in FIG.
This shows a state where a sufficient current has flowed. At this time, the word line 7
Since the magnetic field generated from
The directions of magnetization of the second magnetic layers 3 and 5 are both downward as indicated by arrows in the figure. Since the magnetization directions of the first and second magnetic layers 3 and 5 are parallel, the resistance of the sense line in this state is low. FIG. 3 also shows that the direction of the magnetization of the first magnetic layer 3 having a large coercive force is not reversed from the back side to the front side of the page of the word line 7 and the magnetization This shows a state in which a current that generates a magnetic field that reverses only the direction is applied. At this time,
The magnetic field generated from the word line 7 is counterclockwise on the paper, and only the direction of the magnetization of the second magnetic layer 5 is inverted and upward as indicated by the arrow in the drawing. Since the magnetization directions of the first and second magnetic layers 3 and 5 are antiparallel, the GMR effect as described above occurs, and the resistance of the sense line increases. In this manner, information can be recorded based on the level of the resistance of the sense line.
【０００８】[0008]
【実施例】図１において、基板１として、ガラス基板、
電極２、６としてＣｒ、スペーサ層４として、Ａｌ
2Ｏ3、又、第１及び第２の磁性層３、５としてＣｏＣｒ
2Ｏを使用し、磁性メモリを作製した。第１及び第２の
磁性層３及び５は、スパッタリング法による成膜中の基
板加熱温度を変化させることにより、第１の磁性層の保
磁力を大きく、第２の磁性層の保磁力を小さくしてあ
る。この磁性メモリについて、前述したようにワード線
７に２種類の磁界を発生させるような電流を流すことに
より情報の記録を行ったところ、高い感度及び高いＳ／
Ｎを有することが確認された。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
Cr for electrodes 2 and 6, Al for spacer layer 4
2 O 3 , and CoCr as the first and second magnetic layers 3 and 5.
A magnetic memory was fabricated using 2 O. The first and second magnetic layers 3 and 5 increase the coercive force of the first magnetic layer and decrease the coercive force of the second magnetic layer by changing the substrate heating temperature during film formation by the sputtering method. I have. As described above, when information was recorded on this magnetic memory by applying a current that generates two types of magnetic fields to the word line 7, high sensitivity and high S / S were obtained.
N was confirmed.
【０００９】[0009]
【発明の効果】以上詳細に説明したとおり、本発明によ
れば、非磁性層の上下両面に形成される磁性層を膜面に
垂直な磁化容易軸を有する磁性材料で構成したため、磁
性層の成膜過程における磁化容易軸の向きの制御が容易
であり、また、抵抗の変化が大きく感度の高い磁性メモ
リを得ることが可能となる。As described above in detail, according to the present invention, the magnetic layers formed on the upper and lower surfaces of the nonmagnetic layer are made of a magnetic material having an easy axis of magnetization perpendicular to the film surface. It is easy to control the direction of the axis of easy magnetization during the film formation process, and it is possible to obtain a magnetic memory with a large change in resistance and high sensitivity.
【図１】本発明の磁性メモリの構成を示す概略縦断面図
である。FIG. 1 is a schematic vertical sectional view showing a configuration of a magnetic memory according to the present invention.
【図２】本発明の磁性メモリの低抵抗状態を示す概略縦
断面図である。FIG. 2 is a schematic longitudinal sectional view showing a low resistance state of the magnetic memory of the present invention.
【図３】本発明の磁性メモリの高抵抗状態を示す概略縦
断面図である。FIG. 3 is a schematic longitudinal sectional view showing a high resistance state of the magnetic memory of the present invention.
１ 非磁性基板 ２ 下部電極 ３ 第１の磁性層 ４ スペーサ層（非磁性層） ５ 第２の磁性層 ６ 上部電極 ７ ワード線 REFERENCE SIGNS LIST 1 non-magnetic substrate 2 lower electrode 3 first magnetic layer 4 spacer layer (non-magnetic layer) 5 second magnetic layer 6 upper electrode 7 word line
Claims (1)
する磁性層がそれぞれ積層され、前記各磁性層の磁化の
方向により情報を記録する磁性メモリにおいて、 前記磁性層が垂直磁気異方性を有する磁性膜により形成
されていることを特徴とする、磁性メモリ。1. A magnetic memory in which magnetic layers having magnetic anisotropy are laminated on upper and lower surfaces of a non-magnetic layer, respectively, and information is recorded according to the direction of magnetization of each of the magnetic layers. A magnetic memory formed of a magnetic film having anisotropy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30242596A JP3351694B2 (en) | 1996-10-28 | 1996-10-28 | Magnetic memory |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30242596A JP3351694B2 (en) | 1996-10-28 | 1996-10-28 | Magnetic memory |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10134560A true JPH10134560A (en) | 1998-05-22 |
| JP3351694B2 JP3351694B2 (en) | 2002-12-03 |
Family
ID=17908775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30242596A Ceased JP3351694B2 (en) | 1996-10-28 | 1996-10-28 | Magnetic memory |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3351694B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0933782A2 (en) * | 1998-01-28 | 1999-08-04 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| EP0959475A2 (en) * | 1998-05-18 | 1999-11-24 | Canon Kabushiki Kaisha | Magnetic thin film memory and recording and reproducing method and apparatus using such a memory |
| US6628542B2 (en) | 2000-01-07 | 2003-09-30 | Sharp Kabushiki Kaisha | Magnetoresistive device and magnetic memory using the same |
-
1996
- 1996-10-28 JP JP30242596A patent/JP3351694B2/en not_active Ceased
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0933782A2 (en) * | 1998-01-28 | 1999-08-04 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| EP0933782A3 (en) * | 1998-01-28 | 2000-05-03 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| US6219275B1 (en) | 1998-01-28 | 2001-04-17 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| US6654279B2 (en) | 1998-01-28 | 2003-11-25 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| US6847545B2 (en) | 1998-01-28 | 2005-01-25 | Canon Kabushiki Kaisha | Magnetic thin film element, memory element using the same, and method for recording and reproducing using the memory element |
| EP0959475A2 (en) * | 1998-05-18 | 1999-11-24 | Canon Kabushiki Kaisha | Magnetic thin film memory and recording and reproducing method and apparatus using such a memory |
| US6104632A (en) * | 1998-05-18 | 2000-08-15 | Canon Kabushiki Kaisha | Magnetic thin film memory and recording and reproducing method and apparatus using such a memory |
| EP0959475A3 (en) * | 1998-05-18 | 2000-11-08 | Canon Kabushiki Kaisha | Magnetic thin film memory and recording and reproducing method and apparatus using such a memory |
| US6628542B2 (en) | 2000-01-07 | 2003-09-30 | Sharp Kabushiki Kaisha | Magnetoresistive device and magnetic memory using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3351694B2 (en) | 2002-12-03 |
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