JP2810077B2 - Scanning tunneling microscope - Google Patents
Scanning tunneling microscopeInfo
- Publication number
- JP2810077B2 JP2810077B2 JP1017634A JP1763489A JP2810077B2 JP 2810077 B2 JP2810077 B2 JP 2810077B2 JP 1017634 A JP1017634 A JP 1017634A JP 1763489 A JP1763489 A JP 1763489A JP 2810077 B2 JP2810077 B2 JP 2810077B2
- Authority
- JP
- Japan
- Prior art keywords
- sample
- chip
- image
- scanning
- image signal
- 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.)
- Expired - Lifetime
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- Analysing Materials By The Use Of Radiation (AREA)
- Measuring Magnetic Variables (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、磁区観察装置に係わり、特に表面磁化状態
を空間分解能10Å以下で観察するのに適した走査トンネ
ル顕微鏡に係わる。Description: BACKGROUND OF THE INVENTION The present invention relates to a magnetic domain observation apparatus, and more particularly to a scanning tunnel microscope suitable for observing a surface magnetization state at a spatial resolution of 10 ° or less.
従来の磁区観察手法で、最も空間分解能が高いもの
は、走査トンネル顕微鏡（特開昭62−139240号公報参
照）である。しかしこの方法は、運動するチツプ先端0.
1μｍ程度の微小領域に、レーザ光を収束照射する必要
があり、極めて高度の位置合わせ技術が要求される。Among the conventional magnetic domain observation techniques, the one having the highest spatial resolution is a scanning tunneling microscope (see Japanese Patent Application Laid-Open No. 62-139240). However, this method uses a moving tip.
It is necessary to converge and irradiate a laser beam to a minute area of about 1 μm, and an extremely sophisticated alignment technique is required.
〔発明が解決しようとする課題〕 本発明の目的は、高度な位置合わせ技術を用いること
なく、高分解能の磁区像が得られる走査トンネル顕微鏡
を提供することにある。[Problems to be Solved by the Invention] It is an object of the present invention to provide a scanning tunnel microscope capable of obtaining a high-resolution magnetic domain image without using an advanced alignment technique.
上記目的は、強磁性体試料からチツプの伝導帯に流れ
込んだ偏極電子が価電子帯に遷移する際放出される円偏
光を検出し、これを画像信号として像を形成することに
より達成される。The above object is achieved by detecting circularly polarized light emitted when polarized electrons flowing from the ferromagnetic sample into the conduction band of the chip transition to the valence band, and forming an image using this as an image signal. .
強磁性体からチツプの伝導帯に流れ込む電子は試料の
磁化方向を反映して偏極している。この偏極電子が伝導
帯から価電子帯に遷移する際様々な方向に光を放出する
が、その偏光状態は光の放出方向と遷移電子の偏極ベク
トルに依存して変化する。したがつて、この偏光状態を
検出し、これを画像信号として像を形成すると試料の磁
区像が得られる。The electrons flowing from the ferromagnetic material into the conduction band of the chip are polarized reflecting the magnetization direction of the sample. When the polarized electrons transition from the conduction band to the valence band, they emit light in various directions. The polarization state changes depending on the emission direction of the light and the polarization vector of the transition electrons. Accordingly, when this polarization state is detected and an image is formed using the polarization state as an image signal, a magnetic domain image of the sample is obtained.
以下、図を用いて、本発明による走査トンネル顕微鏡
の構成及びその動作原理を詳細に説明する。Hereinafter, the configuration of a scanning tunnel microscope according to the present invention and the operating principle thereof will be described in detail with reference to the drawings.
第１図は本発明による、走査トンネル顕微鏡の基本構
成図を示したものである。FIG. 1 shows a basic configuration diagram of a scanning tunnel microscope according to the present invention.
本発明の装置は、先鋭なガリウムヒ素チツプ１、チツ
プの位置を0.2Å以下の精度で３次元的に制御するピエ
ゾ素子２、とその駆動電源３、チツプの先端から放出さ
れる光を検出するための５個の右周り（もしくは左周
り）円偏光検出器4,5,6,7,8、これら検出器の出力信号
から画像信号を演算するための信号処理回路９、上記画
像信号を輝度信号として画像表示するCRTデイスプレイ1
0、より構成される。ここで、円偏光検出器４〜８は、
第２図に示すように、それぞれ1/4波長板12、直線偏光
子13、フオトマル14、より構成され、1/4波長板12もし
くは直線偏光子13を光軸15の周りに90゜回転させること
により、右周り、または左周りのどちらの円偏光検出器
としても利用できる。The apparatus of the present invention detects a sharp gallium arsenide chip 1, a piezo element 2 for controlling the position of the chip three-dimensionally with an accuracy of 0.2 ° or less, a driving power supply 3 for the chip, and light emitted from the tip of the chip. Clockwise (or counterclockwise) circularly polarized light detectors 4, 5, 6, 7, and 8, a signal processing circuit 9 for calculating an image signal from output signals of these detectors, CRT display 1 that displays images as signals
It consists of 0. Here, the circularly polarized light detectors 4 to 8 are:
As shown in FIG. 2, each of the よ り wavelength plate 12, the linear polarizer 13, and the photomultiplier 14 is rotated by 90 ° around the optical axis 15. Thus, it can be used as a clockwise or counterclockwise circularly polarized light detector.
試料11が強磁性帯の場合、試料からトンネル効果によ
つてチツプの伝導帯に流入した電子は、試料の磁化状態
を反映して偏極している。この偏極電子が価電子帯に遷
移する際±ｘ方向に放出する光は、それぞれ右周り円偏
光と右周り円偏光の混合となるが、＋ｘ方向に放出され
る右周り円偏光成分と、−ｘ方向に放出される右周り円
偏光成分の強度は遷移電子の偏極度に応じて異なる。
今、これらの強度をそれぞれ とし、 とすると、Axは試料の磁化ベクトルＭのｘ成分、Mxを反
映する。したがつて、上記チツプで試料面上を走査し、
右周り円偏光検出器４で を、右周り円偏光検出器５で を検出して、信号処理回路９で（１）式に従つてAxを演
算し、これを画像信号としてCRT10上に像を形成するこ
とにより、Mxを反映した磁区像を得ることができる。When the sample 11 is a ferromagnetic band, electrons flowing from the sample into the conduction band of the chip by the tunnel effect are polarized reflecting the magnetization state of the sample. The light emitted in the ± x direction when this polarized electron transitions to the valence band is a mixture of clockwise circularly polarized light and clockwise circularly polarized light, respectively, and a clockwise circularly polarized light component emitted in the + x direction, The intensity of the clockwise circularly polarized light component emitted in the −x direction differs depending on the degree of polarization of the transition electrons.
Now, each of these strengths age, Then, A x reflects the x component of the magnetization vector M of the sample, M x . Therefore, scan the sample surface with the above chip,
With clockwise circular polarization detector 4 With the clockwise circular polarization detector 5 By detecting and calculating the Supporting connexion A x to the signal processing circuit 9 (1), which by forming an image on CRT10 as an image signal, it is possible to obtain a magnetic domain image that reflects the M x .
−ｘ方向に放出される右周り円偏光成分 と、＋ｘ方向に放出される左周り円偏光成分 の強度が等しいことから、以下の方法でAxを求めること
もできる。＋ｘ方向に配置した円偏光検出器４の1/4波
長板12、もしくは直線偏光子13、を光軸の周りで連続回
転させると、円偏光検出器４からは、 なる値の直流成分に、 なる値の振幅と回転周波数の２倍の周波数を持つ交流成
分が重畳された出力信号が得られる。これらの値をそれ
ぞれ独立に検出し、（１）式を用いることによつてAxが
得られる。このとき、ロツクイン技術によつて、交流成
分を検出すると、信号雑音比の大きいAx信号を得ること
ができる。Clockwise circularly polarized component emitted in -x direction And left-handed circularly polarized light component emitted in + x direction Since the strength of equal, it is also possible to obtain the A x in the following way. When the quarter-wave plate 12 or the linear polarizer 13 of the circular polarization detector 4 arranged in the + x direction is continuously rotated around the optical axis, the circular polarization detector 4 outputs To the DC component An output signal is obtained in which an AC component having an amplitude of a certain value and a frequency twice the rotation frequency is superimposed. These values were detected independently Yotsute A x is obtained using the equation (1). At this time, Yotsute to Rotsukuin technology detects an AC component, it is possible to obtain a large A x signal of the signal-noise ratio.
同様な手法によつて、磁化ベクトルのｙ成分Myを反映
した磁区像を得ることができる。It is possible to obtain the magnetic domains image that reflects Yotsute, the y component M y of the magnetization vector in the similar method.
磁化ベクトルのｚ成分Mzを反映した磁区像を得る場
合、前記した２つの手法のうち後者の方法のみが有効で
ある。これは、−ｚ方向へ放出される光は試料が十分薄
く無いかぎり、試料に吸収されてしまうため、＋ｚ方向
（試料面の上方向）へ放出される光のみが利用可能であ
ることによる。To obtain a magnetic domain image that reflects the z component M z of the magnetization vector, only the latter method of the two methods described above is effective. This is because light emitted in the -z direction is absorbed by the sample unless the sample is sufficiently thin, so that only light emitted in the + z direction (upward of the sample surface) is available.
以上詳述したように、本発明によれば、磁性体表面の
磁区構造を10Å以下の高分解能で観察でき、その工業的
な価値は極めて高い。As described in detail above, according to the present invention, the magnetic domain structure on the surface of the magnetic body can be observed with a high resolution of 10 ° or less, and its industrial value is extremely high.
第１図は、本発明の一実施例の走査トンネル顕微鏡の構
成図、第２図は円偏光検出器の構成図である。 １……チツプ、２……ピエゾ素子、３……駆動電源、４
〜８……円偏光検出器、９……信号処理回路、10……CR
Tデイスプレイ、11……試料、12……1/4波長板、13……
直線偏光子、14……フオトマル、15……光軸。FIG. 1 is a configuration diagram of a scanning tunneling microscope according to one embodiment of the present invention, and FIG. 2 is a configuration diagram of a circular polarization detector. 1 ... chip, 2 ... piezo element, 3 ... drive power supply, 4
-8: Circular polarization detector, 9: Signal processing circuit, 10: CR
T display, 11 ... sample, 12 ... quarter wave plate, 13 ...
Linear polarizer, 14… photometric, 15… optical axis.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭62−139240（ＪＰ，Ａ) 特開 昭63−304183（ＪＰ，Ａ) 特開 平１−296180（ＪＰ，Ａ) 特公 平７−1687（ＪＰ，Ｂ２) 特許2585598（ＪＰ，Ｂ２) (58)調査した分野(Int.Cl.6，ＤＢ名) G01N 37/00 G01R 33/10 G01B 7/34 H01J 37/28 ＪＩＣＳＴファイル ＷＰＩ／Ｌ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-139240 (JP, A) JP-A-63-304183 (JP, A) JP-A-1-296180 (JP, A) 1687 (JP, B2) Patent 2585598 (JP, B2) (58) Fields investigated (Int. Cl. 6 , DB name) G01N 37/00 G01R 33/10 G01B 7/34 H01J 37/28 JICST file WPI / L
Claims (3)
に流れるトンネル電子流が、チツプと試料の距離に大き
く依存することを利用して、試料表面状態を原子レベル
で観察する走査トンネル顕微鏡において、上記トンネル
電子流によつて試料、もしくはチツプから放出される光
の偏光度を検出し、この偏光度を画像信号として像を得
ることを特徴とする走査トンネル顕微鏡。A scanning tunneling microscope for observing a surface state of a sample at an atomic level by utilizing a fact that a tunnel electron flow flowing from a chip to a sample or from a sample to a chip largely depends on a distance between the chip and the sample. A scanning tunneling microscope which detects the degree of polarization of light emitted from a sample or a chip by a tunnel electron flow and obtains an image using the degree of polarization as an image signal.
ぼ満たされた価電子帯から構成されており、試料から上
記伝導帯に流れ込んだ電子が、上記価電子帯に遷移する
際放出する光の円偏光度を画像信号として、像を得るこ
とを特徴とする特許請求の範囲１項記載の走査トンネル
顕微鏡。2. The band structure of the chip is composed of an empty conduction band and a valence band substantially filled, and electrons flowing from the sample into the conduction band are emitted when transitioning to the valence band. 2. The scanning tunnel microscope according to claim 1, wherein an image is obtained by using a degree of circular polarization of light as an image signal.
検出器を配置し、これらの検出器の出力信号間の演算結
果を画像信号として、像を得ることを特徴とする特許請
求の範囲２項記載の走査トンネル顕微鏡。3. A method according to claim 2, wherein a plurality of circularly polarized light detectors are arranged in a space around said chip, and an image is obtained by using a calculation result between output signals of these detectors as an image signal. 3. The scanning tunnel microscope according to claim 2, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1017634A JP2810077B2 (en) | 1989-01-30 | 1989-01-30 | Scanning tunneling microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1017634A JP2810077B2 (en) | 1989-01-30 | 1989-01-30 | Scanning tunneling microscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02199757A JPH02199757A (en) | 1990-08-08 |
| JP2810077B2 true JP2810077B2 (en) | 1998-10-15 |
Family
ID=11949299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1017634A Expired - Lifetime JP2810077B2 (en) | 1989-01-30 | 1989-01-30 | Scanning tunneling microscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2810077B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997001862A1 (en) * | 1995-06-26 | 1997-01-16 | Hitachi, Ltd. | Electron microscope and electron microscopy |
| JP2001108598A (en) * | 1999-10-12 | 2001-04-20 | Japan Science & Technology Corp | Scanning tunneling microscope emission converging apparatus |
-
1989
- 1989-01-30 JP JP1017634A patent/JP2810077B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02199757A (en) | 1990-08-08 |
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