スピン極化スキャニングトンネリング顕微鏡による電流誘発磁化スイッチング
S Krause1, L Berbil-Bautista, G Herzog
1Institute of Applied Physics and Microstructure Research Center, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany. skrause@physnet.uni-hamburg.de
Science (New York, N.Y.)
|September 18, 2007
まとめ
研究者は,スピン極化電流とスキャニング探査機の先端を使用して,磁気データストレージの正確な制御を実証しました. この技術は,ナノスケールでの電流誘発磁気化の逆転を可能にし,高密度貯蔵技術の進歩をもたらします.
科学分野:
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
- ナノテクノロジー ナノテクノロジー
背景:
- スピン極化電流注入は,磁気データストレージのための有望な方法です.
- 高密度ストレージの開発には,磁気ビットに対する正確な制御が必要です.
研究 の 目的:
- スキャニングプローブの先端を使用して,個々の超パラ磁性ナノ島のローカル磁化スイッチングを実証する.
- 真空障壁を通過する電流誘発磁化逆転を調査するために.
- マグネティゼーションスイッチングへの貢献を分離し,定量化するために.
主な方法:
- 磁気スキャニングプローブの先端を使用して,個々の鉄ナノ島 (約. 100個の原子がある).
- 究極の解像度を得るために,スピン極化スキャニングトンネル顕微鏡を使用しています.
- スピントルク,電流による加熱,オーステッド場からの貢献を分離する.
主要な成果:
- 個々の超パラマグネット性鉄ナノ島の局所的なスイッチングが成功しました.
- 真空障壁を通過する電流誘発磁化逆転の実証.
- スイッチングメカニズムにおけるスピントルク,加熱,オーステッド場効果の定量化.
結論:
- 開発された技術は,原子スケールでの磁気化の精密で局所的な制御を可能にします.
- スイッチングへの根本的な貢献を理解することで,将来のデータストレージデバイスの設計が向上します.
- この研究は,革新的な高密度磁気データストレージ技術への道を開く.
関連する概念動画
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
01:24Potential Due to a Magnetized Object
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
01:26Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:25Magnetic Field due to Moving Charges
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
01:05Atomic Nuclei: Magnetic Resonance
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...