関連する実験動画
Updated: Jul 11, 2026
11:41
Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
スピン・トランスファー・トルクによって引き起こされるナノマグネットの時間領域ダイナミクスの測定
I N Krivorotov1, N C Emley, J C Sankey
1Cornell University, Ithaca, NY 14853, USA. ink3@cornell.edu
Science (New York, N.Y.)
|January 18, 2005
まとめ
私たちは,スピン極化電流を用いてギガヘルツ磁気動力を測定しました. この研究は,ナノマグネットの磁気減圧に対する電気的制御を明らかにし,スピントロニックデバイスの理解を進めています.
科学分野:
- スピントロニクス (Spintronics) は,スピントロニクス (Spintronics) を開発したものです.
- 凝縮物質物理学 凝縮物質物理学
- マテリアルサイエンス 材料科学
背景:
- スピン極化電流は,磁気モーメントにトルクを与える.
- 磁気動力学の理解は,高度なスピントロニックデバイスの開発に不可欠です.
- 磁気特性に対する電気的制御は,デバイスエンジニアリングの新たな道を開く.
研究 の 目的:
- スピン極化電流のトルクによって引き起こされるギガヘルツスケールの磁力学を調査する.
- スピン・トランスファー駆動のスイッチング中の磁気モメントの動きを決定する.
- マグネティック・ダッピングを測定し,その電気的制御性を実証する.
主な方法:
- 磁気動力学の時間解像度測定.
- 時間の領域における磁気モメント運動の分析.
- ナノマグネットにおける磁気阻害の直接測定.
主要な成果:
- スピン極化電流によって誘発されたギガヘルツスケールの磁力学を観測した.
- スピン・トランスファー・スイッチング中の磁気モメントの完全な動きを特徴づけた.
- 静止状態のプレセシオンモードの測定されたオンタイム.
- 磁気ダッピングの直接測定が実証されました.
- マグネティック・ダッピングを電気的に制御できることを証明した.
結論:
- 時間解像度測定は,スピン・トランスファー・ダイナミクスに関する前例のない洞察を提供します.
- 磁気減圧の電気制御は,スピン極化電流を使用して達成できます.
- この研究は,調整可能な磁気特性を持つ新しいスピントロニックデバイスへの道を開く.
関連する概念動画
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...
01:13Torque On A Current Loop In A Magnetic Field
The most common application of magnetic force on current-carrying wires is in electric motors. These consist of loops of wire, which are placed between the magnets with a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate, thus converting electrical energy to mechanical energy.
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
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...
01:17Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...