不均質の狭間半導体における室温ジオメトリック磁気抵抗強化
1NEC Research Institute, 4 Independence Way, Princeton, NJ 08540, USA. Department of Physics and Astronomy, Ohio University, Athens, OH 45701, USA.
Science (New York, N.Y.)
|September 1, 2000
まとめ
金を含むインジウムアンチモナイドディスクの室温幾何学的磁気抵抗は,4.0Tで750,000%に達しました. この効果は,電流の傾斜によって引き起こされ,磁場検出アプリケーションの可能性を示しています.
科学分野:
- 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:
- 幾何学磁気抵抗 (GMR) は,特定の幾何学と磁場を持つ材料で観察される現象です.
- インジウムアンチモニド (InSb) は,興味深い電子特性を有する半導体です.
研究 の 目的:
- 金の不均一性を持つインジウムアンチモニドのヴァン・デル・パウのディスクの室温幾何学的磁気抵抗を調査する.
- 磁気抵抗の磁場強度と不均一性の大きさの依存性を分析する.
主な方法:
- 均質な非磁性インジウムアンチモニドを使用した対称なヴァン・デル・パウフ円盤の製造.
- 円盤の中に同心的な黄金の不均一性を埋め込む.
- 室温で様々な磁場 (0.05T,0.25T,4.0T) に対する抵抗の測定.
主要な成果:
- 非常に高い室温の幾何学的な磁気抵抗を達成しました:0.05 Tで100%で,0.25 Tで9100%で,4.0 Tで750,000%です.
- 大きな不均一性の発症フィールドまで,フィールド独立の抵抗が観察され,その後に急速な増加が続いた.
- 観測された磁気抵抗を,金不均一性周りの電流のフィールド依存の傾きと相関させた.
結論:
- この研究は,InSb/Auシステムにおいて,室温の幾何学的な磁気抵抗効果が有意であることを示しています.
- この結果は,敏感な磁場検出のためのこのような構造の潜在能力を強調しています.
- 不均一性の周りの電流の傾きは,観測された高磁気抵抗を制御する重要なメカニズムです.
関連する概念動画
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:30Paramagnetism
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
01:31Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
01:24Metal-Semiconductor Junctions
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
01:27Biasing of Metal-Semiconductor Junctions
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...