まとめ
月面の岩石と塵のサンプルには,高いキュリー点 (680~780°C) があり,強力な磁気特性を示しています. いくつかのサンプルは安定した磁化を示し,おそらく重要な古代月の磁場で獲得された可能性があります.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 惑星科学 惑星科学
- ミネラル物理学 ミネラル物理学
背景:
- 月面のサンプルの磁気特性を理解することは,月の熱と磁気の歴史を解読する上で極めて重要です.
- 以前の研究では,月の岩石に磁性の存在が示されましたが,詳細な特徴づけは進行中です.
研究 の 目的:
- 月の岩石と塵のサンプルの磁気特性,特にキュリー点と残留強度,を決定する.
- これらのサンプルにおける磁気化の安定性と起源を調査する.
主な方法:
- キュリー点を特定するための熱磁気分析.
- 岩石の断片の残留強度の測定.
- 磁気安定性を評価するための脱磁化技術 (粘着性および熱性)
主要な成果:
- 岩石と塵のサンプルで680°Cから780°Cの間で,顕著なキュリーポイントが観察されました.
- 残留の強度は,サンプルごとに有意に変化した.
- 2つのサンプルは,高い残留強制性 (>50 oersteds) と安定した磁化を示した.
- 部分的な熱去磁化により,1500ガマを超える磁場での獲得が示唆された.
結論:
- 月面のサンプルは,鉄を含有する鉱物と一致する高温磁気相を持っています.
- 安定した磁気化の存在は,過去の月の磁場がかなり強かったことを示しています.
- これらの発見は,初期の月のダイナモと熱進化のモデルに寄与する.
関連する概念動画
Magnetic 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...
Magnetic Fields
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...
Diamagnetism
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.
Magnetism
Magnets are commonly found in everyday objects, such as toys, hangers, elevators, doorbells, and computer devices. Experimentation on these magnets shows that all magnets have two poles: one is labeled north (N) and the other south (S). Magnetic poles repel if they are alike and attract if unlike. Moreover, both poles of a magnet attract unmagnetized pieces of iron.
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
Magnetic Moment of an Electron
Electrons revolving around a nucleus are analogous to a circular current carrying loop. This current produces a magnetic dipole moment proportional to the electron's orbital angular momentum. Since the orbital angular momentum is quantized in terms of the reduced Planck's constant, the dipole moment is quantized in the Bohr Magneton. The value of the Bohr magneton is 9.27 x 10-24 Am2. Electrons also have an intrinsic spin angular momentum, and the associated spin magnetic moment is...
Potential 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...


