在ilmenite-hematite矿物中,反相域和反向热延续磁性
概括
合成的伊尔梅尼特-血含有反相域和边界. 在高温样本中观察到的这些边界的高密度,对于获得反向高温磁性至关重要.
科学领域:
- 矿物物理 矿物物理
- 地磁主义 地磁主义
背景情况:
- 伊尔梅尼特 - 黑马提特固体溶液在古磁论中很重要.
- 要了解它们的磁性,就需要研究它们的微观结构.
研究的目的:
- 为了研究合成伊尔梅尼特-血的微观结构.
- 为了确定微观结构和磁性特性之间的关系,特别是逆热磁性磁性.
主要方法:
- 使用传输电子显微镜 (TEM) 检查合成伊尔梅尼特-血样本.
- 样品在不同的温度 (1300°C和900°C) 下被灭.
- 在磁场中冷却后,测量了磁性特性,包括恒温磁性.
主要成果:
- 传输电子显微镜首次揭示了在合成伊尔梅尼特-血中明确的反相域和边界.
- 从1300°C灭的样本显示出高密度的域边界.
- 从900°C灭的样本显示,域边界的密度明显较低.
- 只有具有高密度域边界的样本在磁场中冷却时获得了反向高温磁力.
结论:
- 反相域和边界的存在是合成伊尔梅尼特-黑马的关键微观结构特征.
- 这些域边界的高密度是这种矿物系统中获得逆热磁性磁性的必要条件.
相关概念视频
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...
Magnetic Field Lines
The representation of magnetic fields by magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. Each of the magnetic field lines forms a closed loop. The field lines emerge from the north pole (N), loop around to the south pole (S), and continue through the bar magnet back to the north pole.
Magnetic field lines follow several hard-and-fast rules:
Magnetic field lines follow several hard-and-fast rules:
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.
Ferromagnetism
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...
Paramagnetism
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...
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...


