在旋转轨道的横向磁化合反铁磁铁磁铁
Taekoo Oh1, Sungjoon Park1, Bohm-Jung Yang1
1Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea; Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea; and Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Korea.
Physical review letters
|July 14, 2023
概括
一个新的理论解释了反铁磁体的横向磁化 (TM),揭示了它出现在晶体对称性破裂和基本状态离散时. 这种TM可以诱导异常平面的霍尔效应,有助于研究复杂的磁结构.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 磁力学 磁力学 是一种
- 材料科学 材料科学 材料科学
背景情况:
- 反铁磁铁除了传统的平行磁化外,还可以呈现垂直于应用磁场的横向磁化 (TM).
- 现有的TM解释,如旋转倾斜或集群磁多极排序,缺乏全面的显微理论.
- 需要一个一般的理论框架来理解TM在反铁磁铁.
研究的目的:
- 开发一个通用的微观理论,用于横向磁化 (TM) 在反铁磁体与集群磁多极排序.
- 根据对称性分析和旋转汉密尔顿特征,研究TM出现的条件.
- 探索TM与可观测的运输现象 (如异常平面的霍尔效应) 之间的关系.
主要方法:
- 使用经典的旋转哈密尔顿理论与旋转轨道合诱导的异性质构建一个一般的微观理论.
- 对称性分析以确定TM出现的必要条件.
- 对自旋哈密尔顿的分析,以将TM与退化的基态多元体 (离散与连续) 的性质相关联.
主要成果:
- 当晶体对称性被打破时出现TM,不包括反单元镜子,反单元双旋转和反转对称性.
- 当旋转汉密尔顿的退化基态多重体是离散的,而不是对称性禁止时,TM会始终出现.
- 对于连续基态多元体,TM通常不存在,除了在具有单离子异性质的特定几何条件下.
- 横向磁化可以诱导异常平面霍尔效应,提供一种探测多极反铁磁结构的方法.
结论:
- 开发的理论提供了对TM在集群磁多极排序的反铁磁体中的微观理解.
- 对称性和基本状态退化是控制TM出现的关键因素.
- TM与异常平面霍尔效应之间的联系为复杂的磁结构提供了一个新的实验探测器.
相关概念视频
Atomic Nuclei: Magnetic Resonance
689
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...
689
Atomic Nuclei: Nuclear Relaxation Processes
683
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.
683
Diamagnetism
2.4K
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....
2.4K
Ferromagnetism
2.4K
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...
2.4K
Atomic Nuclei: Nuclear Spin State Overview
1.0K
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...
1.0K
Atomic Nuclei: Nuclear Magnetic Moment
1.2K
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
1.2K


