在多铁质物质中对地形磁极子的直接观测
Song Bao1, Zhao-Long Gu1, Yanyan Shangguan1
1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, China.
Nature communications
|September 29, 2023
概括
研究人员使用中子光谱学直接观察了Fe2Mo3O8中的磁性和声特性混合激发的磁极子,即 Fe2Mo3O8. 这一发现揭示了来自合激发的新拓状态.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 这就是Spintronics.
背景情况:
- 马格农极子是具有磁性 (magnon) 和声音 (phonon) 特性的混合激发.
- 它们对异国情调的自旋和磁性现象至关重要,但缺乏直接的光谱证据.
- 观察马格农极子是理解先进材料特性的关键.
研究的目的:
- 为马格农极子存在提供直接的光谱证据.
- 为了研究磁声声合在形成这些混合激发的作用.
- 为了探索观察到的马格农极子的拓性质.
主要方法:
- 采用中子光谱学来探测多铁体Fe2Mo3O8.8中的激发.
- 测量是在磁性订单温度以下进行的,以观察低能激发.
- 分析的重点是磁子和声子的波段结构和光谱特征.
主要成果:
- 直接观察具有明显混合磁性和音声特征的磁性极子.
- 一个清晰的能量隙在磁声波带交叉处打开,创建分离的磁极波带.
- 带反向和拓学上非平凡状态的证据在磁极波段内.
- 由Dzyaloshinskii-Moriya相互作用诱导的强烈的磁声声合被确定为原因.
结论:
- 这项研究提供了第一个直接的光谱证据,证明了马格农极子.
- 磁声合,特别是通过Dzyaloshinskii-Moriya相互作用,对于它们的形成至关重要.
- 发现带反转的,在拓上非碎的马格农极子为拓材料研究开辟了新的途径.
更多相关视频
相关概念视频
01:31Ferromagnetism
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
01:30Paramagnetism
2.5K
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...
2.5K
01:24Potential Due to a Magnetized Object
311
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...
311
01:26Diamagnetism
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
01:31Magnetic Susceptibility and Permeability
1.2K
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...
1.2K
01:17Theory of Metallic Conduction
1.4K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.4K