自发的旋-反旋对及其拓过渡在状格子磁铁中的位置
Xiuzhen Yu1, Naoya Kanazawa2, Xichao Zhang3
1RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.
Advanced materials (Deerfield Beach, Fla.)
|September 15, 2023
概括
研究人员在热磁铁中根据需求创建了多个磁性拓状态. 他们使用磁场和电流证明了 skyrmions 和 bimerons 之间的相互转换,从而推进了 spintronics.
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:
- 像梅龙和斯基米翁这样的拓旋转纹理对于超导和量子计算中的新兴现象至关重要.
- 螺旋磁铁为操纵非线性旋转纹理提供了独特的机会,但由于拓保护,实现多个拓状态及其相互转换是具有挑战性的.
研究的目的:
- 为了证明在一个单一的磁体中按需创建多个拓状态.
- 为了研究不同拓旋转纹理之间的相互转换,如梅龙,双梅龙和斯基米龙.
- 探索磁场和电流等外部刺激对控制这些拓状态的作用.
主要方法:
- 利用磁铁Fe0.5 Co0.5 Ge来创建和研究拓旋转纹理.
- 研究了梅龙-反梅龙对 (N = ±1/2) 和双梅龙 (N = -1) 的形成.
- 应用了磁场并分析了磁形异构性,以诱导 skyrmions 和 bimerons 之间的转换.
- 使用电流来操纵双子,导致它们组装成斯基米翁格子.
主要成果:
- 成功地创建了多个拓状态,包括meron-antimeron对和双元,在Fe0.5 Co0.5 Ge. Ge. 中按需创建.
- 证明了 skyrmions 和 bimerons 之间的相互转换,由磁场和磁形异构的相互作用控制.
- 展示了由电流驱动的双胞胎操纵,导致它们组装成一个 skyrmion 格子.
结论:
- 这些发现证实了在单个磁体材料内设计和控制多个拓旋转状态的可行性.
- 提供了对操纵非线性自旋纹理的新见解,为先进的自旋电子设备铺平了道路.
- 突出了螺旋磁铁在需要精确控制拓现象的领域应用的潜力.
相关概念视频
01:03Atomic Nuclei: Nuclear Spin State Overview
998
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...
998
01:23Atomic Nuclei: Nuclear Relaxation Processes
676
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.
676
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
01:23Magnetic Field due to Moving Charges
8.8K
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
8.8K
00:59Atomic 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
02:54Trends in Lattice Energy: Ion Size and Charge
24.0K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
24.0K