在混合价值单分子磁铁 (CpiPr5) 中强迫场超过30 T
Hyunchul Kwon, K Randall McClain1, Jon G C Kragskow2
1US Navy, Naval Air Warfare Center, Weapons Division, Research Department, Chemistry Division, China Lake, California 93555, United States.
Journal of the American Chemical Society
|June 26, 2024
概括
新的荷和复合物表现出独特的磁性,荷化合物表现出创纪录的强制性,为先进的磁性材料铺平了道路. 这项研究探讨了基于兰他尼德的单分子磁铁.
科学领域:
- 无机化学
- 材料科学
- 磁力学
背景情况:
- 具有Ln-Ln σ-结合的混合价值迪兰化物复合物表现出高旋转基态和磁性异构性.
- 之前的研究集中在Gd,Tb和Dy,显示Tb和Dy变体具有很大的磁力强制性.
研究的目的:
- 合成和表征新的混合价值二甲化合物 (CpiPr5) 2Ln2I3对于荷 (Ho) 和埃尔 (Er).
- 研究这些新化合物的磁性特性,包括磁阻断,缓慢的磁放松和强制性场.
- 了解Ho和Er复合体之间不同磁性行为的起源.
主要方法:
- 新型混合价值迪兰化物复合物的合成: (CpiPr5) 2Ln2I3 (Ln = Ho, Er).
- 使用磁感应度测量和可变场磁化研究进行表征.
- 计算分析 (多配置计算) 和远红外磁光谱.
主要成果:
- 首个具有 Ln-Ln 键的 Ho 和 Er 分子化合物的成功合成.
- 由于自旋-自旋合和Ln-Ln结合电子,这两种复合体都表现出高自旋基态.
- 荷复合物 (1-Ho) 在28K以下表现出磁阻和556~4cm-1的旋转逆转屏障.
- 在低温下,霍尔复合体表现出创纪录的强迫场 (> 32 T).
- 复合物 (1-Er) 没有可观测的磁阻或缓慢的磁放松.
结论:
- 新的Ho和Er复合物代表了这些兰坦化物中具有Ln-Ln结合的第一个分子化合物.
- 在Ho和Er复合体之间观察到不同的磁性特性,与局部磁性异性相关.
- 由于高阻塞温度和创纪录的强迫性,霍尔复合体作为单分子磁铁具有特殊的潜力.
更多相关视频
08:42High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions
Published on: October 10, 2014
11.6K
09:43Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement
Published on: November 7, 2017
9.5K
相关概念视频
02:58Crystal Field Theory - Octahedral Complexes
26.3K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.3K
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
8.6K
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...
8.6K
03:02Colors and Magnetism
11.6K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.6K
01:27π Electron Effects on Chemical Shift: Overview
1.1K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.1K
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