低温拉曼光谱研究无声和自旋声合的近二维稀土基法兰西石矿
1Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009, India.
Journal of physics. Condensed matter : an Institute of Physics journal
|February 19, 2024
概括
弗朗西斯矿物中的稀土元素会影响磁性. DyCufr显示了与元磁转换相关的自旋声子合,而NdCufr则没有.
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
- 磁力学 磁力学 是一种
背景情况:
- 弗朗西斯石 (Cu3Bi(SeO3) 2O2Cl) 具有准二维结构和显著的磁性特征.
- 用稀土 (RE) 金属取代非磁性 (Bi) 引入了额外的磁中心,使磁性性能能够微调.
研究的目的:
- 调查稀土元素替代对法兰西石化合物的磁性和声子特性的影响.
- 探索旋声子合 (SPC) 和磁性转换之间的关系,特别是 induced-field-induced metamagnetic transitions (MMT) 的关系.
主要方法:
- 采用温度依赖的拉曼光谱法,研究基于RE的法兰西体 (RECufr) 中的音声振动,从11K到295K.
- 分析的重点是声软化和与磁性订序温度和MMT相关的无和性.
主要成果:
- 在研究的RECufr化合物中,自旋声子合 (SPC) 不同:在DyCufr中适度,在LaCufr中弱,在NdCufr中不存在.
- DyCufr 在其反铁磁排序温度 (T≈39 K) 下显示了两个拉曼活性声子的软化,表明中度SPC.
- 观察到MMT的强度和SPC的发展之间存在相关性,DyCufr中的强度MMT促进SPC,而NdCufr中的弱度MMT则没有.
结论:
- 弗朗西斯石的磁性特性可以通过稀土元素替代来调节,从而影响自旋声联.
- 旋声子合的存在和强度与磁性行为直接相关,特别是场诱导的超磁性转换.
相关概念视频
01:20Raman Spectroscopy: Overview
390
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
390
01:27Atomic Spectroscopy: Effects of Temperature
333
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
333
01:08NMR Spectroscopy: Spin–Spin Coupling
1.4K
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved...
1.4K
01:26Raman Spectroscopy Instrumentation: Overview
372
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
372
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.3K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.3K
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