Numerical Simulation of the Coupling between Split-Ring Resonators and Antiferromagnetic Magnons

二维和三维反铁磁振子的寿命：实验、理论和数值计算

Lifetimes of antiferromagnetic magnons in two and three dimensions: experiment, theory, and numerics

一个高分辨率的中子光谱技术被用来测量动量分辨的磁振子寿命在原型的二维和三维反铁磁体Rb 2 MnF 4和MnF 2，在整个布里渊区和广泛的温度范围。我们重新推导的理论的寿命产生的磁振子-磁振子散射，从而扩大其适用范围以外的渐近小区域的波矢和温度。相应的计算，结合一个小的贡献，反映与域边界的碰撞，产生良好的定量协议的数据。

反铁磁绝缘体中畴壁磁振子散射引起的热磁阻

Thermal magnetoresistance from magnon scattering from a domain wall in an antiferromagnetic insulator

本文理论研究了反铁磁绝缘体中畴壁在磁场作用下对磁振子热输运的调控，发现磁场解除磁振子模式简并并与畴壁反射共同导致热磁阻，提出畴壁可作为磁振子热流的可控元件。

Thermal squeezing and nonlinear spectral shift of magnons in antiferromagnetic insulators

We investigate the effect of magnon-magnon interactions on the dispersion and polarization of magnons in collinear antiferromagnetic (AF) insulators at finite temperatures. In two-sublattice AF systems with either uniaxial or biaxial magnetocrystalline anisotropies, we implement a self-consistent Hartree-Fock mean-field approximation to explore the nonlinear thermal interactions. The resulting nonlinear magnon interactions separate into two-magnon intra- and interband scattering processes. Furthermore, we compute the temperature dependence of the magnon bandgap and AF resonance modes due to no…

Theory of magnon-polaritons in quantum Ising materials

We present a theory of magnon-polaritons in quantum Ising materials, and develop a formalism describing the coupling between light and matter as an Ising system is tuned through its quantum critical point. The theory is applied to Ising materials having multilevel single-site Hamiltonians, in which multiple magnon modes are present, such as the insulating Ising magnet LiHoF$_4$ . We find that the magnon-photon coupling strengths may be tuned by the applied transverse field, with the coupling between the soft mode present in the quantum Ising material and a photonic resonator mode diverging at …

Spin Nernst Effect of Antiferromagnetic Magnons in the Presence of Spin Diffusion

Magnon spin Nernst effect was recently proposed as an intrinsic effect in antiferromagnets, where spin diffusion and boundary spin transmission have been ignored. However, diffusion processes are essential to convert a bulk spin current into boundary spin accumulation, which determines the spin injection rate into detectors through imperfect transmission. We formulate a diffusive theory to describe the detection of magnon spin Nernst effect with boundary conditions reflecting real device geometry. Thanks to the spin diffusion effect, the output signals in both electronic and optical detection …

在平面几何结构中控制磁子-光子耦合

Controlling magnon-photon coupling in a planar geometry

本研究在室温下利用高品质因数开口环谐振器和单晶YIG球体，通过改变球体尺寸及在谐振器内的位置，实验验证了磁子-光子耦合强度与射频磁场、自旋密度及磁偶极相互作用的理论依赖关系，实现了对相干耦合的控制。

On the nonlinear NMR and magnon BEC in antiferromagnetic materials with coupled electron-nuclear spin precession

We present a new study of nonlinear NMR and Bose-Einstein Condensation (BEC) of nuclear spin waves in antiferromagnetic MnCO3 with coupled electron and nuclear spins. In particular, we show that the observed behaviour of NMR signals strongly contradicts the conventional description of paramagnetic ensembles of noninteracting spins based on the phenomenological Bloch equations. We present a new theoretical description of the coupled electron-nuclear spin precession, which takes into account an indirect relaxation of nuclear spins via the electron subsystem. We show that the magnitude of the nuc…

基于倾斜反铁磁体 α-Fe2O3 中非互易、非简并超快自旋波的反铁磁磁振子自旋电子学

Antiferromagnetic magnon spintronic based on non-reciprocal and non-degenerated ultra-fast spin-waves in the canted antiferromagnet α-Fe2O3

本研究在 α-Fe2O3 中利用感应式与自旋电子学换能器及非局域逆自旋霍尔效应，实现了超快非互易反铁磁自旋波的传播测量与高效电学探测。

Voltage control of magnon spin currents in antiferromagnetic Cr2O3

Voltage-controlled spintronic devices utilizing the spin degree of freedom are desirable for future applications, and may allow energy-efficient information processing. Pure spin current can be created by thermal excitations in magnetic systems via the spin Seebeck effect (SSE). However, controlling such spin currents, only by electrical means, has been a fundamental challenge. Here, we investigate voltage control of the SSE in the antiferromagnetic insulator Cr2O3. We demonstrate that the SSE response generated in this material can be effectively controlled by applying a bias voltage, owing t…