We studied response of the Josephson vortex lattice in layered superconductors to the high-frequency c-axis electric field. We found a simple relation connecting the dynamic dielectric constant with the perturbation of the superconducting phase, induced by oscillating electric field. Numerically solving equations for the oscillating phases, we computed the frequency dependences of the loss function at different magnetic fields, including regions of both dilute and dense Josephson vortex lattices. The overall behavior is mainly determined by the c-axis and in-plane dissipation parameters, which is inversely proportional to the anisotropy. The cases of weak and strong dissipation are realized in $\mathrm{Bi_{2}Sr_{2}CaCu_{2}O_{x}}$ and underdoped $\mathrm{YBa_{2}Cu_{3} O_{x}}$ correspondingly. The main feature of the response is the Josephson-plasma-resonance peak. In the weak-dissipation case additional satellites appear in the dilute regime mostly in the higher-frequency region due to excitation of the plasma modes with the wave vectors set by the lattice structure. In the dense-lattice limit the plasma peak moves to higher frequency and its intensity rapidly decreases, in agreement with experiment and analytical theory. Behavior of the loss function at low frequencies is well described by the phenomenological theory of vortex oscillations. In the case of very strong in-plane dissipation an additional peak in the loss function appears below the plasma frequency. Such peak has been observed experimentally in underdoped $\mathrm{YBa_{2}Cu_{3} O_{x}}$. It is caused by frequency dependence of in-plane contribution to losses rather then a definite mode of phase oscillations.
Vortex-flow electromagnetic emission in stacked intrinsic Josephson junctions
通过观察Josephson涡旋流电流-电压特性中的多个子分支，证实了在Bi $_2$ Sr $_2$ CaCu $_2$ O $_{8+x}$的叠层本征约瑟夫森结中存在由约瑟夫森涡旋晶格运动激发的集体横向等离子体模.我们还观察到了约瑟夫森涡旋晶格与集体横等离子体模共振产生微波辐射的现象，这为研制约瑟夫森涡旋流电磁振荡器提供了可能。
Collective Josephson vortex dynamics in a finite number of intrinsic Josephson junctions
本文报道了在Bi $_{2}$ Sr $_{2}$ CaCu $_{2}$ O $_{8+x}$单晶中由本征约瑟夫森结叠层中的约瑟夫森涡旋晶格激发的集体横向等离子体模的实验证实。通过分析系统的电流-电压特性的约瑟夫森涡流区域中的多个子分支的温度（$T$）和磁场（$H$）依赖性来确认激发。在近静态的约瑟夫森涡旋状态下，一个低的隧道偏置电流，观察到明显的磁阻振荡，这代表了沿c轴的三角晶格涡旋配置。在足够高的磁场和高偏置电流的动态涡旋状态下，观察到单个约瑟夫森涡旋流分支分裂成多个子分支。对不同$H$场的子分支的详细研究表明，子分支代表约瑟夫森涡旋晶格沿c轴的不同模式，具有从三角形到矩形晶格的不同构型。这些多个子分支合并到一个单一的曲线在一个特征温度，以上的约瑟夫森涡晶格的动力学结构转变是预期。
The Josephson vortex formed in a superconductor-insulator-superconductor (SIS) junction can affect the quantum mechanics of quasiparticles by creating an effective adiabatic potential determined by the inhomogeneous distribution of the phase difference of the order parameter along the junction. Starting from the quasiclassical version of the Bogoliubov-de Gennes (BdG) theory, we found the quasiparticle spectrum and the local density of states (DOS) both for the isolated Josephson vortex and the vortex chain. The spatially resolved DOS reveals a peculiar two-peak structure for each Josephson vo…
Triplet supercurrents in multilayer ferromagnetic Josephson junctions with misaligned magnetization can penetrate thicker ferromagnetic barriers compared to the singlet component. Although the static properties of these junctions have been extensively studied, the dynamic characteristics remain largely unexplored. Here we report a comprehensive electrodynamic characterization of multilayer ferromagnetic Josephson junctions composed of Co and Ho. By measuring the temperature-dependent current-voltage characteristics and the switching current distributions down to 0.3 K, we show that phase dynam…
Periodic oscillations of flux flow resistance in intrinsic Josephson junctions with various lateral sizes down to a size of non-linear core of Josephson vortex
为了研究Bi 2Sr 2CaCu 2 O 8 +d本征约瑟夫森结（IJJ）中的约瑟夫森涡旋晶格（JVL）的同相结构（矩形晶格），我们采用聚焦离子束刻蚀技术制备了不同横向尺寸的IJJ，并测量了面内磁场（H）下的磁通流阻（RFF）。我们发现，在一个与尺寸无关的临界场以上，在窄长IJs（0.29-2.77 mm）中，临界电流呈现夫琅和费模式，然后RFF~H以H 0周期振荡。最引人注目的是，这种振荡在亚微米IJs中变得像脉冲一样，这表明在脉冲之间，矩形JVL成为主要结构。
Periodic Oscillations of Josephson-Vortex Flow Resistance in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+y}$
为了研究本征约瑟夫森结中的约瑟夫森涡旋系统，我们测量了Bi ${}_2$ Sr ${}_2$ CaCu ${}_2$ O ${}_{8+y}$单晶中流动阻力随平行于$ab$面的磁场的变化。虽然它是已知的流动阻力增加顺利增加，增加领域，我们发现了新的振荡的涡流阻力在小电流制度。振荡的周期对应于为每个“{\it two}”约瑟夫森结添加“{\it one}”涡旋量子所需的场。沿$ab$平面的Josephson涡旋的晶格间距与结的尺寸之间的公度性与涡旋的流速有关。结果表明，在振荡状态下，约瑟夫森涡旋形成三角形格子。
Josephson Plasma Excitation and Vortex Oscillation Mode in Josephson Vortes State
研究了$_2$ $_2$ O $_2$单晶在平行于$ab$面的磁场中的约瑟夫森等离子体共振。我们发现了两种共振模式;一个出现在零场和绝对零度下的等离子体频率$ω_p$以上的高场中的较高频率处，另一个位于$ω_p$以下，并且仅在磁场中观察到，而没有相当大的场依赖性。在临界电流随机的单结模型中，数值模拟也发现了两条共振线。高频模式归因于约瑟夫森涡旋的周期性结构修改的约瑟夫森等离子体模式，而低频模式被解释为约瑟夫森涡旋的振荡。
We report numerical simulations of the nonlinear dynamics of Josephson vortices driven by strong dc currents in layered superconductors. Dynamic equations for interlayer phase differences in a stack of coupled superconducting layers were solved to calculate a drag coefficient $η(J)$ of the vortex as a function of the perpendicular dc current density $J$. It is shown that Cherenkov radiation produced by a moving vortex causes significant radiation drag increasing $η(v)$ at high vortex velocities $v$ and striking instabilities of driven Josephson vortices moving faster than a terminal velocity $…
I apply the recently developed formalism of generalized quasiclassical theory to show that using hybrid superconducting systems with non-collinear strong ferromagnets one can realize the Josephson junction between Berezinskii-type superconductors. The reported calculation reproduces main features observed in the recent experiment, namely the the slightly asymmetric double-slit Fraunhofer interference pattern of the Josephson current through the ferromagnetic vortex. The double-slit structure results from the spatially inhomogeneous Berezinskii state with the amplitude controlled by the local a…
The continuous development of superconducting electronics is encouraging several studies on hybrid Josephson junctions (JJs) based on superconductor/ferromagnet/superconductor (SFS) heterostructures, as either spintronic devices or switchable elements in quantum and classical circuits. Recent experimental evidence of macroscopic quantum tunneling and of an incomplete 0-pi transition in tunnel-ferromagnetic spin-filter JJs could enhance the capabilities of SFS JJs also as active elements. Here, we provide a self-consistent electrodynamic characterization of NbN/GdN/NbN spin-filter JJs as a func…
Collective Josephson Vortex Dynamics in Long Josephson Junction Stacks
我们研究了传统长约瑟夫森结（LJJ）堆和层状超导体中的集体相动力学，表现出本征LJJ行为。使用解释磁感应效应和局部电荷中性击穿的理论模型（即，电荷效应），我们发现在本征LJJ叠层如Bi $_2$ Sr $_2$ CaCu $_2$ O $_{8+y}$（BSCCO）中的Josephson涡旋的集体运动，包括Josephson等离子体模的色散和Swihart型速度，与常规LJJ叠层中的那些相比有显著的改变.在BSCCO中，充电效应$α$的强度小（即，$α\sim 0.1-0.4$），但它导致集体相动力学的显著变化，包括稳定性条件的变化。此外，我们表明，分裂的超导分支的电阻状态是由于集体运动的约瑟夫森涡旋。这些子分支在线性电流-电压状态下的扩展宽度取决于$α$，这表明了测量BSCCO中充电效应的另一种方法。
