Anisotropy effects on flux pinning and flux flow are strongly effective in cuprate as well as iron-based superconductors due to their intrinsically layered crystallographic structure. However $\textrm{Fe(Se,Te)}$ thin films grown on $\textrm{CaF}_2$ substrate result less anisotropic with respect to all the other iron based superconductors. We present the first study on the angular dependence of the flux flow instability, which occurs in the flux flow regime as a current driven transition to the normal state at the instability point ($I^*$,$V^*$) in the current-voltage characteristics. The voltage jumps are systematically investigated as a function of the temperature, the external magnetic field, and the angle between the field and the $\textrm{Fe(Se,Te)}$ film. The scaling procedure based on the anisotropic Ginzburg-Landau approach is successfully applied to the observed angular dependence of the critical voltage $V^*$. Anyway, we find out that $\textrm{Fe(Se,Te)}$ represents the case study of a layered material characterized by a weak anisotropy of its static superconducting properties, but with an increased anisotropy in its vortex dynamics due to the predominant perpendicular component of the external applied magnetic field. Indeed, $I^*$ shows less sensitivity to angle variations, thus being promising for high field applications.
Casimir Force between Vortex Matter in Anisotropic and Layered Superconductors
本文提出了一种新的方法来计算各向异性和层状超导体中范德华型的吸引性长程涡旋-涡旋相互作用。将涡旋线的统计力学映射到二维带电玻色子的虚时量子力学上，我们可以定义一个二维Casimir问题：被宽度为R的间隙隔开的两个（稀）涡旋物质半空间映射到通过大质量规范场相互作用的两个带电玻色子介电半平面上。我们确定了两个半平面之间的吸引力Casimir力，并表明它与Blatter和Geshkenbein先前发现的涡旋之间的范德华力的成对求和一致[Phys. Rev. Lett. 77、4958（1996）]
Size-induced depression of first-order transition lines and entropy-jump in extremely-layered nanocrystalline vortex matter
我们检测到的持久性的凝固和有序无序的一级转变线的纳米晶Bi $_{2}$ Sr $_{2}$ CaCu $_{2}$ O $_{8}$涡旋物质的相图下降到一个系统的大小小于一百涡旋。涡流凝固转变线的温度位置不改变通过减少样品的大小，虽然有一个相对于宏观涡流物质的过渡熵跳跃的耗尽。随着系统尺寸的减小，有序-无序相变场向上移动，这是由于涡旋的表面积与体积比增大，导致平均涡旋结合能减小。
Vortex lock-in transition and evidence for transitions among commensurate kinked vortex configurations in single-layered Fe arsenides
我们报告了一个角度依赖性的磁转矩$τ(θ)$内的单晶LaO $_{0.9}$ F $_{0.1}$ FeAs和SmO $_{0.9}$ F $_{0.1}$ FeAs的涡旋状态作为温度$T$和磁场$H$的函数的研究。在$θ=90^{\circ}$两侧的临界角$θ_c$处观察到尖锐峰，其中$θ$是$H$和平面间\emph{c}轴之间的角度。$θ_c$被解释为临界去钉扎角，其中被固有平面结构钉扎和锁定的涡旋晶格解锁并获得垂直于平面的分量。我们观察到作为$θ$的函数的一系列较小的复制品峰，并且随着$θ$从平面方向被扫走。这表明涡格周期和面间距离之间的可伸缩性效应导致额外的扭结涡结构。
Vortex Phase Diagram of Layered Superconductor Cu0.03TaS2 for H || c
测量了高质量Cu_（0.03）TaS_2单晶的磁化强度和各向异性电输运性质。观察到明显的峰效应，表明高质量和均匀性对峰效应至关重要。在磁场H对面内电阻率ρab的依赖关系中观察到一个扭折，||c，这对应于涡旋液相从活化行为到扩散行为的转变。在涡旋液相扩散区，面内电阻率ρab满足ρab $\propto$ H 0. 3关系，不符合自由磁通流动的Bardeen-Stephen定律。最后，给出了简化的Cu_（0.03）TaS_2的涡旋相图，||C给出了。
The carrier transport and the motion of a vortex system in a mixed state of an electron-doped high-temperature superconductors Nd2-xCexCuO4 were investigated. To study the anisotropy of galvanomagnetic effects of highly layered NdCeCuO system we have synthesized Nd2-xCexCuO4/SrTiO3 epitaxial films with non-standart orientations of the c-axis and conductive CuO2 layers relative to the substrate. The variation ofe the angle of inclination of the magnetic field B, relative to the current J, reveals that the behavior of both the in-plane r_xx(B) and the out-plane r_xy(B) resistivities in the mixed…
Second ac screening step as a probe for the first-order melting transition in layered vortex matter at intermediate temperatures
Centro Atómico Bariloche, CNEA（巴拉奥切原子中心）；Instituto de Nanociencia y Nanotecnología, CONICET-CNEA（纳米科学与纳米技术研究所）；Instituto Balseiro, CNEA and Universidad Nacional de Cuyo（巴尔塞罗研究所，阿根廷国家核能委员会和门多萨国立大学）；Laboratorio Nacional de Haces de Neutrones, CNEA（中子束国家实验室）；Sensores y dispositivos, Centro Atómico Bariloche, CNEA（传感器与器件部门，巴拉奥切原子中心）；Laboratoire des Solides Irradiés, CEA/DRF/IRAMIS, École Polytechnique, CNRS, Institut Polytechnique de Paris（辐照固体实验室，法国原子能和替代能源委员会/研究与发展局/放射性物质研究所，巴黎综合理工学院，法国国家科学研究中心，巴黎理工学院）
A Review of the Real Space Renormalization Group Analysis of the Two- Dimensional Coulomb Gas, the Kosterlitz-Thouless-Berezinski Transition, and Extensions to a Layered Vortex Gas
The carrier transport and the motion of a vortex system in the electron-doped high-temperature superconductors Nd2-xCexCuO4 in underdoped and optimally doped (x = 0135, 0.145, 0.15) regions, in the area of the evolution from antiferromagnetic to superconducting order were investigated. To study the anisotropy of the transport properties of highly layered NdCeCuO system we have synthesized Nd2-xCexCuO4/SrTiO3 epitaxial films of three types with different orientations of the c-axis and conductive CuO2 layers relative to the substrate. Such a set of samples allowed us to study the processes of bo…
Edge critical currents of dense Josephson vortex lattice in layered superconductors
本文计算了沿原子层超导体层施加大磁场$B$所产生的稠密约瑟夫森涡旋晶格的临界电流随场的变化关系。在干净的样品中，由于晶格与边界的相互作用，出现有限的临界电流。边界引起晶格的交替变形，在典型长度处在样品内部衰减，该典型长度大于约瑟夫森长度并且与磁场成比例地增加。这种变形的确切形状和沿表面流动的总电流由晶格在体块中的位置唯一地确定。总的最大约瑟夫森电流具有强振荡的整体1/B依赖性。与公知的夫琅和费依赖性相反，振荡周期对应于添加\emph{one flux quantum per two junctions}。由于与边界的相互作用，慢晶格运动的磁通流电压也随场振荡，与最近的实验一致。
We investigate the structure of quasiparticle states localized in a core of an Abrikosov vortex in a clean layered superconductor in the presence of planar defects. It is shown that even a highly transparent defect opens a minigap at the Fermi energy. Its magnitude, $E_g\simΔ\sqrt{R}$, exceeds the mean level spacing for the chiral branch, $ω_0\simΔ^2/E_F$, already for very small values of the reflection coefficient off the defect, $R\ll1$ ($Δ$ is the bulk gap). For $R\gtrsim\sqrt{Δ/E_F}$, formation of the minigap is accompanied by the appearance of subgap states localized along the defect, in …
