Fluxon manipulation by nanoscale artifcial pinning lattices in cuprate superconductors

超导是一个令人兴奋的现象，有许多尚未解决的基本问题有待探索。相关实验需要在纳米尺度上对超导体进行图案化，以控制磁通量子，也称为磁通量子或涡旋。该项目旨在研究具有前所未有的密度、复杂性和最小钉扎位尺寸的定制钉扎景观图案的CuCuate高温超导(HTSC)薄膜中涡旋的静态和动态特性。理论上提出的非常规临界态，将研究钉扎势与缺陷尺寸、人工钉扎阵列中的涡旋熔化以及横向霍尔公度效应之间的关系。对磁通操纵的探索可能对器件有用，包括对高速涡旋动力学、复杂钉扎结构和涡旋棘轮效应的研究。尽管高温超导材料复杂的晶体结构对其技术可用性构成了挑战，但该项目将把这种敏感性转化为以前所未有的分辨率制造超导纳米结构的资产。在高温超导中，点缺陷是由氦离子以中等能量照射产生的，这种能量很容易抑制临界温度。利用宽场离子束通过模板掩模或He离子显微镜(HIM)的聚焦光束的阴影投影，可以将纳米尺度的钉扎景观图案化为HTSC。他们将通过各种实验进行进一步的研究。通过在HIM中辐射在HTSCs中创建超密度钉扎晶格是一项新技术，申请者最近首次展示了这一技术。它允许在晶格常数远低于伦敦穿透深度的人工钉扎晶格中探索到迄今无法获得的强磁通耦合的大小和参数范围。这些实验将测试在高温超导细胞中纳米制造通量相关结构的可实现的最小长度尺度，从而为进一步的研究提供重要的结果。对涡旋物理的理解以及新型功能材料和超快、低耗散超导电路的发展具有重要的意义。这可能导致基于铜酸盐超导体的改进的超小型磁场传感器(SQUID)。这项研究将由三个拥有互补专业知识和设备的合作伙伴进行：W.Lang(维也纳大学)、J.D.Pedarnig(林茨开普勒大学)和D.Kölle(Eberhard Karls Universityät Tübingen)。外部合作者将通过旋涡排列和旋涡动态的分子动力学模拟(V.Misko，安特卫普大学)和用于显示旋涡的本地探测器技术(H.Suderow，马德里自治大学)支持该项目。

Superconductivity is an exciting phenomenon with many unresolved fundamental questions to be explored. Relevant experiments require to pattern superconductors on the nanoscale for a control of magnetic flux quanta, also called fluxons or vortices.The project aims at static and dynamic properties of vortices in cuprate high-Tc superconductor (HTSC) thin films patterned with tailored pinning landscapes of unprecedented density, complexity and minimum size of pinning sites. Theoretically proposed unconventional critical states, the relation of pinning potential vs defect size, vortex melting in artificial pinning arrays and transverse Hall commensurability effects will be investigated. Exploration of fluxon manipulation, potentially useful for devices, includes studies on high-velocity vortex dynamics, on complex pinning structures and on vortex ratchet effects.While the complicated crystal structure of the HTSCs pose a challenge to their technical usability, this project will turn this susceptibility into an asset to fabricate superconducting nanostructures with unprecedented resolution. In HTSCs, point defects are created by Helium ion irradiation with moderate energy that readily suppress the critical temperature. Using shadow projection of a wide-field ion beam through a stencil mask or the focused beam of a He ion microscope (HIM), it is possible to pattern nanoscale pinning landscapes into HTSCs. They will be further investigated by various experiments.Creating ultradense pinning lattices in HTSCs by irradiation in a HIM is a novel technique, for the first time demonstrated recently by the applicants. It allows to explore a hitherto inaccessible size and parameter range of strong fluxon coupling in artificial pinning lattices with lattice constants well below the London penetration depth. The experiments will test the achievable minimal length scales for nanofabrication of fluxon-related structures in HTSCs and, thus, provide important consequences for further research. Significant implications are expected on the understanding of vortex physics and on the development of new functional materials and ultrafast, low-dissipation superconducting circuits. This may lead to improved ultrasmall magnetic field sensors (SQUIDs) based on cuprate superconductors.The research will be performed by three partners with complementary expertise and equipment: W. Lang (University of Vienna), J. D. Pedarnig (Johannes Kepler University of Linz), and D. Kölle (Eberhard Karls Universität Tübingen). External collaborators will support the project with molecular-dynamic simulations of vortex arrangements and vortex dynamics (V. Misko, University of Antwerp) and with local probe techniques for the visualization of vortices (H. Suderow, Universidad Autónoma de Madrid).