Fluxon manipulation by nanoscale artifcial pinning lattices in cuprate superconductors

超导是一种令人兴奋的现象，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绘制超导体的图形，以控制磁通量子，也称为通量子或漩涡。该项目旨在研究铜高tc超导体（HTSC）薄膜中涡流的静态和动态特性，这些薄膜具有前所未有的密度、复杂性和最小尺寸的钉钉点。理论上提出的非常规临界状态，钉钉势与缺陷尺寸的关系，人工钉钉阵列中的涡流熔化和横向霍尔可通约性效应将被研究。对通量操纵的探索，可能对设备有用，包括高速涡动力学，复杂钉住结构和涡棘轮效应的研究。虽然HTSCs复杂的晶体结构对其技术可用性构成了挑战，但该项目将把这种易感性转化为一种资产，以前所未有的分辨率制造超导纳米结构。在HTSCs中，点缺陷是由中等能量的氦离子辐照产生的，容易抑制临界温度。利用宽视场离子束通过模板掩模或He离子显微镜（HIM）聚焦光束的阴影投影，可以在HTSCs中绘制纳米尺度的钉钉景观。它们将通过各种实验得到进一步的研究。通过在HIM中辐照在htsc中产生超密集的钉钉晶格是一种新技术，最近由申请人首次展示。它允许探索一个迄今为止难以达到的尺寸和参数范围强通量耦合在人工钉钉晶格与晶格常数远低于伦敦穿透深度。这些实验将测试HTSCs中与通量相关的纳米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功能材料和超快、低耗散超导电路的开发具有重要意义。这可能会导致基于铜超导体的超小型磁场传感器（squid）的改进。这项研究将由三个具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（林茨约翰内斯·开普勒大学）和D. Kölle （Eberhard Karls Universität tbingen）。外部合作者将为该项目提供涡旋排列和涡旋动力学的分子动力学模拟（V. Misko，安特卫普大学）和涡旋可视化的本地探针技术（H. Suderow, universsidad Autónoma de Madrid）。

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).