Engineering of superconductors and superconducting devices using artificial pinning sites

Abstract Vortex matter in superconducting films and devices is not only an interesting topic for basic research but plays a substantial role in the applications of superconductivity in general. We demonstrate, that in most electronic applications, magnetic flux penetrates the superconductor and affects the performance of superconducting devices. Therefore, vortex manipulation turns out to be a useful tool to avoid degradation of superconducting device properties. Moreover, it can also be used to analyze and understand novel and interesting physical properties and develop new concepts for superconductor applications. In this review, various concepts for vortex manipulation are sketched. For example, the use of micro- and nanopatterns (especially, antidots) for guiding and trapping of vortices in superconducting films and thin film devices is discussed and experimental evidence of their vortex guidance and vortex trapping by various arrangements of antidots is given. We demonstrate, that the vortex state of matter is very important in applications of superconductivity. A better understanding does not only lead to an improvement of the performance of superconductor components, such as reduced noise, better power handling capability, or improved reliability, it also promises deeper insight into the basic physics of vortices and vortex matter.

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Three-dimensional spatially resolved neutron diffraction from a disordered vortex lattice

Journal of Applied Crystallography ◽

10.1107/s0021889811006790 ◽

2011 ◽

Vol 44 (2) ◽

pp. 414-417

Author(s):

Xi Wang ◽

Helen A. Hanson ◽

Xinsheng Sean Ling ◽

Charles F. Majkrzak ◽

Brian B. Maranville

Keyword(s):

Neutron Diffraction ◽

Vortex Lattice ◽

Three Dimensional ◽

Vortex State ◽

Prototype System ◽

Vortex Matter ◽

Atomic Lattice ◽

Spatially Resolved ◽

Neutron Diffraction Technique ◽

Vortex Physics

The vortex matter in bulk type II superconductors serves as a prototype system for studying the random pinning problem in condensed matter physics. Since the vortex lattice is embedded in an atomic lattice, small-angle neutron scattering (SANS) is the only technique that allows for direct structural studies. In traditional SANS methods, the scattering intensity is a measure of the structure factor averaged over the entire sample. Recent studies in vortex physics have shown that it is highly desirable to develop a SANS technique that is capable of resolving the spatial inhomogeneities in the bulk vortex state. This article reports a novel slicing neutron diffraction technique using atypical collimation and an areal detector, which allows for observing the three-dimensional disorder of the vortex matter inside an as-grown Nb single crystal.

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The Oxford Handbook of Small Superconductors

10.1093/oxfordhb/9780198738169.001.0001 ◽

2017 ◽

Cited By ~ 5

Keyword(s):

Quantum Wires ◽

Superconducting Devices ◽

Basic Research ◽

Spectroscopic Studies ◽

Current Status ◽

Great Promise ◽

Surface And Interface ◽

Technological Advances ◽

Mesoscopic Superconductors ◽

Low Dimensional

This handbook examines cutting-edge developments in research and applications of small or mesoscopic superconductors, offering a glimpse of what might emerge as a giga world of nano superconductors. Contributors, who are eminent frontrunners in the field, share their insights on the current status and great promise of small superconductors in the theoretical, experimental, and technological spheres. They discuss the novel and intriguing features and theoretical underpinnings of the phenomenon of mesoscopic superconductivity, the latest fabrication methods and characterization tools, and the opportunities and challenges associated with technological advances. The book is organized into three parts. Part I deals with developments in basic research of small superconductors, including local-scale spectroscopic studies of vortex organization in such materials, Andreev reflection and related studies in low-dimensional superconducting systems, and research on surface and interface superconductivity. Part II covers the materials aspects of small superconductors, including mesoscopic effects in superconductor–ferromagnet hybrids, micromagnetic measurements on electrochemically grown mesoscopic superconductors, and magnetic flux avalanches in superconducting films with mesoscopic artificial patterns. Part III reviews the current progress in the device technology of small superconductors, focusing on superconducting spintronics and devices, barriers in Josephson junctions, hybrid superconducting devices based on quantum wires, superconducting nanodevices, superconducting quantum bits of information, and the use of nanoSQUIDs in the investigation of small magnetic systems.

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A 21st Century perspective on the contributions of Michaelis to enzyme kinetics

The Biochemist ◽

10.1042/bio03402047 ◽

2012 ◽

Vol 34 (2) ◽

pp. 47-50

Author(s):

Herbert Gutfreund

Keyword(s):

World War I ◽

Enzyme Kinetics ◽

Biological Systems ◽

Basic Research ◽

Hydrogen Ions ◽

Medical Studies ◽

World War ◽

Medical Work ◽

Basic Physics ◽

Paul Ehrlich

Leonor Michaelis (1875–1949) made some of the most important contributions to the application of physical chemistry to biological systems during the first half of the 20th Century. Like many young men interested in using basic physics and chemistry to study biomedical problems at that time, Michaelis was advised by no less a person than Paul Ehrlich to qualify in medicine to be able to earn a living. He followed that advice, and the work I am concerned with here was carried out after he completed his medical studies. For about 5 years before the outbreak of World War I, Michaelis's principal research interests centred on enzyme kinetics and the importance of hydrogen ions in biological systems. He carried out his basic research in clinical laboratories side by side with his medical work.

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MEASURING AMPLITUDE AND FREQUENCY CHARACTERISTICS OF KINETIC INDUCTANCE IN SUPERCONDUCTING FILMS

Izvestia Ufimskogo Nauchnogo Tsentra RAN ◽

10.31040/2222-8349-2021-0-1-106-110 ◽

2021 ◽

Vol 0 (1) ◽

pp. 106-110

Author(s):

K.V. SHEIN ◽

◽

K.YU. ARUTYUNOV ◽

V.V. ZAVIALOV ◽

◽

...

Keyword(s):

Resonant Frequency ◽

High Frequency ◽

Response Rate ◽

Basic Research ◽

Superconducting Films ◽

Niobium Nitride ◽

Kinetic Inductance ◽

Superconducting Detectors ◽

Lc Circuit ◽

On Chip

This research was performed using thin superconducting strips in the shape of tightly packed meanders made of niobium nitride (NbN) ultrathin superconducting strips about 100 nm wide, 5 nm thick and up to 100 µm long. The structures revealed the effect of high kinetic inductance at temperatures lower than the critical temperature. Consideration was given to the temperature dependence of LC-circuit resonant frequency where a highlyinductive superconducting meander was used as a source of L inductance and а chip capacitor as a source of C capacitance. Experimental data point to the fact that kinetic inductance depends on temperature, since there was a shift in the resonant frequency at temperatures lower than the critical one relative to the normal state. This is indicative to the fact that in such systems impedance is changed due to growing kinetic inductance during the transition to the superconducting state. This effect is of relevance both in applied and basic research. When using different superconducting detectors, kinetic inductance can exert a distinct effect on their response rate. In basic research developments, where the on-chip implementation of charge (current) stabilization is required, high frequency impedance of connecting circuits is very useful.

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Conductance asymmetries in mesoscopic superconducting devices due to finite bias

SciPost Physics ◽

10.21468/scipostphys.10.2.037 ◽

2021 ◽

Vol 10 (2) ◽

Author(s):

André Melo ◽

Chun-Xiao Liu ◽

Piotr Rożek ◽

Tómas Örn Rosdahl ◽

Michael Wimmer

Keyword(s):

Bound States ◽

Voltage Dependence ◽

Superconducting Devices ◽

Scattering Matrix ◽

Tunnel Barrier ◽

Tunneling Conductance ◽

Physical Origin ◽

Andreev Bound States ◽

Superconducting Device ◽

Symmetry Relations

Tunneling conductance spectroscopy in normal metal-superconductor junctions is an important tool for probing Andreev bound states in mesoscopic superconducting devices, such as Majorana nanowires. In an ideal superconducting device, the subgap conductance obeys specific symmetry relations, due to particle-hole symmetry and unitarity of the scattering matrix. However, experimental data often exhibits deviations from these symmetries or even their explicit breakdown. In this work, we identify a mechanism that leads to conductance asymmetries without quasiparticle poisoning. In particular, we investigate the effects of finite bias and include the voltage dependence in the tunnel barrier transparency, finding significant conductance asymmetries for realistic device parameters. It is important to identify the physical origin of conductance asymmetries: in contrast to other possible mechanisms such as quasiparticle poisoning, finite-bias effects are not detrimental to the performance of a topological qubit. To that end we identify features that can be used to experimentally determine whether finite-bias effects are the source of conductance asymmetries.

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Flow Noise of Driven Vortex Matter in Amorphous Superconducting Films

10.1063/1.3140566 ◽

2009 ◽

Author(s):

S. Okuma ◽

Y. Suzuki ◽

N. Kokubo ◽

Massimo Macucci ◽

Giovanni Basso

Keyword(s):

Superconducting Films ◽

Vortex Matter ◽

Flow Noise

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Elliptic-disc filters of high-T/sub c/ superconducting films for power-handling capability over 100 W

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/22.853469 ◽

2000 ◽

Vol 48 (7) ◽

pp. 1256-1264 ◽

Cited By ~ 33

Author(s):

K. Setsune ◽

A. Enokihara

Keyword(s):

Superconducting Films ◽

Power Handling ◽

Power Handling Capability

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Modelling Strengthening Mechanisms in Solids Using Dislocation Dynamics

Materials ◽

10.1115/imece2003-43180 ◽

2003 ◽

Author(s):

Tariq A. Khraishi ◽

Lincan Yan ◽

Yu-Lin Shen

Keyword(s):

Basic Research ◽

Theoretical Models ◽

Dislocation Dynamics ◽

Crystalline Solid ◽

Strengthening Effect ◽

Structure Property ◽

Simulation Methodology ◽

Structure Property Relationships ◽

Basic Physics ◽

Experimental Findings

The mechanical properties of crystalline solids are inherently a function of their microstructure which in turn is governed by processing of the material. Although advances in understanding the structure-property relationships have been achieved, more basic research to expand the knowledge base is certainly needed. Recent work on exploring the strengthening effect of particles and grain-boundaries in a crystalline solid, using the fundamental approach of dislocation dynamics, is presented. Whenever appropriate, comparisons to experimental findings or theoretical models are made. The work demonstrates the power and limitations of such simulation methodology. In particular some basic physics of the interaction between dislocations and these microstructural features are revealed.

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