Superconductivity in Nanosystems

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Synthesis, Interfaces and Nanostructures".

Deadline for manuscript submissions: closed (31 October 2022) | Viewed by 12778

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Guest Editor
Quantum Materials and Photonics Research Group QMatterPhotonics, Department of Particle Physics, University of Santiago de Compostela, ES-15782 Santiago de Compostela, Spain
Interests: superconducting devices; photodetectors; nanostructured materials; nanostructured and microstructured superconductors; high temperature superconductors
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Special Issue Information

Dear Colleagues,

The interplay between nanoscience and superconductivity is increasingly attracting mainstream interest, not only as a very fruitful route for the discovery of new fundamental phenomenology, but also as a way to achieve quantum coherence at a device scale, as required in emerging applications such as, for instance, quantum computing.

This Special Issue of "Nanomaterials" aims to cover the most recent research in superconducting nanomaterials or nanosystems. Specific topics include, but are not limited to, the following:

Fabrication and/or measurement of novel superconducting nanosystems, such as:

  • nanosized superconductors: nanowires, nanogranular systems
  • superconducting thin films, bidimensional or nano-layered systems
  • hybrid superconducting-nonsuperconducting nanointerfacing systems
  • micro- or nano-patterned nanostructured superconductors, etc.

Studies of the effects induced by reduced dimensionality over the superconducting characteristics, such as:

  • critical temperature and magnetic fields
  • vortex pinning and matching
  • superconducting fluctuations
  • emergence of topological or other novel quantum states, etc.

Development of superconducting nanosystems for quantum technologies, such as:

  • photon detection, bolometers and/or resonant devices,
  • qubit or quantum information devices based on Josephson junctions, quantum dots, or other superconducting nanosystems, etc.

Dr. M.V. Ramallo
Guest Editor

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Keywords

  • superconducting nanosystems
  • nanostructured superconductors
  • hybrid superconducting nanosystems
  • thin film and layered superconductors
  • superconducting nanodevices
  • qubit superconducting nanodevices
  • Josephson junctions
  • superconducting quantum dots
  • topological and reduced dimensionality superconductors
  • two-dimensional superconductors

Published Papers (7 papers)

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Editorial

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3 pages, 188 KiB  
Editorial
Superconductivity in Nanosystems: A Fruitful Path to New Phenomenology in Quantum Materials
by Manuel V. Ramallo
Nanomaterials 2023, 13(3), 592; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13030592 - 01 Feb 2023
Viewed by 927
Abstract
In the recent years, the landscape of the research in superconductivity has experienced a progressive focus on varied superconducting systems, which share as common primary characteristics the reduction of some of their dimensionalities and the emergence of qualitatively novel phenomenology with respect to [...] Read more.
In the recent years, the landscape of the research in superconductivity has experienced a progressive focus on varied superconducting systems, which share as common primary characteristics the reduction of some of their dimensionalities and the emergence of qualitatively novel phenomenology with respect to bulk superconducting materials [...] Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)

Research

Jump to: Editorial

17 pages, 1208 KiB  
Article
A Scenario for the Critical Fluctuations near the Transition of Few-Bilayer Films of High-Temperature Cuprate Superconductors
by Martín M. Botana and Manuel V. Ramallo
Nanomaterials 2022, 12(24), 4368; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12244368 - 07 Dec 2022
Cited by 1 | Viewed by 1059
Abstract
We study the critical fluctuations near the resistive transition of very thin films of high-temperature cuprate superconductors composed of a number N of only a few unit cells of superconducting bilayers. For that, we solve the fluctuation spectrum of a Gaussian–Ginzburg–Landau model for [...] Read more.
We study the critical fluctuations near the resistive transition of very thin films of high-temperature cuprate superconductors composed of a number N of only a few unit cells of superconducting bilayers. For that, we solve the fluctuation spectrum of a Gaussian–Ginzburg–Landau model for few-bilayers superconductors considering two alternating Josephson interlayer interaction strengths, and we obtain the corresponding paraconductivity above the transition. Then, we extend these calculations to temperatures below the transition through expressions for the Ginzburg number and Kosterlitz–Thouless-like critical region. When compared with previously available data in YBa2Cu3O7δ few-bilayers systems, with N = 1 to 4, our results seem to provide a plausible scenario for their critical regime. Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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9 pages, 1944 KiB  
Article
High-Quality Ferromagnetic Josephson Junctions Based on Aluminum Electrodes
by Antonio Vettoliere, Roberta Satariano, Raffaella Ferraiuolo, Luigi Di Palma, Halima Giovanna Ahmad, Giovanni Ausanio, Giovanni Piero Pepe, Francesco Tafuri, Davide Massarotti, Domenico Montemurro, Carmine Granata and Loredana Parlato
Nanomaterials 2022, 12(23), 4155; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12234155 - 24 Nov 2022
Cited by 6 | Viewed by 1884
Abstract
Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and [...] Read more.
Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and spintronics. In this paper, we report on the fabrication and characterization of high-quality ferromagnetic Josephson junctions based on aluminum technology. We employed an innovative fabrication process inspired by niobium-based technology, allowing us to obtain very high-quality hybrid aluminum Josephson junctions; thus, supporting the use of ferromagnetic Josephson junctions in advanced quantum circuits. The fabrication process is described in detail and the main DC transport properties at low temperatures (current–voltage characteristic, critical current as a function of the temperature, and the external magnetic field) are reported. Here, we illustrate in detail the fabrication process, as well as the main DC transport properties at low temperatures (current–voltage characteristic, critical current as a function of the temperature, and the external magnetic field). Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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10 pages, 826 KiB  
Article
Ordered Bose Glass of Vortices in Superconducting YBa2Cu3O7−δ Thin Films with a Periodic Pin Lattice Created by Focused Helium Ion Irradiation
by Lucas Backmeister, Bernd Aichner, Max Karrer, Katja Wurster, Reinhold Kleiner, Edward Goldobin, Dieter Koelle and Wolfgang Lang
Nanomaterials 2022, 12(19), 3491; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12193491 - 06 Oct 2022
Cited by 7 | Viewed by 1495
Abstract
The defect-rich morphology of YBa2Cu3O7−δ (YBCO) thin films leads to a glass-like arrangement of Abrikosov vortices which causes the resistance to disappear in vanishing current densities. This vortex glass consists of entangled vortex lines and is identified [...] Read more.
The defect-rich morphology of YBa2Cu3O7−δ (YBCO) thin films leads to a glass-like arrangement of Abrikosov vortices which causes the resistance to disappear in vanishing current densities. This vortex glass consists of entangled vortex lines and is identified by a characteristic scaling of the voltage–current isotherms. Randomly distributed columnar defects stratify the vortex lines and lead to a Bose glass. Here, we report on the observation of an ordered Bose glass in a YBCO thin film with a hexagonal array of columnar defects with 30 nm spacings. The periodic pinning landscape was engineered by a focused beam of 30 keV He+ ions in a helium-ion microscope. Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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13 pages, 9234 KiB  
Article
Effect of Impurity Scattering on Percolation of Bosonic Islands and Superconductivity in Fe Implanted NbN Thin Films
by Rajdeep Adhikari, Bogdan Faina, Verena Ney, Julia Vorhauer, Antonia Sterrer, Andreas Ney and Alberta Bonanni
Nanomaterials 2022, 12(18), 3105; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12183105 - 07 Sep 2022
Cited by 3 | Viewed by 1550
Abstract
A reentrant temperature dependence of the thermoresistivity ρxx(T) between an onset local superconducting ordering temperature Tloconset and a global superconducting transition at T=Tglooffset has been reported in disordered conventional 3-dimensional (3D) superconductors. The [...] Read more.
A reentrant temperature dependence of the thermoresistivity ρxx(T) between an onset local superconducting ordering temperature Tloconset and a global superconducting transition at T=Tglooffset has been reported in disordered conventional 3-dimensional (3D) superconductors. The disorder of these superconductors is a result of either an extrinsic granularity due to grain boundaries, or of an intrinsic granularity ascribable to the electronic disorder originating from impurity dopants. Here, the effects of Fe doping on the electronic properties of sputtered NbN layers with a nominal thickness of 100 nm are studied by means of low-T/high-μ0H magnetotransport measurements. The doping of NbN is achieved via implantation of 35 keV Fe ions. In the as-grown NbN films, a local onset of superconductivity at Tloconset=15.72K is found, while the global superconducting ordering is achieved at Tglooffset=15.05K, with a normal state resistivity ρxx=22μΩ·cm. Moreover, upon Fe doping of NbN, ρxx=40μΩ·cm is estimated, while Tloconset and Tglooffset are measured to be 15.1 K and 13.5 K, respectively. In Fe:NbN, the intrinsic granularity leads to the emergence of a bosonic insulator state and the normal-metal-to-superconductor transition is accompanied by six different electronic phases characterized by a N-shaped T dependence of ρxx(T). The bosonic insulator state in a s-wave conventional superconductor doped with dilute magnetic impurities is predicted to represent a workbench for emergent phenomena, such as gapless superconductivity, triplet Cooper pairings and topological odd frequency superconductivity. Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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14 pages, 3843 KiB  
Article
Pinning Potential of the Self-Assembled Artificial Pinning Centers in Nanostructured YBa2Cu3O7−x Superconducting Films
by Ion Ivan, Alina M. Ionescu, Daniel N. Crisan, Andreea Andrei, Armando Galluzzi, Massimiliano Polichetti, Jesus Mosqueira and Adrian Crisan
Nanomaterials 2022, 12(10), 1713; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12101713 - 17 May 2022
Cited by 3 | Viewed by 1638
Abstract
For high-field power applications of high-temperature superconductors, it became obvious in recent years that nano-engineered artificial pinning centers are needed for increasing the critical current and pinning potential. As opposed to the artificial pinning centers obtained by irradiation with various particles, which is [...] Read more.
For high-field power applications of high-temperature superconductors, it became obvious in recent years that nano-engineered artificial pinning centers are needed for increasing the critical current and pinning potential. As opposed to the artificial pinning centers obtained by irradiation with various particles, which is a quite expensive approach, we have studied superconducting samples having self-assembled defects, created during the sample fabrication, that act as effective pinning centers. We introduced a simple, straight-forward method of estimating the frequency-dependent critical current density by using frequency-dependent AC susceptibility measurements, in fixed temperatures and DC magnetic fields, from the positions of the maxima in the dependence of the out-of-phase susceptibility on the amplitude of AC excitation magnetic field. The results are compatible with a model that stipulates a logarithmic dependence of the pinning potential on the probing current. A mathematical derivation allowed us to estimate from the experimental data the pinning potentials in various samples, and in various DC magnetic fields. The resulted values indicate large pinning potentials, leading to very small probability of magnetic flux escaping the pinning wells, hence, leading to very high critical currents in high magnetic fields. Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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10 pages, 2135 KiB  
Article
Observation of Cu Spin Fluctuations in High-Tc Cuprate Superconductor Nanoparticles Investigated by Muon Spin Relaxation
by Suci Winarsih, Faisal Budiman, Hirofumi Tanaka, Tadashi Adachi, Akihiro Koda, Yoichi Horibe, Budhy Kurniawan, Isao Watanabe and Risdiana Risdiana
Nanomaterials 2021, 11(12), 3450; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11123450 - 20 Dec 2021
Cited by 4 | Viewed by 3188
Abstract
The nano-size effects of high-Tc cuprate superconductor La2xSrxCuO4 with x = 0.20 are investigated using X-ray diffractometry, Transmission electron microscopy, and muon-spin relaxation (μSR). It is investigated whether an increase in the [...] Read more.
The nano-size effects of high-Tc cuprate superconductor La2xSrxCuO4 with x = 0.20 are investigated using X-ray diffractometry, Transmission electron microscopy, and muon-spin relaxation (μSR). It is investigated whether an increase in the bond distance of Cu and O atoms in the conducting layer compared to those of the bulk state might affect its physical and magnetic properties. The μSR measurements revealed the slowing down of Cu spin fluctuations in La2xSrxCuO4 nanoparticles, indicating the development of a magnetic correlation at low temperatures. The magnetic correlation strengthens as the particle size reduces. This significantly differs from those observed in the bulk form, which show a superconducting state below Tc. It is indicated that reducing the particle size of La2xSrxCuO4 down to nanometer size causes the appearance of magnetism. The magnetism enhances with decreasing particle size. Full article
(This article belongs to the Special Issue Superconductivity in Nanosystems)
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