scholarly journals High-temperature superconductivity at the lanthanum cuprate/lanthanum–strontium nickelate interface

Nanoscale ◽  
2018 ◽  
Vol 10 (18) ◽  
pp. 8712-8720 ◽  
Author(s):  
F. Baiutti ◽  
G. Gregori ◽  
Y. E. Suyolcu ◽  
Y. Wang ◽  
G. Cristiani ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
Superconducting Layer ◽  
High Temperature Superconducting ◽  
Lanthanum Cuprate ◽  
Lanthanum Strontium ◽  
Lanthanum Nickelate

Local ionic and electronic redistribution occurs at the lanthanum cuprate/lanthanum nickelate epitaxial contact and gives rise to a high-temperature superconducting layer.

scholarly journals Imaging of Strong Nanoscale Vortex Pinning in GdBaCuO High-Temperature Superconducting Tapes

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1082
Author(s):  
David Collomb ◽  
Min Zhang ◽  
Weijia Yuan ◽  
Simon J. Bending
Keyword(s):  
High Temperature ◽  
Critical Current ◽  
Critical State ◽  
Vortex Pinning ◽  
Superconducting Film ◽  
Second Phase ◽  
Hall Probe ◽  
Superconducting Layer ◽  
High Temperature Superconducting ◽  
Magnetic Imaging

The high critical current density of second-generation high-temperature superconducting (2G-HTS) tapes is the result of the systematic optimisation of the pinning landscape for superconducting vortices through careful engineering of the size and density of defects and non-superconducting second phases. Here, we use scanning Hall probe microscopy to conduct a vortex-resolved study of commercial GdBaCuO tapes in low fields for the first time and complement this work with “local” magnetisation and transport measurements. Magnetic imaging reveals highly disordered vortex patterns reflecting the presence of strong pinning from a dense distribution of nanoscale Gd2O3 second-phase inclusions in the superconducting film. However, we find that the measured vortex profiles are unexpectedly broad, with full-width-half-maxima typically of 6 μm, and exhibit almost no temperature dependence in the range 10–85 K. Since the lateral displacements of pinned vortex cores are not expected to exceed the superconducting layer thickness, this suggests that the observed broadening is caused by the disruption of the circulating supercurrents due to the high density of nanoscale pinning sites. Deviations of our local magnetisation data from an accepted 2D Bean critical state model also indicate that critical state profiles relax quite rapidly by flux creep. Our measurements provide important information about the role second-phase defects play in enhancing the critical current in these tapes and demonstrate the power of magnetic imaging as a complementary tool in the optimisation of vortex pinning phenomena in 2G-HTS tapes.

scholarly journals Сверхпроводимость, инициированная электрическим полем в высокотемпературном сверхпроводнике при T>T-=SUB=-c-=/SUB=-

2020 ◽  
Vol 62 (8) ◽  
pp. 1154
Author(s):  
М.А. Кожушнер ◽  
В.С. Посвянский ◽  
Б.В. Лидский ◽  
В.Л. Боднева ◽  
Л.И. Трахтенберг
Keyword(s):  
High Temperature ◽  
Electric Field ◽  
High Temperature Superconductor ◽  
Hole Concentration ◽  
Two Dimensional ◽  
Superconducting Layer ◽  
Near Surface ◽  
Lanthanum Strontium ◽  
Occurrence Of Superconductivity ◽  
Lanthanum Strontium Cuprate

Abstract The theory of occurrence of superconductivity in the plate of high-temperature superconductor under electric field vertical to it, when the carrier concentration lies outside of the region of existence of superconductivity at the temperature T < $$T_{{\text{c}}}^{{\max }}$$ , was developed. The calculation was carried out for the layer of lanthanum strontium cuprate under the fields of 10^–1 V/nm ≥ E ≥ 10^–2 V/nm at various temperatures and hole concentrations. It was demonstrated that the quasi-two-dimensional superconducting layer of several Angstrom in thickness occurs near surface of the plate, moreover thickness of this layer does not depend on magnitude of the field, and depends only on temperature and on hole concentration.

Phenomenological Constraints on Theories for High Temperature Superconductivity

1989 ◽  
Vol 03 (12) ◽  
pp. 2083-2118 ◽  
Author(s):  
C.M. Varma
Keyword(s):  
High Temperature ◽  
Normal State ◽  
High Temperature Superconductivity ◽  
Superconducting Materials ◽  
Microscopic Model ◽  
High Temperature Superconducting ◽  
Spin Polarizability ◽  
Superconductive State

This is an attempt at a coherent view of the normal and superconductive state properties of the high-temperature superconducting materials. The discussion is organized as follows: Phenomenology of the Normal state anomalies, where it is shown that a single hypothesis about the charge and spin polarizability is enough to understand essentially all their properties. Phenomenology of the Superconductive state. Lessons from the Phenomenology. Phenomenology for the choice of a Microscopic Model. Comparison of the Bi-O family with the Cu-O family. Speculations on the Physics of the Magic Polarizability.

scholarly journals Study on the Applicability of Neutron Radiation Damage Method Used for High-Temperature Superconducting Tape Based on Geant4 and SRIM

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ying Zheng ◽  
Jinxing Zheng ◽  
Xudong Wang
Keyword(s):  
High Temperature ◽  
Radiation Damage ◽  
Cross Sections ◽  
Neutron Radiation ◽  
Superconducting Magnet ◽  
High Energy ◽  
Incident Neutron ◽  
Superconducting Layer ◽  
Superconducting Tape ◽  
High Temperature Superconducting

High-temperature superconducting material is a promising candidate to fabricate superconducting magnet for magnetic confinement fusion reactors. The DPA number of the 1 µm thick superconducting layer in a high temperature superconducting tape under neutron irradiation needs to be calculated to predict the property changes. The DPA cross sections, which ignore the spatial distribution of vacancies caused by PKAs, are commonly used to obtain the results of the damage energy and DPA. However, for geometric models with the thickness as small as 1 µm, the energy and angular distribution of PKAs reveal that a significant number of PKAs with relatively high energy tend to scatter forward and cross the boundary of model, so the thickness of model has the potential to affect the number of displaced atoms. In this paper, we developed a method based on Geant4 and SRIM to evaluate the deviation of the traditional analytic method caused by the thickness. Geant4 is used to obtain the location, direction, and energy of PKAs, while SRIM is used to track every PKA and obtain damage energy and the number of displaced atoms. The radiation damage calculation of simple thin plate models with different thicknesses and the tape model are conducted with the neutron energies from 1 to 14 MeV. The results show that PKAs need to be tracked continuously for models with thickness less than 10 µm and the deviation of the analytic formulas increases rapidly with the decrease of thickness. For the superconducting layer composed of four different elements in the tape, the deviation also depends on the proportion of each atomic species and the neutron-atom interaction cross sections under different incident neutron energy.

scholarly journals Increase in Critical Current Density for Increasing Applied Magnetic Field in a High-Temperature Superconducting Superlattice

2018 ◽  
Author(s):  
Shinichi Ishiguri ◽  
Shotaro Tawara
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Applied Magnetic Field ◽  
Stationary Wave ◽  
Superconducting Layer ◽  
High Temperature Superconducting ◽  
Insulator Layers

In the present work, a superlattice structure comprising superconducting and insulator layers is studied. Here, if a magnetic field is applied parallel to the layers, the lack of a pinning center leads to a novel transition; in particular, as the applied magnetic field is reduced, the stationary wave surrounding the magnetic flux quantum in the superconducting layer eventually collides with the superconducting&ndash;insulating interfaces on both sides because its radius becomes larger than the width of the superconducting layer. At this instant, the stationary wave will collapse, and a transition will occur: the magnetic quanta are collapsed and thus the uniform magnetic field distribution is achieved, which corresponds to the transition from the superconducting state to the normal state over critical current. Considering a one-dimensional model of the structure, a critical current density equation is derived that indicates an increase in the critical current density for increased applied magnetic field. Subsequently, the same calculation was conducted after changing the direction of the magnetic field component, and the combination of these two calculations expresses the anisotropic property of the structure. The phenomenon is also predicted for anisotropic critical current density. This phenomenon is an important discovery that helps manufacture high-temperature superconducting tape as well as large high-temperature superconducting coils.

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