scholarly journals Approaching the ultimate superconducting properties of (Ba,K)Fe2As2 by naturally formed low-angle grain boundary networks

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Kazumasa Iida ◽  
Dongyi Qin ◽  
Chiara Tarantini ◽  
Takafumi Hatano ◽  
Chao Wang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ion Irradiation ◽  
Microstructural Analysis ◽  
Grain Boundary Engineering ◽  
Superconducting Properties ◽  
Columnar Grains ◽  
Strong Pinning

AbstractThe most effective way to enhance the dissipation-free supercurrent in the presence of a magnetic field for type II superconductors is to introduce defects that act as artificial pinning centers (APCs) for vortices. For instance, the in-field critical current density of doped BaFe2As2 (Ba122), one of the most technologically important Fe-based superconductors, has been improved over the last decade by APCs created by ion irradiation. The technique of ion irradiation has been commonly implemented to determine the ultimate superconducting properties. However, this method is rather complicated and expensive. Here, we report a surprisingly high critical current density and strong pinning efficiency close to the crystallographic c-axis for a K-doped Ba122 epitaxial thin film without APCs, achieving performance comparable to ion-irradiated K-doped Ba122 single crystals. Microstructural analysis reveals that the film is composed of columnar grains with widths of approximately 30–60 nm. The grains are rotated around the b- (or a-) axis by 1.5° and around the c-axis by −1°, resulting in the formation of low-angle grain boundary networks. This study demonstrates that the upper limit of in-field properties reached in ion-irradiated K-doped Ba122 is achievable by grain boundary engineering, which is a simple and industrially scalable manner.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Effect of ZnO Nano-Oxide Addition on the Superconducting Properties of the (Bi.Pb)2223 Phase

2011 ◽  
Vol 324 ◽  
pp. 241-244 ◽  
Author(s):  
R. Mawassi ◽  
R. Awad ◽  
Mohamad Roumie ◽  
M. Kork ◽  
I. Hassan
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
High Temperature Superconductors ◽  
Weak Links ◽  
Superconducting Properties ◽  
X Ray ◽  
Weight Percentage ◽  
Nano Oxide

The major limitation of Bi-system superconductor applications is the intergrain weak links and weak flux pinning capability producing low critical current density of the Bibased phases. In order to enhance these characteristics and other superconducting properties, effective flux pinning centers are introduced into high temperature superconductors. In this work, different weight percentages of ZnO nano oxide were introduced at the final stage of the Bi1.8Pb0.4Sr2Ca2Cu3O10-y superconductor preparation process. Phase characterization was completed by X-ray diffraction (XRD). Exact constitution of the samples was determined using particle induced X-ray emission (PIXE). Granular and microstructure were investigated using scanning electron microscopy (SEM). Electrical resistivity as function of the temperature was carried to evaluate the relative performance of samples, and finally, E-J characteristic curves were obtained at 77K. Using 0.4 ZnO weight percentage, the electrical and granular properties were greatly enhanced, indicating more efficient pinning mechanisms. A critical current density of 949 A/cm2 was obtained which represents more than twice the value obtained for the pure sample (Jc= 445 A/cm2).

YBCO Bulk Superconductors with Sm Addition

2017 ◽  
Vol 891 ◽  
pp. 483-488 ◽  
Author(s):  
Daniela Volochová ◽  
Vitaliy Antal ◽  
Jozef Kováč ◽  
Pavel Diko
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Properties ◽  
Ybco Bulk ◽  
Pinning Centers ◽  
Bulk Superconductors ◽  
Powder Addition ◽  
Current Densities ◽  
Precursor Powders

The influence of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Precursor powders YBa2Cu3O7-δ (Y-123), Y2O3 and CeO2 were enriched with different amounts of SmBa2Cu3Oy (Sm-123) or Sm2O3 powders with the aim to increase critical current density, Jc,by introducing additional pinning centers. YBCO bulk superconductors with SmBa2Cu3Oy (Y123-Sm) or Sm2O3 (Y123-SmO) powder addition were prepared by the optimized top seeded melt growth process in the form of single grains. Microstructure analysis revealed that Sm2O3 addition leads to a higher amount of smaller Y2BaCuO5 (Y-211) particles, what is related to high critical current densities (Jc ~ 7 x 104 A/cm2) of the YBCO samples with Sm2O3 addition in low magnetic fields. The effect of Sm addition in the form of SmBa2Cu3Oy as well as Sm2O3 powder on Y2BaCuO5 particle size, critical temperature, Tc, and critical current density, Jc, is reported.

Increased grain boundary critical current density Jcgb by Pr-doping in pulsed laser–deposited Y1−xPrxBCO thin films

2011 ◽  
Vol 110 (11) ◽  
pp. 113905 ◽  
Author(s):  
M. Irjala ◽  
H. Huhtinen ◽  
V. P. S. Awana ◽  
M. Falter ◽  
P. Paturi
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Pulsed Laser

Porosity Effect on Superconducting Properties of YBa2Cu3Oδ and YCaBa4Cu6Oδ

2015 ◽  
Vol 1107 ◽  
pp. 601-605
Author(s):  
S.A. Senawi ◽  
H. Azhan ◽  
W.N.F.W. Zainal ◽  
W.A.W. Razali ◽  
A. Nazree ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Porous Structure ◽  
Critical Current ◽  
Current Density ◽  
Resistivity Measurement ◽  
Effective Cross Section ◽  
Ceramic Materials ◽  
Solid State Reaction Method ◽  
Superconducting Properties

This paper reports on the properties of YBa2Cu3Od (Y123) and YCaBa4Cu6Oy (Y146) with non-porous and porous structures. The relationship between calcium doping and critical temperature (Tc) was studied to determine the optimal superconducting properties. A series of heating and grinding via solid state reaction method was used to fabricate the ceramic materials. The electrical properties were investigated via critical temperature, TC and critical current density, JC using the resistivity measurement system (RMS). Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) were used to analyze the material morphology and structure, respectively. The orthorhombicity increased due to less porosity of the samples. The calcium presence partially replaced larger Ba(II) site and degraded orthorhombicity. The highest critical current density (JC) was porous YCaBa2Cu3Oy which was 2.32 A/cm2 compared to 0.75 A/cm2 for porous YCaBa4Cu6Oy at 60 K. The critical temperature for porous structure was less than non porous structure for Ca doped Y146 system which was 69.9 K and 67.9 K. SEM micrograph unveiled that the Jc was induced significantly by continuity of grain formation via grain size. Pores homogenized the grains surface quality and connectivity due to strain release thus increasing effective cross section of the sample for current density (Jc) over the vast areas.

Grain Boundary Structure and Properties of High-Tc Superconductors

1992 ◽  
Vol 275 ◽  
Author(s):  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Boundary Effects ◽  
Boundary Structure ◽  
Excess Charge ◽  
High Tc Superconductors ◽  
High Tc ◽  
Grain Boundary Structure

ABSTRACTWe have modelled the grain boundaries in high-Tc superconducting oxides and determined the critical current density. The tunneling of superconducting pairs across the coalesced regions is used to determine the boundary effects. The length of the coalesced regions, with continuity of the Cu-O planes maintained by relaxation of the atom positions, is determined by minimization of the energy of the configuration. The depression of the order parameter is evaluated using the continuity conditions at the boundary in the proximity effect formulation. The excess charge distribution at the core of the boundary, determined from the solution to the Poisson's equation, is used to determine the scattering of the superconducting pairs. The width of the boundary, evaluated from modelling, determines the transmission coefficient for tunnelingof superconducting pairs. The critical current density is expressed in terms of these four important factors associated with the grain boundary. All the experimental results are explained by the present modelling of the grain boundary effects.

Sign in / Sign up

Export Citation Format

Share Document