scholarly journals Vortex phase transition and superconducting properties in quasi-two-dimensional k-(BEDT-TTF)2Cu[N(CN)2]Br organic superconductor

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
H. El Ouaddi ◽  
A. Tirbiyine ◽  
A. Taoufik ◽  
Y. Ait Ahmed ◽  
F. Chiban ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Vortex Lattice ◽  
Magnetic Hysteresis ◽  
Magnetic Behavior ◽  
Organic Superconductor ◽  
Shielding Effect ◽  
Superconducting Transition ◽  
Critical Current Density Jc

We report investigations of the low temperature dc susceptibility and the magnetization on the layered organic superconductor k-(BEDT-TTF)2Cu[N(CN)2]Br near 80 K and the effect of disorder on the superconducting transition temperature Tc. The shielding effect (S) and the critical current density Jc were studied (with H parallel to the c axis of the crystal). Jc can be estimated by analysis of magnetic hysteresis measurement using the Bean model. For each temperature value, we observed two regimes in the critical current density Jc(H). Our results show that the magnetic properties of these compounds depend strongly on the cooling rate. The structural transformation which occurs at the vicinity of 80 K very strongly influences the physics of vortex lattice and the associated magnetic behavior. #organic_superconductor #critical_current #shielding_effect #magnetic_susceptibility #vortex_pinning

MAGNETIZATION MEASUREMENTS IN THE 80 K TRANSFORMATION FOR DEUTERATED ORGANIC SUPERCONDUCTOR κ-(BEDT-TTF)2Cu[N(CN)2]Br

2013 ◽  
Vol 27 (05) ◽  
pp. 1350037 ◽  
Author(s):  
H. EL OUADDI ◽  
A. TIRBIYINE ◽  
A. TAOUFIK ◽  
A. RAMZI ◽  
A. HAFID ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Cooling Rate ◽  
Critical Current ◽  
Current Density ◽  
Vortex Lattice ◽  
Magnetic Measurements ◽  
Strong Dependence ◽  
Magnetic Behavior ◽  
Organic Superconductor ◽  
Irreversible Magnetization

In this paper, we report systematic magnetic measurements on deuterated organic superconductor (κ- D 8- Br )κ-( BEDT - TTF )2 Cu [ N ( CN )2] Br . The irreversibility line H irr (T) and the critical current density Jc were studied. Our results show the strong dependence of H irr (T) and Jc on the cooling rate. The structural transformation which occurs at the vicinity of 80 K very strongly influences the physics of vortex lattice and the associated magnetic behavior. The irreversible magnetization becomes null at H irr and vortices are not pinned; therefore they can displace more freely for an increase of the field or the temperature.

scholarly journals Effect of Pressure on the Superconducting Properties of Tl2Ba2Ca2Cu3O9-δ

Crystals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Anota Ijaduola ◽  
Rai Shipra ◽  
Athena Sefat
Keyword(s):  
Transition Temperature ◽  
Hydrostatic Pressure ◽  
Critical Current Density ◽  
Current Density ◽  
Magnetic Hysteresis ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Piston Cylinder ◽  
State Formula ◽  
Critical Current Density Jc

This study investigated the application of pressure on the superconducting properties of a thallium-based cuprate, namely Tl2Ba2Ca2Cu3O9-δ (Tl-2223). The superconducting transition temperature (Tc) and the critical current density (Jc) were studied by applying ~1 GPa of pressure. This hydrostatic pressure was applied in a piston-cylinder-cell (PCC), using Pb as a manometer and Daphne 7373 oil as the pressure transmitting medium. For estimating the Jc, we used Bean’s critical state formula on the magnetic hysteresis curves at 10 K and 20 K. Both the Tc and Jc improved with pressure. The Jc values increased at both temperatures and the Tc value increased by 4 K with a pressure of 0.8 GPa. These results clearly indicate that pressure is another tool to control properties of quantum materials.

scholarly journals Critical Current and Pinning Features of a CaKFe4As4 Polycrystalline Sample

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6611
Author(s):  
Armando Galluzzi ◽  
Antonio Leo ◽  
Andrea Masi ◽  
Francesca Varsano ◽  
Angela Nigro ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Hysteresis Loops ◽  
Magnetic Behavior ◽  
Polycrystalline Sample ◽  
Critical Parameters ◽  
Zero Field ◽  
Critical Current Density Jc ◽  
Field Cooling

We analyze the magnetic behavior of a CaKFe4As4 polycrystalline sample fabricated by a mechanochemically assisted synthesis route. By means of DC magnetization (M) measurements as a function of the temperature (T) and DC magnetic field (H) we study its critical parameters and pinning features. The critical temperature Tc has been evaluated by M(T) curves performed in Zero Field Cooling-Field Cooling conditions. These curves show the presence of a little magnetic background for temperatures above Tc, as also confirmed by the hysteresis loops M(H). Starting from the M(H) curves, the critical current density Jc of the sample has been calculated as a function of the field at different temperatures in the framework of the Bean critical state model. The Jc(H) values are in line with the ones reported in the literature for this typology of samples. By analyzing the temperature dependence of the critical current density Jc(T) at different magnetic fields, it has been found that the sample is characterized by a strong type pinning regime. This sample peculiarity can open perspectives for future improvement in the fabrication of this material.

High Pressure Synthesized Magnesium Diboride- and Dodecaboride-Based Superconductors: Structure and Properties

2010 ◽  
Vol 670 ◽  
pp. 21-27 ◽  
Author(s):  
Tatiana Prikhna ◽  
Wolfgang Gawalek ◽  
Yaroslav Savchuk ◽  
Athanasios G. Mamalis ◽  
Vasiliy Tkach ◽  
...  
Keyword(s):  
High Pressure ◽  
Transition Temperature ◽  
Critical Current Density ◽  
Current Density ◽  
Magnesium Diboride ◽  
Synthesis Temperature ◽  
Superconducting Transition ◽  
Structure And Properties ◽  
Synthesized Materials ◽  
Critical Current Density Jc

The critical current density, jc, of high-pressure synthesized MgB2-based balk materials correlates with the amount and distribution of higher borides (MgB12) and Mg-B-O inclusions, which in tern correlates with the synthesis temperature and presence of additions (Ti, Ta, SiC). High-pressure-synthesized materials with near MgB12 composition of matrix exhibited superconducting transition temperature, Tc, of about 37 K, rather high jc (5∙105 and 103 A/cm2 in 0 T and 3.5 T, respectively, at 20 K) and doubled matrix microhardness: 25±1.1 GPa at 4.9 N –load as compared to materials with MgB2).

Characterization of superconducting SmBa2Cu3O7 films grown by pulsed laser deposition

2002 ◽  
Vol 17 (10) ◽  
pp. 2599-2603 ◽  
Author(s):  
Q. X. Jia ◽  
S. R. Foltyn ◽  
J. Y. Coulter ◽  
J. F. Smith ◽  
M. P. Maley
Keyword(s):  
Transition Temperature ◽  
Critical Current Density ◽  
Pulsed Laser Deposition ◽  
Critical Current ◽  
Current Density ◽  
Deposition Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Superconducting Transition ◽  
Transition Width

We have investigated epitaxial superconducting SmBa2Cu3O7 (Sm123) films grown by pulsed-laser deposition on single-crystal SrTiO3 substrates. The deposition temperature plays an important role in determining the superconducting properties of Sm123 films. The superconducting transition temperature increases with the deposition temperature whereas the transition width decreases at deposition temperatures in the range of 700–875 °C. A Sm123 film deposited at 850 °C exhibits a transition temperature above 93 K with a transition width less than 0.5 K. Even though Sm123 films exhibit a higher transition temperature than Yba2Cu3O7 (Y123), the Sm123 shows lower critical current density at liquid-nitrogen temperature. The nominal critical current density of Sm123 film is less than 1 MA/cm2 at 75.4 K. Nevertheless, the Sm123 films have less anisotropy and stronger pinning characteristics compared to Y123. They are also much smoother with fewer particulates, as revealed by scanning electron microscopy.

Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals

2021 ◽  
Author(s):  
Yongqiang Pan ◽  
Nan Zhou ◽  
Bencheng Lin ◽  
Jinhua Wang ◽  
Zengwei Zhu ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Pinning Force ◽  
Magnetization Relaxation ◽  
Pinning Mechanism

Abstract Fe1+yTe0.6Se0.4 has considerable application potential due to its large critical current density (J c) and high upper critical magnetic field (H c2). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c ab /J c c ~ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities (F p) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p[F p/F p-max] versus the normalized field h[H/H c2]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe1+yTe0.6Se0.4 clean single crystals was confirmed to be normal point pinning.

Influence of deposition rate on the properties of thick YBa2Cu3O7–δ films

1997 ◽  
Vol 12 (11) ◽  
pp. 2941-2946 ◽  
Author(s):  
S. R. Foltyn ◽  
E. J. Peterson ◽  
J. Y. Coulter ◽  
P. N. Arendt ◽  
Q. X. Jia ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Deposition Rate ◽  
Current Density ◽  
Oxygen Deficiency ◽  
Lattice Parameter ◽  
High Rate ◽  
Superconducting Transition ◽  
And Performance ◽  
Low Rate

To investigate potential limits to the rate at which high-quality YBa2Cu3O7–δ can be deposited, we have produced a series of 1 μm thick films by pulsed laser deposition on single-crystal SrTiO3 substrates at average rates ranging from 2 Å/s to 240 Å/s. The critical current density of low-rate films was over 2 MA/cm2 at 75 K, self field, but dropped linearly with rate to about 1 MA/cm2 at the upper end of the range. In addition, the superconducting transition temperature, resistivity above the transition, and performance in an applied magnetic field were all degraded by increasing the deposition rate. A change in c-axis lattice parameter suggests that possible causes for this degradation are oxygen deficiency or cation disorder with the latter being the more likely. Annealing high-rate films at 790 °C for as little as 20 min improved critical current density to within 20% of low-rate values, and resulted in dramatic improvements in other film properties as well.

Studies on Development of MgB2 Superconductor with Improved In-Field Critical Current Density

2010 ◽  
Vol 117 ◽  
pp. 63-68 ◽  
Author(s):  
Krishnankutty Vinod ◽  
Syamaprasad Upendran
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Natural Material ◽  
Bulk Superconductor ◽  
Mgb2 Wires ◽  
Heating Method ◽  
Self Heating ◽  
Critical Current Density Jc ◽  
Powder In Tube

The present study focuses on the preparation of good quality MgB2 superconductor in bulk, wire/tape forms and on the improvement of in-field critical current density [JC(H)]. MgB2 bulk superconductor was prepared by a simple Powder-In-Sealed-Tube (PIST) method and MgB2 wires and tapes were prepared by the Powder-In-Tube (PIT) method. A novel electrical self-heating method was introduced for the preparation of Fe sheathed MgB2 wires and tapes. Burned Rice Husk (BRH), an inexpensive natural material is found to be one of the best additives for enhancing the in-field critical current density of MgB2. By selecting suitable combinations of additives a significant enhancement of the critical current density by 1-2 orders of magnitude were achieved for fields > 5 T, at 5-15 K.

Crystal Growth of High Temperature Superconductors

MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci
Keyword(s):  
High Temperature ◽  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Large Scale ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Theoretical Understanding

The discovery of high temperature superconductivity (HTSC) in oxide compounds has confronted materials scientists with many challenging problems. These include the preparation of ceramic samples with critical current density of about 106 A/cm2 at 77 K and sufficient mechanical strength for large-scale electrotechnical and magnetic applications and the preparation of epitaxial thin films of high structural perfection for electronic devices.The main interest in the growth of single crystals is for the study of physical phenomena, which will help achieve a theoretical understanding of HTSC. Theorists still do not agree on the fundamental mechanisms of HTSC, and there is a need for good data on relatively defect-free materials in order to test the many models. In addition, the study of the role of defects like twins, grain boundaries, and dislocations in single crystals is important for understanding such parameters as the critical current density. The study of HTSC with single crystals is also expected to be helpful for finding optimum materials for the various applications and hopefully achieving higher values of the superconducting transition temperature Tc than the current maximum of about 125 K. It seems unlikely at present that single crystals will be used in commercial devices, but this possibility cannot be ruled out as crystal size and quality improve.

A SDUTY OF SUPERCONDUCTING OXIDE Y-Ba-Cu-Sn-O

1987 ◽  
Vol 01 (02) ◽  
pp. 277-280 ◽  
Author(s):  
Xin Jin ◽  
Huimin Shao ◽  
Guiqin Wang ◽  
Mu Lu ◽  
Hanhe Zhang ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Hysteresis ◽  
X Ray Diffraction ◽  
X Ray

A high-Tc superconductor YBa2Cu3 Snx07+z was characterized. We observed the existence about 90K superconductivity in variety of compositions. The samples were examined by x-ray diffraction , Mössbauer, SEM and EDS. Their structure are still ABO3 perovskite but part of Cu atoms are displaced by Sn. It was observed that when the x increased the critical current density were increased based on the measurements of magnetic hysteresis.

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