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 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

Effect of Cooling Rate on Critical Current Density for Bi2Sr2CaCu2O8+δ/Ag Composite Tapes

1992 ◽  
Vol 31 (Part 2, No. 8B) ◽  
pp. L1167-L1169 ◽  
Author(s):  
Jun-ichi Shimoyama ◽  
Jun-ichiro Kase ◽  
Takeshi Morimoto ◽  
Hitoshi Kitaguchi ◽  
Hiroaki Kumakura ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Cooling Rate ◽  
Critical Current ◽  
Current Density

STUDY OF THE TEXTURING IN BSCCO-AG TAPES THROUGH MAGNETIC MEASUREMENTS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3159-3164
Author(s):  
C. FERDEGHINI ◽  
M. R. CIMBERLE ◽  
G. GRASSO ◽  
P. GUASCONI ◽  
A. MALAGOLI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Longitudinal Direction ◽  
Magnetic Method ◽  
Superconducting Compounds

We have developed a method that allows, by a simple set of magnetic measurements, to study the texturing of the grains inside a BSCCO-Ag tape. Because the texture is anisotropic we define the angle ϑ L that identifies the mean grain misalignment angle with respect to the tape surface in longitudinal direction (i.e. rolling direction) and the angle ϑ T in transverse direction. The technique is based on the assumption that, because of the very high anisotropy of the critical current density in BSCCO superconducting compounds, the magnetic moment is essentially generated by the current circulating in the a-b planes of the BSCCO grains. The different magnetisation cycles, measured when the orientation of the magnetic field with respect to the tape surface is changed, depend only on the grain orientation inside the tape, which determines the effective magnetic field component normal to the a-b planes of the grains. Here we present the texture evolution of the BSCCO grains inside silver sheated multifilamentary tape starting from the initial steps of the mechanical deformation up to the final heating stage. The results obtained from the magnetic method are compared with those obtained with other methods, i.e. X-ray diffraction and critical current density anisotropy. Also results obtained on samples prepared in different way will be presented.

Effect of sintering temperature and cooling rate on microstructure, phase formation, and critical current density of Ag-sheathed Bi1.8Pb0.4Sr2Ca2Cu3Ox superconducting tapes

1998 ◽  
Vol 13 (2) ◽  
pp. 261-268 ◽  
Author(s):  
J. P. Singh ◽  
N. Vasanthamohan
Keyword(s):  
Critical Current Density ◽  
Cooling Rate ◽  
Critical Current ◽  
Current Density ◽  
Sintering Temperature ◽  
Superconducting Tapes ◽  
Temperature Quenching ◽  
Slow Cooling ◽  
Higher Temperature ◽  
Powder In Tube

Silver-sheathed Bi–Pb–Sr–Ca–Cu–O (2223) superconducting tapes (with a starting composition of Bi1.8Pb0.4Sr2Ca1Cu2O8, calcium cuprate, and CuO) were fabricated by the powder-in-tube technique. The tapes were sintered at various temperatures to optimize the formation of Bi1.8Pb0.4Sr2Ca2Cu3O10 phase within the tape. The results show that sintering within the temperature range of 815–825 °C can produce tapes with high critical current density (Jc). The Jc of samples sintered at the higher temperature of 825 °C, where more liquid is present, depended markedly on the rate at which tapes were cooled from the sintering temperature; samples sintered at lower temperatures did not exhibit such a cooling-rate effect. The optimum combination of phase purity and microstructure that yielded an average transport Jc of ≥ 2.5 × 104 A/cm2 was obtained when the tapes were sintered at 825 °C for 150 h and cooled at a rate of 25 °C/h from the sintering temperature. Quenching studies indicate that the Bi-2223 phase becomes unstable below 700 °C during slow cooling. This result may have important implications for processing Bi–Sr–Ca–Cu–O tapes with high Jc. Addition of 15 vol.% Ag flakes to the monolithic core exerted no significant effect on Jc.

scholarly journals Enhancement of the 77 K irreversibility field and critical current density of (Bi,Pb)2Sr2Ca 2Cu3Ox tapes by manipulation of the final cooling rate

1996 ◽  
Vol 69 (19) ◽  
pp. 2915-2917 ◽  
Author(s):  
J. A. Parrell ◽  
D. C. Larbalestier ◽  
G. N. Riley ◽  
Q. Li ◽  
R. D. Parrella ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Cooling Rate ◽  
Critical Current ◽  
Current Density ◽  
Irreversibility Field

Change of Superconducting Parameters of Y-Ba-Cu-O Slabs and Rings due to High-Energy Ion Beams

2006 ◽  
Vol 47 ◽  
pp. 63-68
Author(s):  
I. Kirschner ◽  
A. Balogh ◽  
Cs. Mészáros ◽  
R. Laiho ◽  
Gy. Kovács ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
High Energy ◽  
External Irradiation ◽  
High Tc ◽  
Fitting Method ◽  
Properties Of Materials ◽  
Superconducting Parameters

Different high-Tc superconducting Y-Ba-Cu-O samples of slabs and rings have been investigated. Using differently prepared Y1Ba2Cu3O7-d materials, significant deviations between irradiated and unirradiated specimens have been detected in their properties. These investigations demonstrate that unlikely prepared superconductors are differently sensitive to the external irradiation, although they have the same composition. The irradiation applied during these experiments consisted of high-energy Bi-ions with the flux of 5x1010 ions/cm2 and with the energy of 720 MeV. As is experienced, a considerable variation of the magnetic moment in the extent of 19-44% and a significant increase of the critical current density up to 41% can be detected. These originate from the change of the properties of materials due to the irradiation. For the evaluation of the experiments a new fitting method is elaborated for the temperature dependence of the critical current density, providing fully correct results for the whole temperature interval. The A.C. magnetic measurements show, that the irradiation causes to reach the state of the perfect diamagnetism at higher temperatures, than in the case of unirradiated samples. Similarly, the irradiated specimens have much lower losses, than the unirradiated ones and even these smaller values disappear at low temperatures.

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