Pinning mechanisms in Ag-sheathed Bi(Pb)SrCaCuO tapes

Liu, H.K.; Guo, Yuan; Dou, Shi Xue; Cassidy, S.M.; Cohen, L. F.; Perkins, G. K.; Caplin, A.D.; Savvides, N.

doi:10.1016/0921-4534(93)90763-g

Cited by 43 publications

(10 citation statements)

References 11 publications

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“…For the intact tape, the low field J c behaviour can be understood as an intergranular dissipation in the weak-links, leading to the power-like law typical in percolation. At high fields, the behaviour follows an exponential law suggesting a J c degradation by flux motion inside the grains [2]. For the bent tape, the low field regime disappears because the intergranular current contribution has been suppressed.…”

Section: Intragranular and Intergranular Behavioursmentioning

confidence: 82%

“…The direct consequence is a sharp decrease of the critical current density with the magnetic field at relatively 'high' temperatures (T ~ 77 K) [2,3]. An additional characteristic of Bi-2223 materials is their high anisotropy, leading to a severe dependence of the critical current density with respect to the magnetic field direction [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Intragranular and intergranular behaviour of multifilamentary Bi-2223/Ag tapes

Fagnard

Vanderbemden

Crate

et al. 2002

Physica C: Superconductivity

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This communication aims at reporting the superconducting properties of Bi-2223/Ag tapes determined by using various measuring techniques. First, the original samples have been characterized by electrical resistance, AC susceptibility, and DC magnetization. The transport (intergranular) critical current vs. magnetic field was also determined at T = 77 K using pulsed currents up to 40 A. Next, the same combination of experiments was performed on bent tapes in order to bring out relevant information concerning the strength of the intergranular coupling. The results show that intergranular and intragranular currents differ by at least one order of magnitude. Finally, additional magnetic measurements were carried out in order to determine the anisotropy ratio J c ab /J c c , which was found to lie around 30.

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Section: Intragranular and Intergranular Behavioursmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Intragranular and intergranular behaviour of multifilamentary Bi-2223/Ag tapes

Fagnard

Vanderbemden

Crate

et al. 2002

Physica C: Superconductivity

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“…However, whenever the superconductor is subjected to the strong currents, there will always be thermally activated flux flow (TAFF) where vortices hop from one pinning site to an adjacent pinning site, and in some cases, the rate stemmed from transition of the vortices can be measured [59][60][61]. Moreover, TAFF is an essential dissipation mechanism causing to a long resistive tail for the temperatures below the superconducting transition temperature [62,63]. Hence, the magnetoresistivity measurements give the reliable results for the activation energy values.…”

Section: Activation Energymentioning

confidence: 99%

Effect of Magnetic Field Direction on Magnetoresistivity, Activation Energy, Irreversibility and Upper Critical Field of Bi-2212 Thin Film Fabricated by DC Sputtering Method

Bal

Varılcı

2012

J Supercond Nov Magn

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This study aims to investigate the effect of magnetic field direction on superconducting properties of Bi-2212 thin film fabricated on MgO (100) substrate using the direct current (DC) magnetron reactive sputtering technique at 100 watt with the aid of magnetoresistivity measurements. The zero resistivity transition temperatures (T c ), irreversibility fields (μ 0 H irr ) and upper critical fields (μ 0 H c2 ) are deduced from the magnetoresistivity versus temperature curves under DC magnetic fields (parallel and perpendicular to c-axis) up to 5 T. Moreover, thermally activated flux flow (TAFF) model is studied for activation energy (U 0 ) values of the sample. It is found that the T c value decreases from 76.4 K to 39.1 K for the applied magnetic field perpendicular to c-axis (μ 0 H ⊥c-axis); likewise, the T c reduces towards 28.8 K with the increase in the applied field parallel to c-axis (μ 0 H c-axis). Furthermore, the U 0 values are found to decrease considerably with increasing applied magnetic field. In fact, the U 0 of 134.5 K is obtained to be smallest at 5 T field parallel to the c-axis. Additionally, both the μ 0 H irr and μ 0 H c2 values determined are also observed to reduce with the increase of the applied magnetic field. At absolute zero temperature (T = 0 K), the extrapolation of the μ 0 H irr (T ) and μ 0 H c2 (T ) curves is used to obtain the μ 0 H irr (0) and μ 0 H c2 (0) values of the film, respectively. The inner is found to be about 22.216 T (19.046 T) for the applied field perpendicular (parallel) to c-axis whereas the latter is determined to be about 54.095 T (126.522 T) for the applied field parallel (perpendicular) to c-axis, respectively, as a result of anisotropic behavior of the film prepared. On the other hand, penetration depths (λ) and coherence lengths (ξ ) inferred from μ 0 H irr (0) and μ 0 H c2 (0) values are obtained to be about 38.519 Å (41.601 Å) and 16.147 Å (24.685 Å) in the case of applied field perpendicular (parallel) to c-axis, respectively. Based on all the results, the change of the superconducting properties as a function of the magnetic field direction presents the anisotropy of the sample produced. X-ray diffraction (XRD) and scanning electron microscopy (SEM) examinations are also conducted for microstructural and phase analyses of the film.

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“…The two types of pinning centers showed different temperature dependence for J c , which was explained by a simple theory [6]. In contrast to (RE)BCO, there have been only a few studies on the flux-pinning mechanism of Bi-oxide superconductors [7], [8]. Very recently, we measured the magnetic-field dependence of J c and the nvalues (indices of the power-law E-J characteristics) at various Manuscript temperatures in c-axis-oriented epitaxial Bi 2 Sr 2 CaCu 2 O 8+X (Bi2212) thin films prepared by metal-organic chemical vapor deposition (MOCVD) [9].…”

Section: Introductionmentioning

confidence: 97%

Nanostructural Defects and Critical Current Densities in High-Quality <inline-formula> <tex-math notation="TeX">$\hbox{Bi}_{2}\hbox{Sr}_{2}\hbox{CaCu}_{2}\hbox{O}_{8+{\rm X}} $</tex-math></inline-formula> Epitaxial Thin Films Prepared by MOCVD

Yamasaki

Endo

2015

IEEE Trans. Appl. Supercond.

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Nanostructural defects were investigated by transmission electron microscopy in c-axis-oriented epitaxial Bi 2 Sr 2 CaCu 2 O 8+X (Bi2212) thin films with high T c (R = 0) ≥ 83 K and high transport critical current density of J c > 10 10 A/m 2 at 10 K. We observed misfit dislocations at twin boundaries, dislocations associated with stacking faults parallel to the a-b plane, and antiphase boundaries. We compared the magnetic-field dependent J c values at various temperatures in two Bi2212 films. About 110-nm-thick film A showed lower J c than ∼280-nm-thick film B at low temperatures (≤ 20 K) or in low magnetic fields (≤ 0.1 T). However, the J c of film B decreased more rapidly in high magnetic fields, leading to a crossover of the two J c -B curves at temperatures of 30 K and above. This is probably because film B contained a higher density of antiphase boundaries, which caused stronger pinning and higher J c values at low temperatures but may have caused enhanced thermally activated motion of pancake vortices that eventually resulted in lower J c values in high magnetic fields at moderate temperatures.

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Pinning mechanisms in Ag-sheathed Bi(Pb)SrCaCuO tapes

Cited by 43 publications

References 11 publications

Intragranular and intergranular behaviour of multifilamentary Bi-2223/Ag tapes

Intragranular and intergranular behaviour of multifilamentary Bi-2223/Ag tapes

Effect of Magnetic Field Direction on Magnetoresistivity, Activation Energy, Irreversibility and Upper Critical Field of Bi-2212 Thin Film Fabricated by DC Sputtering Method

Nanostructural Defects and Critical Current Densities in High-Quality <inline-formula> <tex-math notation="TeX">$\hbox{Bi}_{2}\hbox{Sr}_{2}\hbox{CaCu}_{2}\hbox{O}_{8+{\rm X}} $</tex-math></inline-formula> Epitaxial Thin Films Prepared by MOCVD

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