Temperature, field and grain size dependence of flux pinning in high Tc superconductors

Smith, G.B.; Bell, John; Filipczuk, S.W.; Andrikidis, C.

doi:10.1016/0921-4534(89)90071-3

Cited by 25 publications

(5 citation statements)

References 10 publications

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“…2, the zero temperature activation energy barrier U, is field dependent. We did not find any simple functional form for this dependence and the best approximation is U,l/n which, for the moment, does not appear to be related by a simple way to traditional pinning models [16].…”

mentioning

confidence: 60%

“…For instance, if we write U(H, T) = Uo(H)(l -T/T,>n the resulting U is given by which reduces to = Uo(H) for n = 1. The n = 1 power law has received many recent experimental supports from resistivity measurements as well in YBa&usOi singl6crystal [161 as in films [13,16] and YBCO/P,BCO superlattices [13], where the shoulder on the resistivity below T, under magnetic field has been shown to originate from thermally activated flux motion [17]. As we have shown in a recent paper [HI, the shielding as reflected by x' and by XI' peak correspond to the resistivity reaching this shoulder level (p/pn -+ and in our case the relationship Dlf= cr12 reduces to Thus the slope of the Arrhenius plot of lnf gives us the zero temperature activation energy barrier and the prefactor Info = lnf, + Uo(H)/T,.…”

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confidence: 99%

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Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System

Khoder¹,

Couach²,

Henry³

et al. 1991

Europhys. Lett.

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The reversibility domain of the mixed state is known to be much less extended in the YBa2Cu307-6 system than in the other Bi-and T1-based high-T, cuprates. We show experimentally that increasing 6, the oxygen off-stoichiometry parameter, enhances the reversibility domain giving strong background to the correlation between the reversibility and the weakness of the interlayer coupling in these materials. A somewhat related dependence of the activation energy barrier U and the longitudinal correlation length L, with 6 is also shown.

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confidence: 60%

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confidence: 99%

Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System

Khoder¹,

Couach²,

Henry³

et al. 1991

Europhys. Lett.

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“…Coherence length (ξ ) and penetration depth (λ) values at the absolute zero temperature are obtained from the upper critical magnetic field and irreversibility field values, respectively. Moreover, activation energy values of the film are calculated using line pinning model and making linear fits to the low resistivity part of the transition [50][51][52][53].…”

Section: Methodsmentioning

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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“…More accurate values of U 0 can be obtained from transport rather than magnetic measurements due to the widening of the transition. The calculation of U 0 was made here by using the line pinning model [15] where U 0 was approximated from resistivity measurements [16,17] via an Arrheniustype method. With the assumption that the resistivity ρ has the following dependence…”

Section: Pinning Force and Activation Energymentioning

confidence: 99%

Effect of sintering periods on the pinning force, activation energy and microstructure of high- superconducting Bi - (Pb) - Sr - Ca - Cu - O tapes

Liu

Dou

1996

Supercond. Sci. Technol.

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Short and long periods of sintering of short single-core (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O 10+x tapes have been studied. Comparisons are made between three batches of these tapes with the same thermomechanical deformation and sintering conditions but with the starting precursor powders having undergone different processing. It is found that the volume density of the macroscopic pinning force in fields up to 1 T is greater for a particular sintering period. Resistivity measurements further show that the pinning activation energy also reaches a higher value for the same chosen sintering period. SEM images of the surfaces indicate that better core morphology and density can be achieved with this particular sintering period. Prolonged sintering leads to greater porosity while short-duration sintering inhibits grain growth and thus is of no assistance in the healing of cracks induced during the intermediate deformation between sintering periods.

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Temperature, field and grain size dependence of flux pinning in high Tc superconductors

Cited by 25 publications

References 10 publications

Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System

Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System

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

Effect of sintering periods on the pinning force, activation energy and microstructure of high- superconducting Bi - (Pb) - Sr - Ca - Cu - O tapes

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Temperature, field and grain size dependence of flux pinning in high Tc superconductors

Cited by 25 publications

References 10 publications

Interlayer Coupling and Reversibility in the High- T c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa 2 Cu 3 O 7-δ System

Interlayer Coupling and Reversibility in the High- T c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa 2 Cu 3 O 7-δ System

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

Effect of sintering periods on the pinning force, activation energy and microstructure of high- superconducting Bi - (Pb) - Sr - Ca - Cu - O tapes

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Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System

Interlayer Coupling and Reversibility in the High- T _c Superconductors: An Investigation in the Oxygen Off-Stoichiometric YBa ₂ Cu ₃ O _7-δ System