Effect of current sweep rate on critical current of superconducting Ag-Bi-2223 tapes

Ding, Shuo; Ren, Cheng; Yao, X.X.; Sun, Yu; Zhang, H.

doi:10.1016/s0011-2275(98)00072-1

Cited by 25 publications

(25 citation statements)

References 7 publications

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“…6 displays that the critical current density decreases with the increasing CSR (see Fig. 6), which is consistent with the experimental and numerical observations 14,23 .…”

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confidence: 88%

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Apparent negative mobility of vortex matter due to inhomogeneous pinning

Fangohr

Ding

et al. 2007

Phys. Rev. B

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We investigate the transport of vortices in superconductors with inhomogeneous pinning under a driving force. The inhomogeneity of pinning is simplified as strong-weak pinning regions. It is demonstrated that the interactions between the vortices captured by strong pinning potentials and the vortices in the week pinning region, cause absolute negative motion (ANM) of vortices: The vortices which are climbing towards the high barriers induced by the strong pinning with the help of driving force, move towards the opposite direction of the force and back to their equilibrium positions in the weak pinning region as the force is decreasing or withdrawn. Our simulations reveal that the hysteresis of ANM is determined by the competition between the speed of the negative motion which depends on the pinning inhomogeneity in superconductors and the speed of the driving force. Under the conditions of either larger force scanning rate or higher pinning inhomogeneity, a marked ANM and a larger hysteretic speed-force loop could be observed. This indicates that the time window to observe the ANM should be chosen properly. Moreover, the V-I characteristics of Ag sheathed Bi-2223 tapes are measured, and experimental observations are in qualitatively agreement with the simulation.

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“…6 displays that the critical current density decreases with the increasing CSR (see Fig. 6), which is consistent with the experimental and numerical observations 14,23 .…”

supporting

confidence: 88%

“…The distance between two voltage leads is L v =1cm and the distance between two current leads is 3cm, each of which is 1cm away from the voltage leads. The details of the sample preparation and measurement can be found in reference 23 .…”

mentioning

confidence: 99%

Apparent negative mobility of vortex matter due to inhomogeneous pinning

Fangohr

Ding

et al. 2007

Phys. Rev. B

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“…This power law E-j curves are observed frequently in transport measurements and can be used to determine the parameter n [15]. Certainly, n is dependent on flux pinning strength, magnetic field and temperature [18,27].…”

Section: B Boundary and Initial Conditionsmentioning

confidence: 93%

“…It is easy to see that U(j) = U 0 ln |j c /j| combined with E = E 0 exp(−U/kT ) leads to the power dependence of the E-j curve E = E 0 (j/j c ) n with n = U 0 /kT . This power law E-j curves are observed frequently in transport measurements and can be used to determine the parameter n [15]. Certainly, n is dependent on flux pinning strength, magnetic field and temperature [18,27].…”

Section: B Boundary and Initial Conditionsmentioning

confidence: 93%

“…First, at higher temperatures, such as liquid nitrogen temperatures, thermal fluctuation should be important and flux creep could influence the property of vortex matter apparently [13]. In fact the influence of flux creep on the V-I curve and transport property of Bi2223 have been confirmed by earlier experimental and numerical results [14,15,16,17,18]. Second, the quenched disorders or flux pinnings are inhomogeneous in polycrystalline high temperature superconductors (HTS).…”

Section: Introductionmentioning

confidence: 90%

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History effect in inhomogeneous superconductors

et al. 2002

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A model was proposed to account for a new kind of history effect in the transport measurement of a sample with inhomogeneous flux pinning coupled with flux creep. The inhomogeneity of flux pinning was described in terms of alternating weak pinning (lower j c ) and strong pinning region (higher j c ). The flux creep was characterized by logarithmic barrier. Based on this model, we numerically observed the same clockwise V-I loops as reported in references.Moreover, we predicted behaviors of the V-I loop at different sweeping rates of applied current dI/dt and magnetic fields B a , etc. Electric transport measurement was performed in Ag-sheathed Bi 2−x Pb x Sr 2 Ca 2 Cu 3 O y tapes immersed in liquid nitrogen with and without magnetic fields. V-I loop at certain dI/dt and B a was observed. It is found that the area of the loop is more sensitive to dI/dt than to B a , which is in agreement well with our numerical results.

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