Dependence of the flux-creep activation energy on the magnetization current for a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>1.86</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>0.14</mml:mn></mml:mrow></m

McHenry, M. E.; Simizu, S.; Lessure, H. S.; Maley, M. P.; Coulter, J.Y.; Tanaka, Isao; Kojima, H.

doi:10.1103/physrevb.44.7614

Cited by 182 publications

(71 citation statements)

References 26 publications

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“…An exponential temperature (as well as magnetic field) dependence of the critical current density in superconductors with weak pinning is expected from flux creep [18]. A precise analysis of these dependencies must also reflect the scaling of fundamental pinning related parameters on temperature, as well as on magnetic field [19]. To take into account the dependence of these parameters on temperature we have rescaled the temperature axis by a function g(T)=1-(T/T c ) 2 (see Figure 5b).…”

Section: Discussionmentioning

confidence: 99%

Magnetic flux jumps in texturedBi2Sr2CaCu2

et al. 2003

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Magnetic flux jumps in textured Bi2Sr2CaCu2O 8+δ have been studied by means of magnetization measurements in the temperature range between 1.95 K and Tc, in an external magnetic field up to 9 T. Flux jumps were found in the temperature range 1.95 K -6 K, with the external magnetic field parallel to the c axis of the investigated sample. The effect of sample history on magnetic flux jumping was studied and it was found to be well accounted for by the available theoretical models. The magnetic field sweep rate strongly influences the flux jumping and this effect was interpreted in terms of the influence of both flux creep and the thermal environment of the sample. Strong flux creep was found in the temperature and magnetic field range where flux jumps occur suggesting a relationship between the two. The heat exchange conditions between the sample and the experimental environment also influence the flux jumping behavior. Both these effects stabilize the sample against flux instabilities, and this stabilizing effect increases with decreasing magnetic field sweep rate. Demagnetizing effects are also shown to have a significant influence on flux jumping.

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Section: Discussionmentioning

confidence: 99%

Magnetic flux jumps in texturedBi2Sr2CaCu2

et al. 2003

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“…The size and variation of C with applied field required for a smooth fit of the data over a large temperature range was perceived to be physically unreasonable. 23 To overcome this, the introduction of a temperature scaling term was suggested, to separate the explicit temperature dependence of U e f f from the current dependence. This modified Maley's method can be verified by considering U e f f (J,H,T) as a separable function 25 of applied field, temperature, and current density.…”

Section: Analysis Theorymentioning

confidence: 99%

“…The first, as followed in Ref. 23, takes known temperature-scaling forms determined theoretically and applies them directly to the data. U e f f (J,H,T) is divided by the scaling term, and values for C are chosen to provide the best continuity of U e f f (J,H,T 0 ) over the entire temperature range.…”

Section: Analysis Theorymentioning

confidence: 99%

Effects of fission-fragment damage on vortex dimensionality in silver-sheathedBi2Sr2Ca
Marinaro
¹
,
Horvat
²
,
Dou
³

et al. 2003
Phys. Rev. B
2
2
2
0
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We report on the vortex dimensionality of uranium-doped Ag/Bi2223 tapes, before and after irradiation to a thermal-neutron fluence. The effective activation energies, as a function of current density and applied field, were calculated from dynamic magnetization relaxation measurements. A dimensional crossover from a threedimensional ͑3D͒ elastic creep regime to a 2D plastic creep was observed in the nonirradiated tape at an applied magnetic field 0 H cr Ϸ0.37 T, with an associated change in the flux hop velocity and temperature dependence. After the introduction of the fission-fragment damage by irradiation, a shift in the crossover to 0 H cr Ϸ0.65 T was observed. These results indicate an enhancement of the c-axis vortex coherence by the introduced splayed columnar defects, explaining the greater pinning efficiency of the uranium-fission method in Bi2223 rather than the less anisotropic Y123. Conflicting results obtained for the irradiated tape in the absence of any temperature scaling of the activation energies demonstrate the importance of the inclusion of scaling in the magnetization relaxation analysis.

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“…50 This dependence of U over J is a good approximation for the creep activation barrier in the single-vortex creep regime (limit μ → 0) and provides a proper fit of the experimental U (J ) dependence observed in different superconductors. [51][52][53][54] The divergence of U (J ) when J → 0 can be understood in the context of the collective pinning considering that in the vortexglass state vortex motion is possible only in the presence of a current. 44 In the case of this logarithmic dependence of the activation energy on the critical current, a power-law time dependence of the magnetization is expected.…”

Section: Introductionmentioning

confidence: 99%

Temperature and time scaling of the peak-effect vortex configuration in FeTe0.7Se0.3

et al. 2012

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An extensive study of the magnetic properties of FeTe 0.7 Se 0.3 crystals in the superconducting state is presented. We show that weak collective pinning, originating from spatial variations of the charge carrier mean free path (δl pinning), rules in this superconductor. Our results are compatible with the nanoscale phase separation observed on this compound and indicate that in spite of the chemical inhomogeneity, spatial fluctuations of the critical temperature are not important for pinning. A power-law dependence of the magnetization vs time, generally interpreted as the signature of a single-vortex creep regime, is observed in magnetic fields up to 8 T. For magnetic fields applied along the c axis of the crystal, the magnetization curves exhibit a clear peak effect whose position shifts when varying the temperature, following the same dependence as observed in YBa 2 Cu 3 O 7−δ . The time and temperature dependence of the peak position has been investigated. We observe that the occurrence of the peak at a given magnetic field determines a specific vortex configuration that is independent on the temperature. This result indicates that the influence of the temperature on the vortex-vortex and vortex-defect interactions leading to the peak effect in FeTe 0.7 Se 0.3 is negligible in the explored range of temperatures.

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Dependence of the flux-creep activation energy on the magnetization current for aLa1.86Sr0.14

Cited by 182 publications

References 26 publications

Magnetic flux jumps in texturedBi2Sr2CaCu2

Magnetic flux jumps in texturedBi2Sr2CaCu2

Effects of fission-fragment damage on vortex dimensionality in silver-sheathedBi2Sr2Ca
Marinaro
¹
,
Horvat
²
,
Dou
³

et al. 2003
Phys. Rev. B
2
2
2
0
View full text Add to dashboard Cite

Temperature and time scaling of the peak-effect vortex configuration in FeTe0.7Se0.3

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Dependence of the flux-creep activation energy on the magnetization current for aLa1.86Sr0.14

Cited by 182 publications

References 26 publications

Magnetic flux jumps in texturedBi2Sr2CaCu2

Magnetic flux jumps in texturedBi2Sr2CaCu2

Effects of fission-fragment damage on vortex dimensionality in silver-sheathedBi2Sr2CaMarinaro1, Horvat2, Dou3 et al. 2003Phys. Rev. B2220View full textAdd to dashboardCite

Temperature and time scaling of the peak-effect vortex configuration in FeTe0.7Se0.3

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Effects of fission-fragment damage on vortex dimensionality in silver-sheathedBi2Sr2Ca
Marinaro
¹
,
Horvat
²
,
Dou
³

et al. 2003
Phys. Rev. B
2
2
2
0
View full text Add to dashboard Cite