Magnetic field dependence of vortex activation energy: A comparison between MgB2, NbSe2 and Bi2Sr2Ca2Cu3O10 superconductors

Kaushik, S. D.; Braccini, V.; Patnaik, S.

doi:10.1007/s12043-008-0187-9

Cited by 28 publications

(23 citation statements)

References 29 publications

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“…3 because of the crossover to the regime of single vortex pinning where is constant. Similar dependencies have recently been found for polycrystalline MgB 2 , NbSe 2 36, and FeSe3738, as well as LiFeAs single crystals39.…”

Section: Resultssupporting

confidence: 82%

High field superconducting properties of Ba(Fe1−xCox)2As2 thin films

Hänisch

Iida

Kurth

et al. 2015

Sci Rep

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In general, the critical current density, Jc, of type II superconductors and its anisotropy with respect to magnetic field orientation is determined by intrinsic and extrinsic properties. The Fe-based superconductors of the ‘122’ family with their moderate electronic anisotropies and high yet accessible critical fields (Hc2 and Hirr) are a good model system to study this interplay. In this paper, we explore the vortex matter of optimally Co-doped BaFe2As2 thin films with extended planar and c-axis correlated defects. The temperature and angular dependence of the upper critical field is well explained by a two-band model in the clean limit. The dirty band scenario, however, cannot be ruled out completely. Above the irreversibility field, the flux motion is thermally activated, where the activation energy U0 is going to zero at the extrapolated zero-kelvin Hirr value. The anisotropy of the critical current density Jc is both influenced by the Hc2 anisotropy (and therefore by multi-band effects) as well as the extended planar and columnar defects present in the sample.

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Section: Resultssupporting

confidence: 82%

High field superconducting properties of Ba(Fe1−xCox)2As2 thin films

Hänisch

Iida

Kurth

et al. 2015

Sci Rep

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“…7a and b by solid curves for Si-doped and Sb-doped samples, respectively. These plots show a parabolic behavior which is similar to the behavior observed for other high-T c and Nb 3 Sn -type superconducting compounds [41]. The derived values of parameters (with d value set to 2) are mentioned in Fig.…”

Section: Resultssupporting

confidence: 79%

“…Our results show that the TAFF activation energy, U 0 (H) follows a parabolic dependence on magnetic field which is interpreted as a consequence of grain boundary pinning. The activation energy in these materials is found to obey the scaling law as postulated by Kramer [40,28,41], namely: U 0-(H) = AH c (1 À H/H Ã ) d , where H Ã is the scaling field which is mostly considered to be the irreversibility field, H irr or a Kramer scaling field, H Ã , d and c are fitting parameters [41]. In this expression, the component (1 À H/H Ã ) d represents the suppression of superconductivity due to the application of magnetic field and the component H c represents the variation due to decreasing critical current density with increasing magnetic field.…”

Section: Resultsmentioning

confidence: 71%

Effect of Sb and Si doping on the superconducting properties of FeSe0.9

Sudesh

Rani

Varma

2013

Physica C: Superconductivity

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a b s t r a c tIn the present work, we have studied the effect of doping Sb and Si at the Se-site of FeSe 0.9 on the superconducting properties, such as transition temperature (T c ), upper critical field (H c2 ) and irreversibility field (H irr ). The polycrystalline samples have been synthesized via two step solid state reaction route with nominal compositions Fe[Se 1Àx (Sb/Si) x ] 0.9 (x = 0.0, 0.05, 0.10, 0.15 and 0.20). The X-ray diffraction resultsshow the presence of tetragonal a-FeSe phase with the P4/nmm space group symmetry in all the samples.The highest superconducting onset temperatures, T onset c $ 9:42 K and 9:20 K, respectively, for Si and Sb doped samples have been found for x = 0.05. The temperature dependence of H c2 (T) and H irr (T) have been calculated from the magnetoresistance data using the criteria of 90% and 10% of normal state resistivity (q n ) values, respectively. The values of H c2 (0) estimated from Werthamer-Helfand-Hohenberg (WHH) and Ginzburg-Landau (GL) theories are found to follow the same trends and maximum H c2 (0) is found for the composition x = 0.10 for both the Si and Sb doped samples. The irreversibility field, H irr and activation energy, U 0 have also been calculated to study the vortex motion behavior of the samples. A clear cut correlation between H irr and U 0 has been found.

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“…The resistivity in this regime is given by ρ=ρ o (B,T) e -U 0 /κ B T where, ρ o is the pre exponential factor, κ B is the Boltzmann's constant and U 0 is the characteristic TAFF activation energy, which is slightly temperature and magnetic field dependent. The activation energy show parabolic behavior or exhibits different power law exponent with magnetic field, depending on the type of superconductor or precisely the flux pinning in them [6]. There have been many reports regarding temperature and field dependence of activation energy in various HTSC.…”

Section: Introductionmentioning

confidence: 99%

Temperature and field dependence of thermally activated flux flow resistance in Bi2Sr2CaCu2O8+δ superconductor

Sharma

Kumar²,

Awana

2012

Solid State Communications

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We study the temperature dependence of the resistivity as a function of magnetic field in superconducting transition (T c onset -T c R=0 ) region for different Bi 2 Sr 2 CaCu 2 O 8+δ superconducting samples being synthesized using sol-gel method. The superconducting transition temperature (T c R=0 ) of the studied samples is increased from 32 K to 82K by simply increasing the final sintering temperature with an improved grains morphology. On the other hand, broadening of transition is increased substantially with decrease in sintering temperature; this is because T c onset is not affected much with grains morphology. Further broadening of the superconducting transition is seen under magnetic field, which is being explained on the basis of thermally activated flux flow (TAFF) below superconducting transition temperature (T c ). TAFF activation energy (U 0 ) is calculated using the resistive broadening of samples in the presence of magnetic field. Temperature dependence of TAFF activation energy revealed linear temperature dependence for all the samples. Further, magnetic field dependence is found to obey power law for all the samples and the negative exponent is increased with increase in sintering temperature or the improved grains morphology for different Bi-2212 samples. We believe that the sintering temperature and the ensuing role of grain morphology is yet a key issue to be addressed in case of cuprate superconductors.

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Magnetic field dependence of vortex activation energy: A comparison between MgB2, NbSe2 and Bi2Sr2Ca2Cu3O10 superconductors

Abstract: The dissipative mechanism at low current density is compared in three different classes of

Cited by 28 publications

References 29 publications

High field superconducting properties of Ba(Fe1−xCox)2As2 thin films

High field superconducting properties of Ba(Fe1−xCox)2As2 thin films

Effect of Sb and Si doping on the superconducting properties of FeSe0.9

Temperature and field dependence of thermally activated flux flow resistance in Bi2Sr2CaCu2O8+δ superconductor

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