Vortex-mobility determined NMR properties in highly anisotropic high-Tc superconductors II. Experiment on Tl2Ba2CaCu2O8

Moonen, J. T.; Brom, H.B.

doi:10.1016/0921-4534(95)00040-2

Cited by 12 publications

(9 citation statements)

References 29 publications

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“…27 For the fluorine doped Y-Ba-Cu-O system, the values of ␣ϭ0.60 at Tϭ68 K and ␣ϭ0.58 at Tϭ76 K, are in an excellent agreement with the theory presented in this paper. Then the relaxation regime changes to the diffusion one described by the exponential time dependence exp͓Ϫ(t/T 1dif )͔, where T 1di f is complicated function of ␦ and ⌬, which for the same limiting cases have been simplified.…”

Section: Discussionsupporting

confidence: 88%

“…In addition to our own experimental study of the spinlattice relaxation, we compare calculated results to Moonen and Brom's 205 Tl NMR measurements on the layered high-T c superconductor Tl 2 Ba 2 CaCu 2 O 8 . 27 They found the magnetization recovery is exponential with ␣ϭ1 at temperatures above T c , but as the temperature is decreased below T c , the ␣ values decrease with the temperature to ␣ϭ0.8, which is very close to the calculated value of ␣ϭ0.9. Now let us discuss the field dependence of relaxation times for the direct relaxation regime.…”

Section: Discussionsupporting

confidence: 79%

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Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

et al. 2000

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The theory of nuclear-spin diffusion is extended to the case of a nuclear-spin system in the type-II superconductors subjected to the external magnetic field of the intermediate range. We showed that at the beginning of the relaxation process the direct relaxation regime is implemented with nonexponential time dependence. Then the relaxation regime changes to the diffusion one. The analytical expressions are obtained for the dependencies of relaxation rate on the magnetic field value. Experiments performed on the fluorine doped Y-Ba-Cu-O system yield results in agreement with theory, both in respect of the NMR and the vortex models.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 79%

Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

et al. 2000

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“…[115] 151-155 [118] Tl 2 Ba 2 CaCu 2 O 8 12,000 650 150 [119] 12.9 [26] 103 ± 1. [120] 0.6 [121] ± 0.1 139, 188 [122] (Y,Dy)Ba 2 Cu 3 O 7 500,000 850 95 [40] 31.8 [123] 92. [124] 2.7 [125] 125 [126] (Y,Dy)Ba 2 Cu 3 O 7 500,000 1400 95 [40] 26 [25] 87.…”

Section: Material/refmentioning

confidence: 99%

Thermodynamic Parameters of Single‐ or Multi‐Band Superconductors Derived from Self‐Field Critical Currents

2017

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Key questions for any superconductor include: what is its maximum dissipation-free electrical current (its 'critical current') and can this be used to extract fundamental thermodynamic parameters? Present models focus on depinning of magnetic vortices and implicate materials engineering to maximise pinning performance. But recently we showed that the self-field critical current for thin films is a universal property, independent of microstructure, controlled only by the penetration depth. Here we generalise this observation to include thin films, wires or nanowires of singleor multi-band s-wave and d-wave superconductors. Using extended BCS equations we consider dissipation-free self-field transport currents as London-Meissner currents, avoiding the concept of pinning altogether. We find quite generally, for type I or type II superconductors, the current is limited by the relevant critical field divided by the penetration depth. Our fits to 64 available data sets, from zinc nanowires to compressed sulphur hydride with critical temperatures of 0.65 to 203 K, respectively, are excellent. Extracted London penetration depths, superconducting energy gaps and specific heat jumps agree well with reported bulk values. For multiband or multiphase samples we accurately recover individual band contributions and phase fractions.

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“…While the applications of NMR to conventional type II superconductors have been limited [1,2], in high-T c superconductors (HTSC's) NMR studies of FL dynamics appear more promising. The random thermal motion of the FL's has been detected through the anomalous narrowing of the inhomogeneously broadened NMR line [3][4][5] and from the recovery of the transverse nuclear magnetization in a spin-echo experiment [6,7]. Also the motion of vortices driven by an electric current or by a change in the applied dc magnetic field has been detected through linewidth [8] and spin-echo measurements [9,10].…”

mentioning

confidence: 99%

Thermal Depinning of Flux Lines inHgBa2CuO4+δfrom
Bj
¹
,
Borsa
²
,
Sok
³

et al. 1996
Phys. Rev. Lett.
26
2
15
0
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Hg NMR spin-lattice relaxation rates in an aligned powder sample of the anisotropic high-T c superconductor HgBa 2 CuO 41d (T c 96 K) show anisotropy in the temperature interval 10 -50 K, with an extra contribution present for the external magnetic field parallel to the c axis. The extra contribution shifts with magnetic field in a way related to the irreversibility temperature T irr , indicating that the thermal motion of flux lines (FL's) is the cause of the extra relaxation. A simple model is presented to analyze the relaxation data and to extract values for the correlation time t c and the effective activation energy U of the FL motion.

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Vortex-mobility determined NMR properties in highly anisotropic high-Tc superconductors II. Experiment on Tl2Ba2CaCu2O8

Cited by 12 publications

References 29 publications

Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

Thermodynamic Parameters of Single‐ or Multi‐Band Superconductors Derived from Self‐Field Critical Currents

Thermal Depinning of Flux Lines inHgBa2CuO4+δfrom
Bj
¹
,
Borsa
²
,
Sok
³

et al. 1996
Phys. Rev. Lett.
26
2
15
0
View full text Add to dashboard Cite

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Vortex-mobility determined NMR properties in highly anisotropic high-Tc superconductors II. Experiment on Tl2Ba2CaCu2O8

Cited by 12 publications

References 29 publications

Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

Nuclear spin-lattice relaxation and spin diffusion in the mixed state of type-II layered superconductors

Thermodynamic Parameters of Single‐ or Multi‐Band Superconductors Derived from Self‐Field Critical Currents

Thermal Depinning of Flux Lines inHgBa2CuO4+δfromBj1, Borsa2, Sok3 et al. 1996Phys. Rev. Lett.262150View full textAdd to dashboardCite

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Thermal Depinning of Flux Lines inHgBa2CuO4+δfrom
Bj
¹
,
Borsa
²
,
Sok
³

et al. 1996
Phys. Rev. Lett.
26
2
15
0
View full text Add to dashboard Cite