Thermodynamic observation of first-order vortex-lattice melting transition in Bi2Sr2CaCu2O8

Zeldov, E.; Majer, D.; Kończykowski, M.; Geshkenbeǐn, V. B.; Vinokur, V. M.; Shtrikman, Hadas

doi:10.1038/375373a0

Cited by 780 publications

(637 citation statements)

References 29 publications

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“…In the weak-pinning limit, measurements of thermodynamic quantities such as magnetization and heat capacity have confirmed the existence of a first-order melting transition in both Bi 2 Sr 2 CaCu 2 O x [9] and untwinned YBa 2 Cu 3 O 7 single crystals [10], while the resistive hysteresis observed in untwinned YBa 2 Cu 3 O 7 single crystals below the first-order vortexsolid melting transition temperature T M [1][2][3] has been attributed to the current-driven non-equilibrium effects below the thermodynamic transition [3]. Another current-induced phenomenon in weak-pinning systems is the 'peak effect', which refers to a peak feature in the critical current density (J c ) as a function of the temperature or magnetic field [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 95%

Current-driven vortex dynamics in untwinned superconducting single crystals

Jiang

Yeh

Tombrello

et al. 1997

J. Phys.: Condens. Matter

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Abstract. Current-driven vortex dynamics of type-II superconductors in the weak-pinning limit is investigated by quantitatively studying the current-dependent vortex dissipation of an untwinned YBa 2 Cu 3 O 7 single crystal. For applied current densities (J ) substantially larger than the critical current density (J c ), non-linear resistive peaks appear below the thermodynamic firstorder vortex-lattice melting transition temperature (T M ), in contrast to the resistive hysteresis in the low-current limit (J < J c ). These resistive peaks are quantitatively analysed in terms of the current-driven coherent and plastic motion of vortex bundles in the vortex-solid phase, and the non-linear current-voltage characteristics are found to be consistent with the collective flux-creep model. The effects of high-density random point defects on the vortex dynamics are also investigated via proton irradiation of the same single crystal. Neither resistive hysteresis at low currents nor peak effects at high currents are found after the irradiation. Furthermore, the current-voltage characteristics within the instrumental resolution become completely ohmic over a wide range of currents and temperatures, despite theoretical predictions of much larger J c -values for the given experimental variables. This finding suggests that the vortex-glass phase, a theoretically proposed low-temperature vortex state which is stabilized by point disorder and has a vanishing resistivity, may become unstable under applied currents significantly smaller than the theoretically predicted J c . More investigation appears necessary in order to resolve this puzzling issue.

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Section: Introductionmentioning

confidence: 95%

Current-driven vortex dynamics in untwinned superconducting single crystals

Jiang

Yeh

Tombrello

et al. 1997

J. Phys.: Condens. Matter

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“…Several experiments have convincingly demonstrated that the transition there is first-order in a sufficiently clean system at sufficiently low fields [8,9].…”

Section: Introductionmentioning

confidence: 99%

First-order melting and dynamics of flux lines in a model forYBa2Cu3
Ryu
¹
,
Stroud
²

1996
Phys. Rev. B
43
2
58
1
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We have studied the statics and dynamics of flux lines in a model for YBa 2 Cu 3 O 7−δ , using both Monte Carlo simulations and Langevin dynamics. The lines are assumed to be flexible but unbroken in both the solid and liquid states. For a clean system, both approaches yield the same melting curve, which is found to be weakly first order with a heat of fusion of about 0.02k B T m per vortex pancake at a field of 50kG. The time averaged magnetic field distribution experienced by a fixed spin is found to undergo a qualitative change at freezing, in agreement with NMR and µSR experiments. The calculations yields, not only the field distribution in both phases, but also an estimate of the measurement time needed to distinguish these distributions:we estimate this time as ≥ 0.5µsec. The magnetization relaxation time in a clean sample slows dramatically as the temperature approaches the mean-field upper critical field line H c2 (T ) from below. Melting in the clean system is accompanied by a proliferation of free disclinations and a simultaneous dis-1 appearance of hexatic order. Just below melting, the defects show a clear magnetic-field-dependent 3D-2D crossover from long disclination lines parallel to the c-axis at low fields, to 2D "pancake" disclinations at higher fields.Strong point pins produce an energy varying logarithmically with time. This ln t dependence results from slow annealing out of disclinations in disordered samples. Even without pins, the model gives subdiffusive motion of individual pancakes in the dense liquid phase, with mean-square displacement proportional to t 1/2 rather than to t as in ordinary diffusion. The calculated melting curve, and many dynamical features, agree well with experiment.

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“…The Peak Effect has been evidenced in various classes of type II superconductors, e.g. low-T c [8][9][10][11][12], high-T c [13][14][15], boro-carbides [16] and MgB 2 [17]; however, it has not been observed in Nb 3 Sn up to the present day, to the best of our knowledge. Nb 3 Sn crystallizes in the A15 type structure and is actually the most used material in the manufacturing of superconducting magnets at very high fields [18].…”

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confidence: 99%

Transition between the Bragg glass and the disordered phase inNb3Sndetected by third harmonics of the ac magnetic susceptibility

et al. 2006

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We report additional experimental evidences about the presence of an universal behavior in the Field-Temperature Phase Diagram of Type II Superconductors. This behavior is characterized by a phase transition in the vortex matter between the disordered and the Bragg Glass phase. The experimental detection of a Peak Effect phenomenon has been proved to be strictly connected to the existence of this phase transition. In this paper, we show the first observation of a Peak Effect in the compound Nb 3 Sn, by using 1 st harmonics of the AC magnetic susceptibility. Peak Effect has been detected at fields between 3T and 13T, whereas it is not observable at higher fields. This seems to be in contrast with the theoretical predictions of such a phase transition at all fields and, therefore, with the predicted universality in the magnetic behavior of the Type II superconductors. Nevertheless, by measuring the 3 rd harmonics of the AC susceptibility, this phase transition has been detected up to our highest available field (19 T), thus demonstrating the necessity of the higher harmonics analysis in studying these topics and moreover proving the validity of the theoretical predictions. Magnetic flux penetrates a type II superconductor in form of vortices, which distribute in a regular lattice in absence of defects [1,2]. Defects affect the lattice ordering, but prevent the dissipations associated to the vortex movement [2]. An universal field-temperature phase diagram has been supposed for all the type II superconductors with point defects. In this phase diagram a transition in the vortex lattice has been predicted, between a disordered phase and the Bragg Glass Phase [3,4]. This latter is characterized by a quasi long range order and a perfect topological order, in which the vortex lattice stills survives despite the presence of the pinning [3], as it has also been experimentally evidenced [5]. The disordered phase has been supposed to be again a glass phase ("multidomain glass"), but with a topological disorder at the largest length scales [4]. The critical current density, J c [6], generally decreasing with increasing temperature and/or magnetic field [2], shows a local maximum, known as Peak Effect [7], when the Disordered/Bragg Phase transition occurs. For this reason, the observation of the Peak Effect has been widely used to detect this phase transition [3]. The Peak Effect has been evidenced in various classes of type II superconductors, e.g. low-T c [8][9][10][11][12], high-T c [13][14][15], boro-carbides [16] and MgB 2 [17]; however, it has not been observed in Nb 3 Sn up to the present day, to the best of our knowledge. Nb 3 Sn crystallizes in the A15 type structure and is actually the most used material in the manufacturing of superconducting magnets at very high fields [18]. In the present work, measurements have been performed on a high quality Nb 3 Sn single crystal, furnished by M. Toyota [19] (Dimensions ≈ 3 x 1.32 x 0.43 mm 3 ). The sample was characterized by T c = 18.2 K, ΔT c = 0.1 K, T m = 38.84 K. A valu...

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Thermodynamic observation of first-order vortex-lattice melting transition in Bi2Sr2CaCu2O8

Cited by 780 publications

References 29 publications

Current-driven vortex dynamics in untwinned superconducting single crystals

Current-driven vortex dynamics in untwinned superconducting single crystals

First-order melting and dynamics of flux lines in a model forYBa2Cu3
Ryu
¹
,
Stroud
²

1996
Phys. Rev. B
43
2
58
1
View full text Add to dashboard Cite

Transition between the Bragg glass and the disordered phase inNb3Sndetected by third harmonics of the ac magnetic susceptibility

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Thermodynamic observation of first-order vortex-lattice melting transition in Bi2Sr2CaCu2O8

Cited by 780 publications

References 29 publications

Current-driven vortex dynamics in untwinned superconducting single crystals

Current-driven vortex dynamics in untwinned superconducting single crystals

First-order melting and dynamics of flux lines in a model forYBa2Cu3Ryu1, Stroud2 1996Phys. Rev. B432581View full textAdd to dashboardCite

Transition between the Bragg glass and the disordered phase inNb3Sndetected by third harmonics of the ac magnetic susceptibility

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First-order melting and dynamics of flux lines in a model forYBa2Cu3
Ryu
¹
,
Stroud
²

1996
Phys. Rev. B
43
2
58
1
View full text Add to dashboard Cite