Two different thermally activated flux-flow regimes in oxygen-deficient<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</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">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:m

Qiu, Xin; Wuyts, B.; Maenhoudt, M.; Мощалков, В.В.; Bruynseraede, Y.

doi:10.1103/physrevb.52.559

Cited by 43 publications

(25 citation statements)

References 34 publications

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“…However, if we adopt the value ab (0)ϭ3.02 nm, H c2 (0) ϭ360 kOe, and ϭ89.3 given by our magnetization data and ␥ 2 ϭ1000 from our transport data, we end up with a value of L much too small compared to its real value as already pointed out in a previous report. 22 It should be recalled in this connection that similar formulas having the same T dependence have been derived by Daemen et al 48 and Ikeda 49 on different grounds, with different expressions for H 0 where the interlayer distance s appears explicitly in place of L. We have found that using Ikeda's formula "H 0 ϭ⌽ 0 3 /͓4 2 0 k B s␥ 2 ab 2 (0)͔…, and the values sϭ1.54 nm, ab (0)ϭ270 nm, our H 0 yields the result ␥ 2 ϭ857, which is well within the range observed in this experiment. We hasten to stress though that this should not be taken as an indication favoring a 3D-2D decoupling transition instead of a DE-E transition, since the region considered here lies below H 2D , and the appearance of nonvanishing c as we cross the H E line to the right does not necessary imply the complete decoupling of the pancake vortices into a 2D system.…”

Section: Resultsmentioning

confidence: 97%

“…38 These two liquid regimes were either assigned as the TAFF and FF regimes 20 or two distinct ͑low and high͒ TAFF regimes. 22,25 One may further explore a possible correlation between these two regimes with the disentangled and entangled vortex FIG. 1.…”

Section: Resultsmentioning

confidence: 98%

“…The entangled ͑E͒ and disentangled ͑DE͒ phases are supposed to exhibit different transport characteristics, and can hence be investigated from measurements of their transport properties. While the possible existence of the more elusive disentangled phase has been discussed in previous reports on YBCO-123, [21][22][23] BSCCO-2212, 12 and an artificial layered MoGe/Ge system, 24 a more concrete experimental picture have so far been reported in YBCO-124 only. 25 Obviously, additional studies are required before a more comprehensive picture of this particular vortex phase emerges.…”

Section: Introductionmentioning

confidence: 91%

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Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

et al. 2000

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We show that excessive Pb substitution of Bi in oxygen-overdoped BSCCO-2212 single crystal further reduces the anisotropy ( c / a ratio͒ of the system in addition to enhancing disorder in its vortex system. These effects have led to the suppression of first-order vortex melting as well as a peculiar second-peak effect exhibiting a sensitive temperature dependence over an unusually broad temperature range. Our experimental data further reveal, in a Bi-based system, the presence of a disentangled vortex liquid phase separating the solid vortex from the entangled vortex liquid phase in the H-T diagram constructed from the transport and magnetization data. INTRODUCTIONThe unusually rich variety of vortex phases in the H-T phase diagram is one of the most remarkable features distinguishing the new copper oxide superconductors from the conventional type-II superconductors. The appearance of a vortex liquid phase over a large area in the H-T diagram initiated intensive research on the structure and characteristics of the liquid phase as well as the true nature of the related thermodynamical transition across its boundary with the solid phase. It has now been established theoretically 1-5 and confirmed experimentally 6-12 that vortex melting in a clean sample is a first-order transition, while the presence of disorder is likely to change its character into a more gradual or second-order process.It is also well known that the traditional picture of the solid vortex phase has been greatly modified by the presence of disorder and anisotropy. It has been found necessary to include, in addition to the ordered vortex lattice state at low H and T, the less ordered or disordered glassy state at the higher H-T regime. This is further complicated by the occurrence of dimensional crossover at a certain boundary within the solid phase. 2,8,13-15 Studies on second-peak effects in BSCCO-2212 superconductors also suggest further complications of the solid vortex phase. 16,17 No less complicated is the vortex liquid phase where a multiphase structure emerges as a result of the intricate interplay among the thermal fluctuation effect, the pinning, and Lorentz forces as well as the plastic response of the vortex lines in highly anisotropic superconductors. The BSCCO-2212 superconductor, among others, offers a particularly rich and novel phenomenology of the vortex system due to its high T c and strongly layered structure. It has thus become one of the most intensely studied systems to date. It is theoretically predicted that apart from the metal-like viscous liq-

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 91%

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Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

et al. 2000

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“…10,11 A logarithmic magneticfield dependence was reported for YBa 2 Cu 3 O 7 /PrBa 2 Cu 3 O 7 superlattices 10 and YBa 2 Cu 3 O 7−x thin films respectively. 12 It is known that the shape of pinning potential and the pinning strength distribution influence the U (H) dependence. For an exponential type of pinning energy distribution, U (H) has a ln B dependence.…”

Section: Introductionmentioning

confidence: 99%

EFFECT OF Ni SUBSTITUTION FOR Cu IN THE VORTEX STATE OF (Bi,Pb):2223 SUPERCONDUCTOR

Pop

1999

Int. J. Mod. Phys. B

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The influence of the partial substitution of x = 0.02 Ni for Cu on the magnetoresistivity in the (Bi,Pb):2223 superconductor has been investigated. The resistive transitions were studied under magnetic fields up to 0.7 Tesla by using the dρ/dT versus T curves. The Arrhenius plots shows that the dissipation processes are induced by two distinct regimes. In the high temperature regime the activation energy is proportional to ln B and to B −1 in low temperature regime. The main dissipation processes in these regimes are discussed.

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“…Also, attention was given to the possibility of pinning in the vortex-liquid phase [5,10,11,26] and to different dissipation mechanisms above the melting line [5,13,[27][28][29]. Irreversibility due to geometrical [7,9] or surface barriers [22] have also been proposed, but these mechanisms are less probable in thin Y Ba 2 Cu 3 O 7−δ films with strong pinning.…”

Section: Introductionmentioning

confidence: 99%

Origin of the irreversibility line in thinYBa2Cu3O
Prozorov
¹
,
Kończykowski
²
,
Schmidt
³

et al. 1996
Phys. Rev. B
20
0
6
0
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We report on measurements of the angular dependence of the irreversibility temperature T irr (θ) in Y Ba 2 Cu 3 O 7−δ thin films, defined by the onset of a third harmonic signal and measured by a miniature Hall probe. From the functional form of T irr (θ) we conclude that the origin of the irreversibility line in unirradiated films is a dynamic crossover from an unpinned to a pinned vortex liquid. In irradiated films the irreversibility temperature is determined by the trapping angle.

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Two different thermally activated flux-flow regimes in oxygen-deficientYBa2Cu3

Cited by 43 publications

References 34 publications

Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

EFFECT OF Ni SUBSTITUTION FOR Cu IN THE VORTEX STATE OF (Bi,Pb):2223 SUPERCONDUCTOR

Origin of the irreversibility line in thinYBa2Cu3O
Prozorov
¹
,
Kończykowski
²
,
Schmidt
³

et al. 1996
Phys. Rev. B
20
0
6
0
View full text Add to dashboard Cite

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Two different thermally activated flux-flow regimes in oxygen-deficientYBa2Cu3

Cited by 43 publications

References 34 publications

Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

Effects of Pb substitution on the vortex state of oxygen-overdoped Bi2Sr2CaCu2O8+δ single crystal

EFFECT OF Ni SUBSTITUTION FOR Cu IN THE VORTEX STATE OF (Bi,Pb):2223 SUPERCONDUCTOR

Origin of the irreversibility line in thinYBa2Cu3OProzorov1, Kończykowski2, Schmidt3 et al. 1996Phys. Rev. B20060View full textAdd to dashboardCite

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Origin of the irreversibility line in thinYBa2Cu3O
Prozorov
¹
,
Kończykowski
²
,
Schmidt
³

et al. 1996
Phys. Rev. B
20
0
6
0
View full text Add to dashboard Cite