Thermally activated dissipation in epitaxial Bi2Sr2CaCu2O8 + δ films evidence for the occurence of vortex strings with three-dimensional fluctuations in low magnetic fields

Miu, L.; Wagner, Patrick; Hadish, A.; Hillmer, F.; Adrian, H.

doi:10.1016/0921-4534(94)90570-3

Cited by 18 publications

(15 citation statements)

References 26 publications

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“…Note that U J depends on the magnetic field and the temperature, and the sharp decrease in n with H (figures 4(a) and (b)) indicates that U J = nkT decreases sharply with H, which subsequently causes a sharp decrease in J c . Kucera et al and Miu et al investigated the dependence of the resistance of Bi2212 thin films on H and T in the flux-liquid regime where the linear resistivity ρ lin = (E/J) J→0 is not zero, and found that the resistance was approximated by the thermally activated form: R(H, T) ≈ R 0 exp(−U 0 /kT), [23,24]. Similar dependence of U 0 on H and T has also been observed for the resistivity of Bi2223 thin films [21,25], and such dissipation has been attributed to the thermally activated plastic deformations of a viscous flux liquid with the formation of double kinks [23][24][25], because the observed (1 − T/T c )/H 1/2 dependence of U 0 is well explained by the theories of Geshkenbein et al and Vinokur et al [26].…”

Section: Resultsmentioning

confidence: 99%

Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Yamasaki

Endo

2014

Supercond. Sci. Technol.

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The dependence of the critical current density (J c ) and current-voltage (I-V) characteristics on the magnetic field H and temperature T were determined in c-axis-oriented epitaxial Bi 2 Sr 2 CaCu 2 O 8+x (Bi2212) thin films prepared by metalorganic chemical vapor deposition. The films showed high T c (R = 0) ≥ 83 K and high transport J c > 10 10 A m −2 at 10 K, but J c decreased sharply when a magnetic field was applied in the c direction, except at low temperatures (≤20 K). The n-values (indices of the power-law I-V characteristics) decreased together with J c , showing that the decrease is caused by thermally activated flux motion. To clarify the flux pinning mechanism operating in the films, nanostructural defects were investigated by transmission electron microscopy (TEM). Cross-sectional TEM images of the thin films revealed that the Bi2212 phase was twinned and that the twin boundary runs either parallel or perpendicular to the ab-plane depending on the region. We observed misfit dislocations at twin boundaries, and other dislocations associated with stacking faults parallel to the ab-plane, as well as anti-phase boundaries. Contrasts corresponding to dislocations parallel to the ab-plane and/or to the anti-phase boundaries were observed in plan-view TEM images, and nanoscale precipitates as observed in some YBa 2 Cu 3 O 7−y (YBCO) films were almost entirely absent. The temperature dependence of low-field J c , which was mostly unaffected by the thermally activated flux motion, approximately followedThe temperature dependence with m ≈ 2, which can be explained by a simple theoretical model, was recently observed in YBCO thin films in which flux pinning was dominated by linear pins (partial dislocations surrounding stacking faults parallel to the ab-plane). From these results and theoretical considerations on the flux pinning force, we conclude that flux pinning in our Bi2212 films is mainly caused by dislocations parallel to the ab-plane and anti-phase boundaries.

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Section: Resultsmentioning

confidence: 99%

Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Yamasaki

Endo

2014

Supercond. Sci. Technol.

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“…20 For example, we defined the ''irreversibility temperature'' T R as the temperature value where (T R )/(120 K)ϭ10 Ϫ4 . The resulting T R (B) line is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Vortex-liquid entanglement inBi2Sr2CaCu2
Miu
¹
,
Jakob
²
,
Haibach
³

et al. 1998
Phys. Rev. B
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2
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0
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We have investigated the thermally activated behavior of the in-plane electrical resistivity of Bi 2 Sr 2 CaCu 2 O 8ϩ␦ films for magnetic fields Bр10 4 G applied parallel to the c axis. The activation energy in the vortex-liquid state changes suddenly at a crossover field B cr . The anisotropy reduction generated by oxygen annealing leads to the increase of the crossover field. For BϽB cr , the activation energy U is weakly magnetic-field dependent. For BϾB cr , U(B,T)ϳ(1ϪT/T c0 )/B 1/2 , which corresponds to an entangled vortex fluid. The observation of vortex-liquid entanglement in the presence of relevant quenched disorder is discussed in connection with the relation between the theoretically predicted entanglement length for a clean system and the collective pinning length along the field direction. Our results suggests that, in the case of a pronounced anisotropy and significant collective pinning, the entanglement field B E ϭB cr Ϸ⌽ 0 /␥ 2 s 2 , where s is the interlayer spacing.

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“…Films prepared as such are also free of grain boundaries and so are most appropriate for investigations of the intrinsic properties of the Bi system. Several papers have already been published investigating the magnetic phase diagram, which contains several regimes of different behaviour [5,6], the electronic structure [7], which is crucial for the understanding of superconductivity, or the effect of pinning on the critical current, which is of great importance from the point of view of applications [8]. Investigation of the magnetic properties of the Bi system directly through magnetization measurements is in progress.…”

Section: Pole-figure Results and Discussionmentioning

confidence: 99%

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Holiastou

Psyharis

Niarchos

et al. 1997

Supercond. Sci. Technol.

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Thin films of the three members of the superconducting series Bi 2 Sr 2 Ca n−1 Cu n O 2n+4 , n = 1, 2, 3, were prepared by diode sputtering. X-ray characterization shows that all the films are single phase and c-axis oriented and in addition they are epitaxially grown. The latter is found by x-ray pole-figure measurements taken with a four-circle diffractometer. These are emphasized in this work. AC susceptibility measurements show that, while the 2201 films are not superconducting until 4 K, the transition temperatures of the 2212 films are 82 K-90 K and of the 2223 films 84 K-89 K.

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Thermally activated dissipation in epitaxial Bi2Sr2CaCu2O8 + δ films evidence for the occurence of vortex strings with three-dimensional fluctuations in low magnetic fields

Cited by 18 publications

References 26 publications

Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Vortex-liquid entanglement inBi2Sr2CaCu2
Miu
¹
,
Jakob
²
,
Haibach
³

et al. 1998
Phys. Rev. B
Self Cite
25
2
11
0
View full text Add to dashboard Cite

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

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Thermally activated dissipation in epitaxial Bi2Sr2CaCu2O8 + δ films evidence for the occurence of vortex strings with three-dimensional fluctuations in low magnetic fields

Cited by 18 publications

References 26 publications

Nanostructural defects for effective flux pinning in high-quality Bi2Sr2CaCu2O8+xepitaxial thin films with high critical current density

Nanostructural defects for effective flux pinning in high-quality Bi2Sr2CaCu2O8+xepitaxial thin films with high critical current density

Vortex-liquid entanglement inBi2Sr2CaCu2Miu1, Jakob2, Haibach3 et al. 1998Phys. Rev. BSelf Cite252110View full textAdd to dashboardCite

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

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Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Nanostructural defects for effective flux pinning in high-quality Bi₂Sr₂CaCu₂O_8+xepitaxial thin films with high critical current density

Vortex-liquid entanglement inBi2Sr2CaCu2
Miu
¹
,
Jakob
²
,
Haibach
³

et al. 1998
Phys. Rev. B
Self Cite
25
2
11
0
View full text Add to dashboard Cite