Reentrant superconducting transport behavior of single grain boundary Josephson junction in BaPb1?xBixO3 Bicrystals

Roshchin, Igor V.; Stepankin, V.; Kuznetsov, A. V.

doi:10.1007/bf00751508

Cited by 4 publications

(6 citation statements)

References 8 publications

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“…At the same time, the inhomogeneity of electron characteristics is also inherent to the related solid solutions BPB, which was demonstrated by spatially resolved electron energy loss spectroscopy [465]. It is reasonable to suggest that this inhomogeneity both in BPB and high-T c oxides is strengthened near free surfaces in agreement with Josephson current measurements across BPB bicrystal tunnel boundaries [466].…”

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confidence: 57%

Competition of Superconductivity and Charge Density Waves in Cuprates: Recent Evidence and Interpretation

Gabovich

Войтенко

Ekino

et al. 2010

Advances in Condensed Matter Physics

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Explicit and implicit experimental evidence for charge density wave (CDW) presence in high-Tcsuperconducting oxides is analyzed. The theory of CDW superconductors is presented. It is shown that the observed pseudogaps and dip-hump structures in tunnel and photoemission spectra are manifestations of the same CDW gapping of the quasiparticle density of states. Huge pseudogaps are transformed into modest dip-hump structures at low temperatures,T, when the electron spectrum superconducting gapping dominates. Heat capacity jumps at the superconducting critical temperature and the paramagnetic limit are calculated for CDW superconductors. For a certain range of parameters, the CDW state in ad-wave superconductor becomes reentrant withT, the main control quantity being a portion of dielectrcally gapped Fermi surface. It is shown that in the weak-coupling approximation, the ratio between the superconducting gap at zero temperatureΔ(T=0)andTchas the Bardeen-Cooper-Schrieffer value fors-wave Cooper pairing and exceeds the corresponding value ford-wave pairing of CDW superconductors. Thus, large experimentally found values2Δ(T=0)/Tc≈5÷8are easily reproduced with reasonable input parameter values of the model. The conclusion is made that CDWs play a significant role in cuprate superconductivity.

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confidence: 57%

Competition of Superconductivity and Charge Density Waves in Cuprates: Recent Evidence and Interpretation

Gabovich

Войтенко

Ekino

et al. 2010

Advances in Condensed Matter Physics

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“…Owing to its importance and appeal, this field is growing with remarkable speed, and the technologies developed for the fabrication of grain boundaries in high-T c superconductors are now being applied to other material systems such as the ferrates (Scholl et al, 2000), the bismuthates (Kussmaul, Hellman, et al, 1993;Inoue et al, 1994;Takami et al, 1994;Roshchin et al, 1995;Yamamoto et al, 1995), or the manganates showing colossal magnetoresistance (Mathur et al, 1997;Steenbeck et al, 1997;Todd et al, 1999;Westerburg et al, 1999;Hö fener et al, 2000).…”

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confidence: 99%

Grain boundaries in high-Tcsuperconductors

2002

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Since the first days of high-T c superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic superconductors, have made grain boundaries formed by high-T c cuprates important tools for basic science. They are moreover a key issue for electronic and large-scale applications of high-T c superconductivity. The aim of this review is to give a summary of this broad and dynamic field. Starting with an introduction to grain boundaries and a discussion of the techniques established to prepare them individually and in a well-defined manner, the authors present their structure and transport properties. These provide the basis for a survey of the theoretical models developed to describe grain-boundary behavior. Following these discussions, the enormous impact of grain boundaries on fundamental studies is reviewed, as well as high-power and electronic device applications. CONTENTS I. Introduction 485 II. Introduction to Grain Boundaries 486 III. Preparation of Single Grain Boundaries 488 A. Bicrystalline junctions 489 B. Biepitaxial junctions 489 C. Step-edge junctions 491 IV. Structural Properties 491 V. Transport Properties of Grain Boundaries 496 A. Current-voltage characteristics 496 B. Critical current density 498 1. Dependence on grain-boundary angle 498 2. Temperature dependence of the critical currents 502 3. Magnetic-field dependence of the critical currents 502 C. Current-phase relation 504 D. Normal-state resistivity 504 E. The I c R n product 505 F. Grain-boundary capacitance 506 G. Microwave properties 507 H. Grain-boundary noise 507 I. Self-generated magnetic flux 509 J. Penetration of magnetic flux into grain boundaries 510 VI. Effects of Doping 510 VII. Grain-Boundary Mechanisms 511 A. Mechanisms based on structural properties 511 B. Mechanisms based on deviations from ideal stoichiometry 512 C. Order-parameter symmetry-based mechanisms 514 D. Interface charging and band bending 515 E. Mechanisms based on direct suppression of the pairing mechanism 516 VIII. Control of Grain Boundaries with Electric Fields or Quasiparticle Injection 517 A. Applied electric fields 517 B. Quasiparticle injection 518 IX. Irradiation of Grain Boundaries 518 A. Irradiation with electrons 518 B. Irradiation with light 518 C. Irradiation with ions 519 X. Bulk Applications 519 A. Powder-in-tube method 520 B. Coated conductors 520 XI. Applications of Grain Boundaries in Thin Films 522 A. SQUIDs 522 B. Radiation detectors and spectrometers 524 C. Three-terminal devices 525 D. Superconducting logic circuits 526 E. Research devices 526 XII. Summary and Outlook 528 Acknowledgments 529 References 529

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“…Previous reports of BPBO polycrystalline films found significant suppression of T c already apparent at 200 nm, a much larger thickness than the onset of T c reduction in our epitaxial films [17]. Grain boundaries in polycrystalline BPBO form Josephson junctions [18,19].…”

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confidence: 46%

Superconductivity-localization interplay and fluctuation magnetoresistance in epitaxial BaPb1−xBixO3 thin films

Harris

Campbell

Uecker

et al. 2018

Phys. Rev. Materials

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BaPb 1−x Bi x O 3 is a superconductor, with transition temperature T c = 11 K, whose parent compound BaBiO 3 possess a charge ordering phase and perovskite crystal structure reminiscent of the cuprates. The lack of magnetism simplifies the BaPb 1−x Bi x O 3 phase diagram, making this system an ideal platform for contrasting high-T c systems with isotropic superconductors. Here we use high-quality epitaxial thin films and magnetotransport to demonstrate superconducting fluctuations that extend well beyond T c . For the thickest films (thickness above ∼ 100 nm) this region extends to ∼ 27 K, well above the bulk T c and remarkably close to the higher T c of Ba 1−x K x BiO 3 (T c = 31 K). We drive the system through a superconductor-insulator transition by decreasing thickness and find the observed T c correlates strongly with disorder. This material manifests strong fluctuations across a wide range of thicknesses, temperatures, and disorder presenting new opportunities for understanding the precursor of superconductivity near the 2D-3D dimensionality crossover.1 arXiv:1801.03864v2 [cond-mat.supr-con] In contrast to the layered cuprate superconductors, BaPb 1−x Bi x O 3 (BPBO, T c = 11 K) and Ba 1−x K x BiO 3 (BKBO, T c = 31 K) are isotropic and nonmagnetic, however, there are still interesting similarities [1,2]. The bismuthates are complex oxides with oxygen octahedra similar to the cuprates, and the parent insulating BaBiO 3 (BBO) possesses a competing phase, a charge density wave (CDW), which is suppressed for superconducting compositions.The study of the simpler, conventional bismuthate may lead to a deeper understanding of the role of CDW physics in the more complicated cuprates. The cuprate phase diagram is characterized by numerous electronic and magnetic phases and the properties are strongly influenced by disorder [3]. In thin conventional superconductors, disorder can lead to a pseudogap reminiscent of the high-T c cuprates, suggesting a possible connection between the layered cuprate structure and dimensionally confined conventional superconductors [4].In superconducting BPBO single crystals, Luna et al.[5] found a reduction in the density of states consistent with a disorder-driven metal-insulator transition and predicted a disorderfree T c of 17 K in the strong coupling limit and 52 K in the weak coupling limit for x = 0.25.Here we demonstrate an extended region of positive magnetoresistance in epitaxial thin films of BaPb 0.75 Bi 0.25 O 3 that is well described by superconducting fluctuations. This fluctuation regime persists for the thickest films that are well within the 3D regime, consistent with the high disorder found in our films. Restricting film thickness causes a superconductor-toinsulator transition (SIT) that correlates with disorder. Although our results are consistent with the disorder levels found in bulk single crystals [5], we find that the critical thickness for superconductivity depends on extrinsic factors related to the poor lattice matching of BPBO with common perovskite substrate...

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Reentrant superconducting transport behavior of single grain boundary Josephson junction in BaPb1?xBixO3 Bicrystals

Cited by 4 publications

References 8 publications

Competition of Superconductivity and Charge Density Waves in Cuprates: Recent Evidence and Interpretation

Competition of Superconductivity and Charge Density Waves in Cuprates: Recent Evidence and Interpretation

Grain boundaries in high-Tcsuperconductors

Superconductivity-localization interplay and fluctuation magnetoresistance in epitaxial BaPb1−xBixO3 thin films

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