Flux focusing effects in planar thin-film grain-boundary Josephson junctions

Rosenthal, P.; Beasley, M. R.; Char, K.; Colclough, M. S.; Zaharchuk, G.

doi:10.1063/1.105660

Cited by 230 publications

(85 citation statements)

References 4 publications

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“…From the magnetic pattern [ Fig. 3(b)] we get that the distance between two side lobes B ∼ 1 mT is in good agreement with the predicted value B ∼ 1.84 0 /w 2 for thin-film planar junctions [24] considering w ∼ 2 μm.…”

Section: Transport Measurements and Discussionsupporting

confidence: 71%

Josephson effect through YBa2Cu3O7−δ /Au-encapsulated nanogaps

Baghdadi

Abay

Golubev³

et al. 2017

Phys. Rev. B

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We successfully fabricated and studied planar superconductor-normal-superconductor (SNS) Josephson junctions made of YBa 2 Cu 3 O 7−δ (YBCO) high-T C superconductor (S) and Au normal metal (N). The crucial step in fabrication was done by using a Pt/Au bilayer encapsulation of the patterned YBCO nanogap. This procedure preserves the YBCO nanogap from the degradation due to the contact with resists, water, and chemicals involved in further processing for hybrid devices. The junctions exhibit Fraunhofer-like modulation patterns and Shapiro steps when they are irradiated by a rf field. Furthermore, we analyzed the I C (T ) characteristics of our hybrid junctions employing a SINI S (superconductor-insulator-normal conductor-insulator-superconductor) model.

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Section: Transport Measurements and Discussionsupporting

confidence: 71%

Josephson effect through YBa2Cu3O7−δ /Au-encapsulated nanogaps

Baghdadi

Abay

Golubev³

et al. 2017

Phys. Rev. B

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“…From the distance of the minima in this dependence we can conclude that the magnetic field penetrates the GBJ as expected. Furthermore, the magnetic field penetrating the grain boundary is enhanced by a factor of order W/d due to flux focusing effects [103]. Here, W is the width of the GBJ and d the thickness of the junction electrodes.…”

Section: Andreev Bound States In D-wave Superconductorsmentioning

confidence: 99%

Andreev bound states in high temperature superconductors

et al. 1998

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Abstract. Andreev bound states at the surface of superconductors are expected for any pair potential showing a sign change in different k-directions with their spectral weight depending on the relative orientation of the surface and the pair potential. We report on the observation of Andreev bound states in high temperature superconductors (HTS) employing tunneling spectroscopy on bicrystal grain boundary Josephson junctions (GBJs). The tunneling spectra were studied as a function of temperature and applied magnetic field. The tunneling spectra of GBJ formed by YBa2Cu3O 7−δ (YBCO), Bi2Sr2CaCu2O 8+δ (BSCCO), and La1.85Sr0.15CuO4 (LSCO) show a pronounced zero bias conductance peak that can be interpreted in terms of Andreev bound states at zero energy that are expected at the surface of HTS having a d-wave symmetry of the order parameter. In contrast, for the most likely s-wave HTS Nd1.85Ce0.15CuO4−y (NCCO) no zero bias conductance peak was observed. Applying a magnetic field results in a shift of spectral weight from zero to finite energy. This shift is found to depend nonlinearly on the applied magnetic field. Further consequences of the Andreev bound states are discussed and experimental evidence for anomalous Meissner currents is presented.

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“…Indeed, the pseudo period of 1-3 Oe corresponds to a much larger effective area S R eff 9 µm 2 than the weak link itself. We have calculated numerically the magnetic field profile for contacts in the thin film limit, following Rosenthal et al 26 , by solving the London equation, ∇ 2 J s − λ −2 J s = 0 in a quasi 2D contact. A color map of the penetration of the field in the contacts appears in Fig.…”

Section: Fraunhofer Pattern Of the Josephson Junctionmentioning

confidence: 99%

“…By ignoring details of the microscopic vortex structure and dynamics, a macroscopic approach to the diamagnetic screening currents, based on the solution of the London equation in a quasi 2D contact, can reasonably account for the measured pattern if flux focusing effects are assumed in the planar thin- film weak link 26 . Sections VII and Section VIII contain a detailed summary and the conclusions, respectively.…”

mentioning

confidence: 99%

Incipient Berezinskii-Kosterlitz-Thouless transition in two-dimensional coplanar Josephson junctions

et al. 2016

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Superconducting hybrid junctions are revealing a variety of novel effects. Some of them are due to the special layout of these devices, which often use a coplanar configuration with relatively large barrier channels and the possibility of hosting Pearl vortices. A Josephson junction with a quasi ideal two-dimensional barrier has been realized by growing graphene on SiC with Al electrodes. Chemical Vapor Deposition offers centimeter size monolayer areas where it is possible to realize a comparative analysis of different devices with nominally the same barrier. In samples with a graphene gap below 400 nm, we have found evidence of Josephson coherence in presence of an incipient BerezinskiiKosterlitz-Thouless transition. When the magnetic field is cycled, a remarkable hysteretic collapse and revival of the Josephson supercurrent occurs. Similar hysteresis are found in granular systems and are usually justified within the Bean Critical State model (CSM). We show that the CSM, with appropriate account for the low dimensional geometry, can partly explain the odd features measured in these junctions.

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Flux focusing effects in planar thin-film grain-boundary Josephson junctions

Cited by 230 publications

References 4 publications

Josephson effect through YBa2Cu3O7−δ /Au-encapsulated nanogaps

Josephson effect through YBa2Cu3O7−δ /Au-encapsulated nanogaps

Andreev bound states in high temperature superconductors

Incipient Berezinskii-Kosterlitz-Thouless transition in two-dimensional coplanar Josephson junctions

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