A class of high-TcY Ba2Cu3O7−xgrain boundary junctions with high-IcRnproducts

Sarnelli, E.; Testa, Gianluca; Crimaldi, D; Monaco, A.; Navacerrada, M.A.

doi:10.1088/0953-2048/18/6/l03

Cited by 25 publications

(34 citation statements)

References 31 publications

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“…This phenomenological result, together with a linear relationship between the critical current density and the specific resistance values, make it reasonable to describe these junctions in a tunnel regime rather than in the filamentary framework. 9 Nevertheless, more structural and chemical studies for this substrate geometry are necessary to corroborate such results.…”

Section: B / T Ratio: Comparison Between 24°[001] Symmetric and 45°[mentioning

confidence: 95%

“…Then, only in a limited number of cases the I -V curves are well described by the resistively shunted junction model (RSJ model). 9 Nevertheless, because of the presence of hysteresis in most of them, we consider that a calculus of the C / A ratio in terms of the ␤ C parameter could be also appropriated. Tarte et al 23,27 found that the capacitance calculated from the Fiske resonance correlates well with that determined from the hysteresis measurements, but the analysis has mainly been performed on YBCO 24°and 36°[001] symmetrical JJs.…”

Section: B / T Ratio: Comparison Between 24°[001] Symmetric and 45°[mentioning

confidence: 99%

“…[4][5][6][7] At this stage, few studies on the structural and transport properties of JJs generated on substrates tilted around a-b planes have been presented. 8,9 The properties of these geometries have been more extensively studied in JJs fabricated by a biepitaxial technique which has shown to be a good option for the implementation of a reliable technology based on the Joshepson effect. [10][11][12] The structure of the barrier depends on many factors like the misorientation angle between the two electrodes, the orientation of the interface plane with respect to crystallographic axes, and the meandering at the barrier, so no prediction of the exact boundary structure is possible.…”

Section: Introductionmentioning

confidence: 99%

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Capacitance of Josephson junctions made on bicrystalline substrates of different geometries

et al. 2005

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Section: B / T Ratio: Comparison Between 24°[001] Symmetric and 45°[mentioning

confidence: 95%

Section: B / T Ratio: Comparison Between 24°[001] Symmetric and 45°[mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Capacitance of Josephson junctions made on bicrystalline substrates of different geometries

et al. 2005

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“…For high-T C SQUIDs the simple rule I C R N = const valid for low-T C SQUIDs does not apply in the case of interferometers based on the symmetric bicrystal c-axis [001] devices. In such ASQUIDs, I C R N is proportional to the critical current density J C at low values and stays roughly constant at high-J C values and changing one single parameter is now possible [6].…”

Section: Discussionmentioning

confidence: 99%

Self-Induced Resonances in Asymmetric Superconducting Quantum Interference Devices

Polak

Sarnelli

2008

Acta Phys. Pol. A

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Theory of self-induced resonances in asymmetric two-junction interferometer device is presented. An extension of previous theoretical approaches contains inclusions from several asymmetries: the Josephson current , capacitances χ and dissipation ρ presented in an equivalent circuit. Our theory can be useful to determine asymmetry parameters always present in lightly damped asymmetric SQUIDs made from low-and high-T C materials.

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“…1b) have been fabri cated [16][17][18][19][20][21][22][23][24][25] with an order of magnitude lower GB meandering and up to a threefold increase of the I c R n values [16][17][18][19]. A complete antiphase correlation between low frequency fluctuations of the resistance R n and the critical current I c has been observed in these junctions, thus showing that both quasiparticles and Cooper pairs flow directly through the same regions of the barrier [24].…”

mentioning

confidence: 99%

Anisotropic distributions of electrical currents in high-T c grain-boundary junctions

et al. 2012

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A decisive role in electrical transport in high T c superconducting materials with anisotropic pairing, like cuprate superconductors [1,2] and Fe based compounds [3][4][5][6], belongs to grain boundaries (GB). Among a variety of possible crystallographic orienta tions of grains forming a boundary, the [001] tilt GB (see Fig. 1a) had been studied the most intensively with an emphases on the effect of order parameter symmetry and the mechanisms of charge transfer across the GB interface [1,2,[7][8][9][10][11][12][13][14][15].Recently, [100] tilt high T c GB junctions with mutually tilted c axis's (see Fig. 1b) have been fabri cated [16][17][18][19][20][21][22][23][24][25] with an order of magnitude lower GB meandering and up to a threefold increase of the I c R n values [16][17][18][19]. A complete antiphase correlation between low frequency fluctuations of the resistance R n and the critical current I c has been observed in these junctions, thus showing that both quasiparticles and Cooper pairs flow directly through the same regions of the barrier [24]. In spite of intensive efforts, the mech anisms of electrical transport through grain bound aries in high T c superconductors are still far from understanding. This is true not only in respect of phys ics of conductivity of GB itself, but also in respect of influence of normal and supercurrent redistribution in the vicinity of GB on their properties.It is well known that strong anisotropy of resistivity of high T c materials must be taken into account during ¶ The article is published in the original.interpretations of electrical data. A simple assumption that electrical resistivity of the material is proportional to the measured resistance with some coefficient of proportionality given by sample geometry may give an incorrect result [26-36].We developed a self consistent method for the calculation of spatial current distributions in high T c grain boundary junctions. It is found that crystallographic anisotropy of high T c superconducting electrodes results in the effects, which previously were not taken into account for interpretations of experimental data. Among them is a significant redistribution of electrical currents in superconducting electrodes in the vicinity of a grain boundary. In particular in the case of [100] tilt bicrystal junctions, this current redistribution results in a substantial focusing to the top or bottom part of a thickness of the grain boundary, depending on "roof" or "valley" type of the grain boundary. This redistribution is accompanied by generation of vortex currents around the grain boundary, which leads to self biasing of grain boundary junctions by magnetic field nucle ated by these vortex currents. It is shown that twinning or variation of geometrical shape of the high T c elec trode may also result in intensive redistribution of electrical currents and nucleation of local magnetic fields inside a high T c superconducting electrodes. Fig. 1. Schematic diagram showing the crystallography of a [001] tilt boundary (a), a [100] tilt b...

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A class of high-T_cY Ba₂Cu₃O_7−xgrain boundary junctions with high-I_cR_nproducts

Cited by 25 publications

References 31 publications

Capacitance of Josephson junctions made on bicrystalline substrates of different geometries

Capacitance of Josephson junctions made on bicrystalline substrates of different geometries

Self-Induced Resonances in Asymmetric Superconducting Quantum Interference Devices

Anisotropic distributions of electrical currents in high-T c grain-boundary junctions

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