Electric Properties of YBCO/PBCO/YBCO Junctions

Hashimoto, Tatsunori; Sagoi, Masayuki; Mizutani, Y.; Yoshida, Jiro; Mizushima, Koichi

doi:10.1007/978-4-431-68195-3_191

Cited by 7 publications

(10 citation statements)

References 8 publications

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“…Experimental measurements shows variable-range hopping transport for bulk PBCO samples [13] and semiconducting-like dependence of the YBCO/PBCO/YBCO junction resistance at barrier thicknesses L -100 nm [13]. The value of the pair-breaking parameter z, *l/nT, is also in qualitative agreement with the estimate of the spin-flip scattering time for PBCO.…”

Section: Introductionsupporting

confidence: 69%

Transport processes and reduction of I/sub c/R/sub n/ product in YBa/sub 2/Cu/sub 3/O/sub x//PrBa/sub 2/Cu/sub 3/O/sub x//YBa/sub 2/Cu/sub 3/O/sub x/ ramp-type Josephson junctions

Boguslavskij

Gao

Rijnders

et al. 1993

IEEE Trans. Appl. Supercond.

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The mechanisms of the current passage and the reasons of IC& product reduction of the YBCO/PBCO/YBCO ramp-type junctions are analyzed. At PBCO barrier thicknesses L=8-20 nm the junction characteristics are determined by the thickness of the PBCO barrier and its nature. The boundary resistance and depression of the YBCO superconducting parameters near the interface do not strongly affect the junction parameters. The behavior of the YBCOPBCOKBCO junctions can not be described by simple SNS weak-link or SIS tunnel models. A strong pair-breaking effect and an one-center inelastic tunneling process are taken into account to explain the Josephson and normal state characteristics of these junctions.

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Section: Introductionsupporting

confidence: 69%

Transport processes and reduction of I/sub c/R/sub n/ product in YBa/sub 2/Cu/sub 3/O/sub x//PrBa/sub 2/Cu/sub 3/O/sub x//YBa/sub 2/Cu/sub 3/O/sub x/ ramp-type Josephson junctions

Boguslavskij

Gao

Rijnders

et al. 1993

IEEE Trans. Appl. Supercond.

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“…For instance, bulk PBCO is reported to behave like a variable-range hopping conductor caused by the relatively high density of localized states, and PBCO barriers may allow the study of effects of two localized states in an inelastic tunnelling process [261,262]. A-axis YBCO-PBCO-YBCO junctions (meant to exploit the longer in-plane coherence lengths) were made in the early stages [263,264]. More recently they have also been made on (100) LaSrGaO 4 [265] and vicinal (001) LaAlO 3 -SrAl 0.5 Ta 0.5 O 3 substrates [266] with spreads in I C and R N of 11% and 8.8%, respectively.…”

Section: Barrier Using Perosvkite and Layered Materialsmentioning

confidence: 99%

Weak links in high critical temperature superconductors

Tafuri¹,

2005

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The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductorbarrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-T C superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence of d-wave pairing for different types of barriers.

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“…In this experiment, the thickness of the PBCO interlayer of the junction is as long as hundreds Å which is much larger than the high-T c superconducting correlation length by an order of magnitude and thus the Cooper pairs cannot directly tunnel the junction. These longrange proximity effects have been observed in many experiments on HTS junctions [10][11][12][13] and considered as a characteristic of SN long S junctions. Thus the experimental results may be explained by calculating the currents of the SN long S loop as a function of the threading external flux.…”

mentioning

confidence: 81%