Ga segregation in DyBa2Cu3O7−δ/PrBa2Cu3−xGaxO7−δ/DyBa2Cu3O7−δ ramp-type Josephson junctions

Verbist, K.; Lebedev, Oleg I.; Tendeloo, G. Van; Verhoeven, M.A.J.; Rijnders, Augustinus J.H.M.; Blank, David H.A.; Rogalla, Horst

doi:10.1063/1.118515

Cited by 14 publications

(1 citation statement)

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“…I C R N has been found to scale nearly linearly with L, ranging from 0.8 to 5 mV. Ga-doped junctions appear to be less sensitive to variations of the barrier thickness [259], but problems of diffusion of Ga and formation of a Ga-containing intergrowth in the barrier layer have been demonstrated through TEM analyses [260]. A coherence length of 21 ± 4 nm has been extracted from measurements of the Josephson properties as a function of the barrier thickness for junctions with Y 0.3 Pr 0.7 barriers in the edge geometry [252].…”

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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Section: Barrier Using Perosvkite and Layered Materialsmentioning

confidence: 99%