YBa2Cu3O7−δ/NdBa2Cu3O7−δ/YBa2Cu3O7−δ edge junctions and SQUIDS

Oh, B.; Choi, Yong-Bin; Moon, S. H.; Kim, H. T.; Min, Byoung‐Chul

doi:10.1063/1.117536

Cited by 13 publications

(4 citation statements)

References 10 publications

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“…NdBa 2 Cu 3 O 7−x (NBCO) barriers of variable thickness (10-30 nm) have also been used in a ramp-edge geometry [269]. These junctions give ξ = 4 nm at T = 77 K, but a transition to flux-flow like behaviour occurred far above the normal transition temperature of the NBCO barrier, limiting the performances of the junctions.…”

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%

Weak links in high critical temperature superconductors

Tafuri¹,

2005

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“…The I-V characteristic of the junctions can be well described by resistively shunted junction (RSJ) model. 43 The more ideal behavior for the modified N-layer suggests that problems at the junction area attributed in the past to oxygen loss may be minimized for the new system. Figure 12(b) shows the voltage modulation versus magnetic flux characteristics of the same dc SQUID of Fig.…”

Section: F Utilization Of New Materials For Preparation Of Functionamentioning

confidence: 99%

Development of a reliable materials base for superconducting electronics

Zhou

McDevitt

et al. 1997

J. Mater. Res.

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Careful studies of the corrosion, redox, galvanic, and oxygen evolution/uptake reactions associated with YBa 2 Cu 3 O 72d and related compounds have been completed. These studies have led to an understanding of the many factors that contribute to the poor material characteristics exhibited by these popular high-T c phases. With knowledge of the structure-reactivity relationships, a powerful crystal engineering approach has been developed that is capable of producing cation substituted versions of YBa 2 Cu 3 O 72d ; the resulting compounds therefrom produced exhibit markedly improved processability, oxygen stability, and durability characteristics. These materials have been combined in thin film structures so as to make prototype SNS junctions and SQUID sensors which exhibit promising device performance characteristics.

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“…In addition, the Jc of this material is large at high appllied magnetic field, which is important to small device appliications as well as superconducting wires [ 11-[4]. NlBCO is also a good candidate as a barrier in SNS junclions, since it has a large Tc variation from zero to 90 K depending on x (the mixing rate of Nd/l3a) and 6 (oxygen amount), while it has the same structure as YBCO with fairly goodl lattice matches [5]- [7]. This may be due to the large solubility of Nd in the Ba site, since the two atoms have similar radii.…”

Section: Introductionmentioning

confidence: 99%

Superconducting NdBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin films prepared by the laser ablation method

Moon

1997

IEEE Trans. Appl. Supercond.

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Albstract-NdBa2Cu3O,-+NBCO) thin films were deposited on (100) SrTiO,(STO) substrates by the laser ablation method. The transition temperature of thin films was very sensitive to the deposition parameters such as substrate temperature, chamber pressure, and the distance between target and substrate. Thin film; of T, -93 K were obtained when we deposited at 770 "C and 800 mTorr of oxygen pressure. The NEICO thin films were grown epitaxially with c-axis preferred orientation. The critical current density of the thin films was -1 x lo6 Akm2 at 77 K.We have also studied the surface morphology with AFM, and the typical smoothness is -3 nm.

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YBa2Cu3O7−δ/NdBa2Cu3O7−δ/YBa2Cu3O7−δ edge junctions and SQUIDS

Cited by 13 publications

References 10 publications

Weak links in high critical temperature superconductors

Weak links in high critical temperature superconductors

Development of a reliable materials base for superconducting electronics

Superconducting NdBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin films prepared by the laser ablation method

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