Design and realization of an all <i>d</i>-wave dc π-superconducting quantum interference device

Schulz, Robert; Chesca, Boris; Goetz, B.; Schneider, Claudia; Schmehl, A.; Bielefeldt, H.; Hilgenkamp, H.; Mannhart, J.; Tsuei, C. C.

doi:10.1063/1.125627

Cited by 125 publications

(57 citation statements)

References 17 publications

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“…Since the asymmetryinduced shifts of the I c (Φ ext ) pattern are proportional to the screening, it is vital to design SQUIDs with negligible inductance. Such a problem was solved by Schulz et al [136] using YBCO thin films epitaxially grown on bicrystal and tetracrystal substrates. They obtained, as one can see from Fig.…”

Section: ∼ Tmentioning

confidence: 99%

Paramagnetic Meissner effect and related dynamical phenomena

2003

Physics Reports

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The hallmark of superconductivity is the diamagnetic response to external magnetic field. In striking contrast to this behavior, a paramagnetic response or paramagnetic Meissner effect was observed in ceramic high-Tc and in conventional superconductors. The present review is given on this interesting effect and related phenomena. We begin with a detailed discussion of experimental results on the paramagnetic Meissner effect in both granular and conventional superconductors. There are two main mechanisms leading to the paramagnetic response: the so called d-wave and the flux compression. In the first scenario, the Josephson critical current between two d-wave superconductors becomes negative or equivalently one has a π junction. The paramagnetic signal occurs due to the nonzero spontaneous supercurrent circulating in a loop consisting of odd number of π junctions. In addition to the d-wave mechanism we present the flux compression mechanism for the paramagnetic Meissner effect. The compression may be due to either an inhomogeneous superconducting transition or flux trap inside the giant vortex state. The flux trapping which acts like a total nonzero spontaneous magnetic moment causes the paramagnetic signal. The anisotropic pairing scenario is believed to be valid for granular materials while the flux trap one can be applied to both conventional and high-Tc superconductors. The study of different phenomena by a three-dimensional lattice model of randomly distributed π Josephson junctions with finite self-inductance occupies the main part of our review. By simulations one can show that the chiral glass phase in which chiralities are frozen in time and in space may occur in granular superconductors possessing d-wave pairing symmetry. Experimental attempts on the search for the chiral glass phase are analysed. Experiments on dynamical phenomena such as AC susceptibility, compensation effect, anomalous microwave absorption, aging effect, AC resistivity and enhancement of critical current by external electric fields are considered. These phenomena were studied by Monte Carlo and Langevin dynamics simulations which show satisfactory agreement with experiments. We present a resistively shunted junction model describing rich dynamics of Josephson junction networks.

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Section: ∼ Tmentioning

confidence: 99%

Paramagnetic Meissner effect and related dynamical phenomena

2003

Physics Reports

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“…From this, the intriguing possibility arises to configure superconducting circuits in which part of the Josephson junctions are biased with an additional p-phase shift (p junctions). Examples of circuits incorporating p junctions are corner junctions [3], tricrystal rings [2,4], and dc p SQUIDs [1,6,7]. In these structures, the p junctions are formed by connections between high-T c and low-T c superconductors, or by using grain boundaries prepared by employing specially designed tricrystalline or tetracrystalline substrates.…”

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confidence: 99%

d-Wave–Induced Josephson Current Counterflow inYBa2Cu3O7/
Smilde
¹
,
Ariando
²
,
Blank
³

et al. 2002
Phys. Rev. Lett.
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Well-defined zigzag-shaped ramp-type Josephson junctions between YBa 2 Cu 3 O 7 and Nb have been studied. The magnetic field dependencies of the critical currents provide evidence for d-wave-induced alternations in the direction of the Josephson current between neighboring sides of the zigzag structure. The arrays present controllable model systems to study the influences of p facets in high-angle high-T c grain boundaries. From the characteristics, we estimate a possible imaginary s-wave admixture to the order parameter of the YBa 2 Cu 3 O 7 to be below 1%.

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“…By inserting a 0-junction and a π-junction in the same superconducting loop, π-SQUIDs may be realized. These non-conventional SQUIDs can be fabricated either by exploiting the symmetry properties of d-wave superconductors (Chesca, 1999;Schultz et al, 2000) or by utilizing both s-wave and dwave superconductors (Wollman et al, 1993; Smilde et al, 2004). A π-SQUID can thus be viewed as an elementary cell of a N×(0-π) one-dimensional array of overdamped Josephson junctions shown in fig.…”

Section: Parallel Connections Of N × (0-π) Overdamped Josephson Junctmentioning

confidence: 99%

Effective Models of Superconducting Quantum Interference Devices

Luca¹

2012

Superconductors - Materials, Properties and Applications

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/48483 IntroductionIt is well known that the electrodynamic properties of SQUIDs (Superconducting Quantum Interference Devices) are obtained by means of the dynamics of the Josephson junctions in these superconducting system (Barone & Paternò, 1982;Likharev, 1986;Clarke & Braginsky, 2004). Due to the intrinsic macroscopic coherence of superconductors, r. f. SQUIDs have been proposed as basic units (qubits) in quantum computing (Bocko et al., 1997). In the realm of quantum computing non-dissipative quantum systems with small (or null) inductance parameter and finite capacitance of the Josephson junctions (JJs) are usually considered (Crankshaw & Orlando, 2001). The mesoscopic non-simply connected classical devices, on the other hand, are generally operated and studied in the overdamped limit with negligible capacitance of the JJs and small (or null) values of the inductance parameter. Nonetheless, r. f. SQUIDs find application in a large variety of fields, from biomedicine to aircraft maintenance (Clarke & Braginsky, 2004), justifying actual scientific interest in them.As for d. c. SQUIDs, these systems can be analytically described by means of a single junction model (Romeo & De Luca, 2004). The elementary version of the single-junction model for a d. c. SQUID takes the inductance L of a single branch of the device to be negligible, so that β = LIJ/Φ0 ≈0, where Φ0 is the elementary flux quantum and IJ is the average value of the maximum Josephson currents of the junctions. In this way, the Josephson junction dynamics is described by means of a nonlinear first-order ordinary differential equation (ODE) written in terms of the phase variable φ, which represents the average of the two gauge-invariant superconducting phase differences, φ 1 and φ 2 , across the junctions in the d. c. SQUID. By considering a device with equal Josephsons junction in each of the two symmetric branches, the dynamical equation of the variable φ can be written as follows (Barone & Paternò, 1982): where n is an integer denoting the number of fluxons initially trapped in the superconducting interference loop, τ=2πRIJt/Φ0=t/τ φ , R being the intrinsic resistive junction parameter, ψex=Φex/Φ0 is the externally applied flux normalized to Φ0 and iB= IB/IJ, is the bias current normalized to IJ. In what follows we shall consider zero-field cooling conditions, thus taking n=0. Eq. (1) is similar to the non-linear first-order ODE describing the dynamics of the gauge-invariant superconducting phase difference across a single overdamped JJ with field-modulated maximum current IJF (IJF=|cosπψex|) in which a normalized bias current iB/2 flows. This strict equivalence comes from the hypothesis that the total normalized flux ψ=Φ/Φ0 linked to the interferometer loop can be taken to be equal to ψex. However, being ( ) 12 ,we may say that the above hypothesis may be stated merely by means of the following identity: β=0. Therefore, for finite values of the parameter β, Eq....

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Design and realization of an all d-wave dc π-superconducting quantum interference device

Cited by 125 publications

References 17 publications

Paramagnetic Meissner effect and related dynamical phenomena

Paramagnetic Meissner effect and related dynamical phenomena

d-Wave–Induced Josephson Current Counterflow inYBa2Cu3O7/
Smilde
¹
,
Ariando
²
,
Blank
³

et al. 2002
Phys. Rev. Lett.
Self Cite
129
9
120
0
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Effective Models of Superconducting Quantum Interference Devices

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Design and realization of an all d-wave dc π-superconducting quantum interference device

Cited by 125 publications

References 17 publications

Paramagnetic Meissner effect and related dynamical phenomena

Paramagnetic Meissner effect and related dynamical phenomena

d-Wave–Induced Josephson Current Counterflow inYBa2Cu3O7/Smilde1, Ariando2, Blank3 et al. 2002Phys. Rev. Lett.Self Cite12991200View full textAdd to dashboardCite

Effective Models of Superconducting Quantum Interference Devices

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d-Wave–Induced Josephson Current Counterflow inYBa2Cu3O7/
Smilde
¹
,
Ariando
²
,
Blank
³

et al. 2002
Phys. Rev. Lett.
Self Cite
129
9
120
0
View full text Add to dashboard Cite