Josephson fluxon flow and phase diffusion in thin-film intrinsic Josephson junctions

Warburton, Paul A.; Kuzhakhmetov, AR; Chana, OS; Burnell, Gavin; Blamire, M. G.; Schneidewind, H.; Koval, Y.; Franz, A; Müller, Paul; Hyland, D.; Dew‐Hughes, D.; Wu, H.; Grovenor, C.R.M.

doi:10.1063/1.1689754

Cited by 17 publications

(7 citation statements)

References 17 publications

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“…A crossover has been demonstrated from wide junction behaviour dominated by Josephson vortex flow to small junction behaviour at a width in the range 0.5 µm < W < 1.5 µm for λ J = 1 µm. Effects of phase diffusion are found in the short regime [306][307][308]. An increase in hysteresis is observed as the junction dimensions are reduced.…”

Section: Intrinsic Stacked Junctionsmentioning

confidence: 89%

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: Intrinsic Stacked Junctionsmentioning

confidence: 89%

Weak links in high critical temperature superconductors

Tafuri¹,

2005

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“…Unfortunately, previous studies of the switching current statistics in Bi-2212 mesas revealed that switching cur- rent histograms of mesas containing several stacked IJJ's may be very unusual. It was reported that histograms of stacked IJJ's may contain multiple peaks [8,13] and appeared to be extremely broad [8,13,14], up to ∼ten times broader than expected. Such anomalous behavior was attributed to the presence of multiple metastable states (fluxon modes), which appear due to coupling of junctions in the stack [8,15].…”

mentioning

confidence: 87%

Probing the intrinsic Josephson coupling potential inBi2Sr2CaCu2O8+
Krasnov
¹
,
Delsing
²

2005
Phys. Rev. B
37
2
24
0
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We study thermal fluctuation phenomena in small Bi-2212 intrinsic Josephson junctions. Being able to measure switching currents of a single intrinsic junction, we observe that it's statistics can be very well described by thermal activation from a periodic Josephson potential with the sinusoidal current-phase relation. This is a direct evidence for the dc-intrinsic Josephson effect and the first unambiguous confirmation of the tunnelling nature of interlayer transport in strongly anisotropic high temperature superconductors. Furthermore, the fluctuation-free critical current, extracted from the analysis of switching current statistics, exhibits a temperature dependence typical for superconductor-insulator-superconductor tunnel junctions. On the other hand, the role of blocking Bi-layers and the nature of interlayer coupling in Bi-2212 is still unclear, partly due to difficulties in analysing intrinsic Josephson data caused by stacking and strong electromagnetic coupling of intrinsic Josephson junctions (IJJ's) [8].The type of Josephson coupling can be deduced from the dependence of the Josephson energy E J on the phase difference ϕ, or, similarly, from the Josephson currentphase relationship I s (ϕ) = (2e/ )∂E J /∂ϕ, which varies from a saw-tooth like for metallic weak links to the sinusoidal for superconductor-insulator-superconductor (SIS) tunnel junctions [9]. The E J (ϕ) determines the junction electrodynamics, which is equivalent to motion of a particle in a "tilted wash-board" potential, created by superposition of the periodic Josephson potential E J (ϕ) and the work done by the current source, −( /2e)Iϕ. At a finite temperature, T , the particle can escape from the potential well as a result of thermal fluctuations, see Fig. 3 a). This corresponds to switching of the junction from the superconducting to the resistive state. The rate of thermal escape [10,11],is a sensitive probe of the E J (ϕ) both via the attempt frequency, ω a , i.e., the frequency of oscillations at the bottom of the potential well, and, particularly, via strong exponential dependence of Γ t on the potential barrier ∆U . Thus, the switching current statistics carries direct information about the shape of E J (ϕ) and, therefore, about the nature of Josephson coupling.In this letter we study the effect of thermal fluctuations in small Bi-2212 intrinsic Josephson junctions. Being able to measure switching currents of a single IJJ in an electrically shielded environment, we observe that it's statistics can be very well, and without fitting parameters, described by thermal activation from the tilted wash-board potential with the sinusoidal current-phase relation. This is a direct evidence for the dc-intrinsic Josephson effect and the first unambiguous confirmation of the tunnelling nature of interlayer transport in Bi-2212. We also demonstrate that thermal fluctuations dramatically affect properties of small IJJ's, resulting in strong suppression of the switching current and unusual temperature dependence in the whole T −range. However, th...

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“…In addition, strong electromagnetic coupling of atomic scale stacked IJJ's in the mesa leads to appearance of metastable fluxon states [49,52] and results in multiple valued critical current [49,51]. It has been reported that switching histograms of IJJ's can be very broad and contain multiple maxima [49,50,51], consistent with frustration caused by the presence of metastable states in long, strongly coupled stacked JJ's [49,51].…”

Section: Collapse In Bi-2212 Intrinsic Josephson Junctionsmentioning

confidence: 99%

Anticorrelation between temperature and fluctuations of the switching current in moderately damped Josephson junctions

2007

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We study the influence of dissipation on the switching current statistics of moderately damped Josephson junctions. Different types of both low-and high-Tc junctions with controlled damping are studied. The damping parameter of the junctions is tuned in a wide range by changing temperature, magnetic field, gate voltage, introducing a ferromagnetic layer or in-situ capacitive shunting. A paradoxical collapse of switching current fluctuations occurs with increasing T in all studied junctions. The phenomenon critically depends on dissipation in the junction and is explained by interplay of two counteracting consequences of thermal fluctuations, which on the one hand assist in premature switching into the resistive state and on the other hand help in retrapping back to the superconducting state. This is one of the rare examples of anticorrelation between temperature and fluctuation amplitude of a physically measurable quantity.

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Josephson fluxon flow and phase diffusion in thin-film intrinsic Josephson junctions

Cited by 17 publications

References 17 publications

Weak links in high critical temperature superconductors

Weak links in high critical temperature superconductors

Probing the intrinsic Josephson coupling potential inBi2Sr2CaCu2O8+
Krasnov
¹
,
Delsing
²

2005
Phys. Rev. B
37
2
24
0
View full text Add to dashboard Cite

Anticorrelation between temperature and fluctuations of the switching current in moderately damped Josephson junctions

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Josephson fluxon flow and phase diffusion in thin-film intrinsic Josephson junctions

Cited by 17 publications

References 17 publications

Weak links in high critical temperature superconductors

Weak links in high critical temperature superconductors

Probing the intrinsic Josephson coupling potential inBi2Sr2CaCu2O8+Krasnov1, Delsing2 2005Phys. Rev. B372240View full textAdd to dashboardCite

Anticorrelation between temperature and fluctuations of the switching current in moderately damped Josephson junctions

Contact Info

Product

Resources

About

Probing the intrinsic Josephson coupling potential inBi2Sr2CaCu2O8+
Krasnov
¹
,
Delsing
²

2005
Phys. Rev. B
37
2
24
0
View full text Add to dashboard Cite