Observation of Josephson Junctionlike Behavior in Single-Crystal (Bi, Pb)2Sr2CaCu2Oy

Oya, Gin‐ichiro; Aoyama, Nagisa; Irie, Atsushi; Kishida, Satoru; Tokutaka, Heizō

doi:10.1143/jjap.31.l829

Cited by 186 publications

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“…We discuss reproducible gap-like features in the current-voltage characteristics of the samples at high bias. [1,2]. A BSCCO single crystal in the c-axis direction can thus be viewed as a large array of very thin (1.5 nm) intrinsic Josephson junctions (IJJs) in series.…”

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confidence: 99%

Single intrinsic Josephson junction with double-sided fabrication technique

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Torstensson

Yurgens

et al. 2006

Applied Physics Letters

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We make stacks of intrinsic Josephson junctions (IJJs) imbedded in the bulk of very thin (d ≤ 100 nm) Bi2Sr2CaCu2O8+x single crystals. By precisely controlling the etching depth during the double-sided fabrication process, the stacks can be reproducibly tailor-made to be of any microscopic height (0 − 9 nm < d), i.e. enclosing a specified number of IJJ (0 − 6), including the important case of a single junction. We discuss reproducible gap-like features in the current-voltage characteristics of the samples at high bias. [1,2]. A BSCCO single crystal in the c-axis direction can thus be viewed as a large array of very thin (1.5 nm) intrinsic Josephson junctions (IJJs) in series. At present, this is perhaps the only reliable way to obtain HTS SIS junctions. These junctions appear to have high potential for high-frequency applications like heterodyne receivers and quantum voltage standards [3,4].It is difficult to isolate and study individual IJJ. Most of applications and research on IJJs use therefore stacks containing many junctions. The stacks can be formed either on the surfaces of single crystals (mesas) or etched out in the middle of BSCCO whiskers using focussed ion beams [5]. Earlier we developed a method for making a single intrinsic Josephson junction (SIJJ) enclosed in a U-shaped mesa structure [6]. An effective SIJJ could be seen in the 4-probe measurements on such a mesa. However, extra junctions under the electrodes can give rise to unwanted local heating [7,8].In this letter, we report on reproducible fabrication of uniform stacks formed inside the very thin (d ∼ 100 nm) pieces of BSCCO single crystals by using a double-sided etching technique [9]. The number of junctions in the stacks can be tailor-made to any small number N < 10 including the important case of N = 1 (a single-junction stack). As the stacks are imbedded in the superconducting material, i.e. there are no direct resistive contacts to them, heating effects can be minimized in such stacks allowing the genuine current-voltage (I-V) characteristics to be traced out. Devices like SQUIDs are feasible to make using the developed technique.The stack-fabrication routines start with evaporation of an Au thin film on a freshly cleaved crystal glued onto a sapphire substrate using polyimide. Using the conventional photolithography and Ar-ion etching, a bow-tieshaped mesa with a micro-bridge in the center is formed on the crystal. The overall thickness of this mesa d is typically about 100 nm which is controlled by etching time and rate. Then, a 40 nm d/2 deep slit is made across the bridge. In the next step, we flip the sample and glue it onto another sapphire substrate, sandwiching the single crystal between the two substrates. Separating the substrates cleaves the single crystal into two pieces, one with the mesa being flipped upside down and glued to the second substrate. We subsequently remove all material but the mesa by iteratively cleaving the former with the aid of Scotch tape and inspecting the resulting sample in optical microscope. A ne...

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confidence: 99%

Single intrinsic Josephson junction with double-sided fabrication technique

You

Torstensson

Yurgens

et al. 2006

Applied Physics Letters

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“…As we expected the slopes of the branches are getting close to the slope of the outermost branch, but this approaching is decreased with increase in Using the equations of CCJJ model [7] we obtain the analytical expression for the α -dependence of the slope n, taking into account the distribution of R-and O-junctions in the stack. For example, 2 …”

Section: Model and Numerical Resultsmentioning

confidence: 99%

“…Different type of couplings between junctions, like inductive coupling in the presence of magnetic field [1], capacitive [2]- [3], charge-imbalance [4] and phonon [5] couplings determine a variety of currentvoltage characteristics (IVC) observed in high temperature superconductors ( HTSC). In [6] has been stressed that capacitive coupling takes various values in HTSC and layered organic superconductors, that is, the capacitive coupling is tunable in these systems.…”

Section: Introductionmentioning

confidence: 99%

Influence of coupling parameter on current–voltage characteristics of intrinsic Josephson junctions in high-Tc superconductors

Shukrinov

Mahfouzi

2006

Physica C: Superconductivity and its Applications

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“…As an example, we set the α t o1s o that the corresponding configuration Γ is (1, 1, 1.5, 1, 1). The I-V characteristics calculated for χ 3 respectively. Figure 11 leads us a same conclusion mentioned above such that due to the decreasing the value of χ 3 (d F ), (I) the I-V characteristic of 3@5 junction including the F-layer gradually changes, but those of 1@5 and 2@5 junctions without the F-layer well remain the same, and (II) Shapiro steps are clearly found in 1@5 and 2@5 junctions, but the height of the Shapiro step found in 3@5 junction decreases and reaches to zero when χ 3 (d F )=0.…”

Section: Effect Of Ferromagnetic Layermentioning

confidence: 99%

“…[2][3][4][5][6][7][8] The stacking structure of IJJs along the crystallographic c-axis can be made naturally,s o that these natural super-lattices can be regarded as a stack of good quality Josephson devices made under the atomic-scale. This is just a reason why the studies of the current flow along the c-axis have been done extensively for the high-T c superconductors.…”

Section: Introductionmentioning

confidence: 99%

Shapiro Steps in BSCCO Intrinsic Josephson Junctions

Kitamura¹

2012

Superconductors - Properties, Technology, and Applications

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8www.intechopen.com 2 Will-be-set-by-IN-TECH BSCCO consists of a stack of SIS-type IJJs, so it is expected that the BSCCO should be regarded as a good sample to study the fluxon dynamics in the SIS Josephson junctions. Actually, there are many excellent works for the effect of magnetic field on the BSCCO IJJs. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] It is sure that a pioneering work done by Sakai, Bodin and Pedersen(SBP) [20] is the starting point to understand the fluxon dynamics in BSCCO IJJs with a stacking structure.We adopt here a unified theory proposed by Machida and Sakai (MS) [29], which includes both the electric and magnetic field couplings between neighboring IJJs in multistacked structure. The MS-unified theory is a further extension of the model proposed by Sakai, Bodin and Pedersen (SBP).[20] Present paper is mainly based on my previous jobs. [35,36] TheoryLet us consider a stacked system consisting of N-identical SIS-Josephson junctions such as IJJs in BSCCO high-T c superconductors, and set spacial coodinates x, y and z parallel to a, b and c axes of a BSCCO single crystal. If the external magnetic induction B ext is selected parallel to y-axis, i.e., B ext =(0, B ext ,0), and the spacial variation of the gauge-invariant phase difference ϕ ℓ for the ℓ-th SIS Josephson junction is assumed as a function of only x, then the ϕ ℓ (x, t) as a function of x and real time t satisfies a following coupled sine-Gordon(CSG) equation with a matrix form.[29]where λ J is the Josephson penetration depth given by Φ 0 /2πµ 0 d ′ L J c using a flux quantum Φ 0 , the vacuum permeability µ 0 and the critical current density J c . The Σ c and Σ L are matrices describing the electric and magnetic interactions between neighboring Josephson junctions and are written aswhere the coupling constants Σ c and Σ L are given by [29]The d ′ c and d ′ L are the effective electric and magnetic thickness given byusing electrode thickness w and barrier thickness d. The λ e and λ L are the Debye screening length and the London penetration depth, respectively. The J ℓ (x, t) in Eq.(2) is the current defined by j

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Observation of Josephson Junctionlike Behavior in Single-Crystal (Bi, Pb)₂Sr₂CaCu₂O_y

Cited by 186 publications

References 13 publications

Single intrinsic Josephson junction with double-sided fabrication technique

Single intrinsic Josephson junction with double-sided fabrication technique

Influence of coupling parameter on current–voltage characteristics of intrinsic Josephson junctions in high-Tc superconductors

Shapiro Steps in BSCCO Intrinsic Josephson Junctions

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