Magnetic properties of two-dimensional SNS-type Josephson junction arrays

Ishikaev, S. M.; Matizen, É. V.; Ryazanov, V. V.; Oboznov, V. A.

doi:10.1134/1.1514760

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…An avalanche character of flux motion was observed at temperatures at which the size of the fluxons did not exceed the size of the cell, that is, for discrete vortices. On the other hand, using a similar technique, magnetic flux avalanches were not observed in SNS-type proximity arrays (Ishikaev et al 2002) In this section we present experimental evidence for manifestation of novel geometric effects in magnetic response of high-quality ordered 2D-JJA (Sergeenkov and Araujo-Moreira 2004). By improving resolution of home-made mutual-inductance measurements technique described in the beginning of this article, a pronounced step-like structure (with the number of steps n = 4 for all AC fields) has been observed in the temperature dependence of AC susceptibility in artificially prepared two-dimensional Josephson Junction Arrays (2D-JJA) of unshunted Nb-AlO x -Nb junctions with 30…”

Section: Manifestation Of Geometry Imposed Quantization Effects Inmentioning

confidence: 96%

“…An avalanche character of flux motion was observed at temperatures at which the size of the fluxons did not exceed the size of the cell, that is, for discrete vortices. On the other hand, using a similar technique, magnetic flux avalanches were not observed in superconductor-normal metal-superconductor (SNS)-type proximity arrays (Ishikaev et al 2002) despite a sufficiently high value of the inductance L related critical parameter β L = 2π L I C / 0 needed to satisfy the observability conditions of SOC. Instead, the observed quasi-hydrodynamic flux motion in the array was explained by the considerable viscosity characterizing the vortex motion through the Josephson junctions.…”

Section: Manifestation Of Geometry Imposed Quantization Effects In Th...mentioning

confidence: 99%

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Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays

Araújo‐Moreira¹,

Sergeenkov²

2008

Supercond. Sci. Technol.

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Abstract. In this review, we report on different phenomena related to the magnetic properties of artificially prepared highly ordered (periodic) two-dimensional Josephson junction arrays (2D-JJA) of both shunted and unshunted Nb-AlO x -Nb tunnel junctions. By employing mutual-inductance measurements and using a high-sensitive home-made bridge, we have thoroughly investigated (both experimentally and theoretically) the temperature and magnetic field dependence of complex AC susceptibility of 2D-JJA. After brief description of the measurements technique and numerical simulations method, we proceed to demonstrate that the observed dynamic reentrance (DR) phenomenon is directly linked to the value of the Stewart-McCumber parameter β C . By simultaneously varying the inductance related parameter β L , we obtain a phase diagram β C -β L (which demarcates the border between the reentrant and non-reentrant behavior) and show that only arrays with sufficiently large value of β C will exhibit the DR behavior. The second topic of this review is related to the step-like structure (with the number of steps n = 4 corresponding to the number of flux quanta that can be screened by the maximum critical current of the junctions) which has been observed in the temperature dependence of AC susceptibility in our unshunted 2D-JJA with β L (4.2K) = 30 and attributed to the geometric properties of the array. The steps are predicted to manifest themselves in arrays with β L (T) matching a "quantization" condition β L (0)=2π(n+1).In conclusion, we demonstrate the use of the scanning SQUID microscope for imaging the local flux distribution within our unshunted arrays.

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Section: Manifestation Of Geometry Imposed Quantization Effects Inmentioning

confidence: 96%

“…An avalanche character of flux motion was observed at temperatures at which the size of the fluxons did not exceed the size of the cell, that is, for discrete vortices. On the other hand, using a similar technique, magnetic flux avalanches were not observed in superconductor-normal metal-superconductor (SNS)-type proximity arrays (Ishikaev et al 2002) despite a sufficiently high value of the inductance L related critical parameter β L = 2π L I C / 0 needed to satisfy the observability conditions of SOC. Instead, the observed quasi-hydrodynamic flux motion in the array was explained by the considerable viscosity characterizing the vortex motion through the Josephson junctions.…”

Section: Manifestation Of Geometry Imposed Quantization Effects In Th...mentioning

confidence: 99%

Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays

Araújo‐Moreira¹,

Sergeenkov²

2008

Supercond. Sci. Technol.

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“…An avalanche character of flux motion was observed at temperatures at which the size of the fluxons did not exceed the size of the cell, that is, for discrete vortices. On the other hand, using a similar technique, magnetic flux avalanches were not observed in SNS-type proximity arrays [8] despite a sufficiently high value of the inductance L related critical parameter β L = 2πLI C /Φ 0 needed to satisfy the observability conditions of SOC. Instead, the observed quasi-hydrodynamic flux motion in the array was explained by the considerable viscosity characterizing the vortex motion through the Josephson junctions.…”

mentioning

confidence: 99%

Manifestation of geometric effects in temperature behavior of ac magnetic response of Josephson junction arrays

Sergeenkov

Araújo‐Moreira

2004

Jetp Lett.

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By improving resolution of home-made mutual-inductance measurements technique, a pronounced step-like structure (with the number of steps n = 4 for all AC fields) has been observed in the temperature dependence of AC susceptibility in artificially prepared two-dimensional Josephson Junction Arrays (2D-JJA) of unshunted N b − AlOx − N b junctions with βL(4.2K) = 30. Using a single-plaquette approximation of the overdamped 2D-JJA model, we were able to successfully fit our data assuming that steps are related to the geometric properties of the plaquette. The number of steps n corresponds to the number of flux quanta that can be screened by the maximum critical current of the junctions. The steps are predicted to manifest themselves in arrays with the inductance related parameter βL(T ) matching a "quantization" condition βL(0) = 2π(n + 1). PACS: 74.25.Ha, 74.50.+r, 74.80.Bj 1. Introduction. Many unusual and still not completely understood magnetic properties of Josephson Junction Arrays (JJAs) continue to attract attention of both theoreticians and experimentalists alike (for recent reviews on the subject see, e.g. [1,2,3,4] and further references therein). In particular, among the numerous spectacular phenomena recently discussed and observed in JJAs we would like to mention the dynamic temperature reentrance of AC susceptibility [2] (closely related to paramagnetic Meissner effect [3]) and avalanche-like magnetic field behavior of magnetization [4,5] (closely related to self-organized criticality (SOC) [6,7]). More specifically, using highly sensitive SQUID magnetometer, magnetic field jumps in the magnetization curves associated with the entry and exit of avalanches of tens and hundreds of fluxons were clearly seen in SIS-type arrays [5]. Besides, it was shown that the probability distribution of these processes is in good agreement with the SOC theory [7]. An avalanche character of flux motion was observed at temperatures at which the size of the fluxons did not exceed the size of the cell, that is, for discrete vortices. On the other hand, using a similar technique, magnetic flux avalanches were not observed in SNS-type proximity arrays [8] despite a sufficiently high value of the inductance L related critical parameter β L = 2πLI C /Φ 0 needed to satisfy the observability conditions of SOC. Instead, the observed quasi-hydrodynamic flux motion in the array was explained by the considerable viscosity characterizing the vortex motion through the Josephson junctions.

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“…Usually, due to inevitable distribution of critical currents and sizes of the individual junctions, a grain-boundary induced Josephson network in polycrystalline materials manifests itself in a rather incoherent way, making it virtually impossible for applications. That is why, ordered artificially prepared (hence more costly) Josephson junction arrays (JJAs) are used instead to achieve the expected performance [9,10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

Unusually strong coherent response from grain-boundary Josephson network in polycrystalline Pr x Y1 − x Ba2Cu3O7 − δ

et al. 2009

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By applying a highly sensitive homemade AC susceptibility technique to P rxY1−xBa2Cu3O 7−δ polycrystals (with x = 0.0, 0.1 and 0.3), we observed very sharp Fraunhofer type low-field periodic oscillations of the real part of the AC susceptibility which were attributed to Josephson vortices penetrating intergranular regions of grain-boundary Josephson network in our samples. Assuming the Lorentz type distribution of single-junction contact areas, we were able to successfully fit the experimental data.

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Magnetic properties of two-dimensional SNS-type Josephson junction arrays

Cited by 5 publications

References 11 publications

Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays

Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays

Manifestation of geometric effects in temperature behavior of ac magnetic response of Josephson junction arrays

Unusually strong coherent response from grain-boundary Josephson network in polycrystalline Pr x Y1 − x Ba2Cu3O7 − δ

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Magnetic properties of two-dimensional SNS-type Josephson junction arrays

Cited by 5 publications

References 11 publications

Dynamical reentrance and geometry imposed quantization effects in Nb–AlOx–Nb Josephson junction arrays

Dynamical reentrance and geometry imposed quantization effects in Nb–AlOx–Nb Josephson junction arrays

Manifestation of geometric effects in temperature behavior of ac magnetic response of Josephson junction arrays

Unusually strong coherent response from grain-boundary Josephson network in polycrystalline Pr x Y1 − x Ba2Cu3O7 − δ

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Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays

Dynamical reentrance and geometry imposed quantization effects in Nb–AlO_x–Nb Josephson junction arrays