Novel magnetoinductance effects in Josephson junction arrays: A single-plaquette approximation (original) (raw)
Related papers
Journal of Experimental and Theoretical Physics Letters, 2004
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).
Reentrant ac Magnetic Susceptibility in Josephson-Junction Arrays
Physical Review Letters, 1997
The paramagnetic Meissner effect ͑PME͒ measured in high-T C granular superconductors has been attributed to the presence of junctions between the grains. Here we present measurements of complex ac magnetic susceptibility from two-dimensional arrays of conventional ͑non-͒ Nb/Al/AlOx/Nb Josephson junctions. We measured the susceptibility as a function of the temperature T, the ac amplitude of the excitation field h ac and the external magnetic field H dc. The experiments show a strong paramagnetic contribution from the multijunction loops, which manifests itself as a reentrant screening at low temperature, for values of h ac higher than 50 mOe. A highly simplified model, based on a single loop containing four junctions, accounts for this paramagnetic contribution and the range of parameters in which it appears. This model offers an alternative explanation of PME that does not involve junctions. ͓S0163-1829͑99͒02234-1͔
Physical review, 1999
The paramagnetic Meissner effect ͑PME͒ measured in high-T C granular superconductors has been attributed to the presence of junctions between the grains. Here we present measurements of complex ac magnetic susceptibility from two-dimensional arrays of conventional ͑non-͒ Nb/Al/AlOx/Nb Josephson junctions. We measured the susceptibility as a function of the temperature T, the ac amplitude of the excitation field h ac and the external magnetic field H dc. The experiments show a strong paramagnetic contribution from the multijunction loops, which manifests itself as a reentrant screening at low temperature, for values of h ac higher than 50 mOe. A highly simplified model, based on a single loop containing four junctions, accounts for this paramagnetic contribution and the range of parameters in which it appears. This model offers an alternative explanation of PME that does not involve junctions. ͓S0163-1829͑99͒02234-1͔
Magnetic field induced charging effects in Josephson junction arrays
Journal de Physique I, 1997
A magnetic field induced electric polarization and the corresponding change of an effective junction capacitance are considered within a 3D model of disordered Josephson junction arrays. At some threshold field (near the Josephson network critical field), the effective junction charge and the related capacitance are shown to reach a maximum and to change a sign, respectively. A possibility to observe the predicted effects in artificially prepared arrays of superconducting grains is discussed.
Physical Review B, 1999
The dynamical vortex response of a two-dimensional array of the resistively shunted Josephson junctions in a perpendicular magnetic field is inferred from simulations. It is found that, as the magnetic field is increased at a fixed temperature, the response crosses over from normal to anomalous, and that this crossover can be characterized by a single dimensionless parameter. It is described how this crossover should be reflected in measurements of the complex impedance for Josephson junction arrays and superconducting films.
Journal of Low Temperature Physics, 2005
The role of the external magnetic field in performance specialty of the hightemperature superconducting (HTS) Josephson junction array (JJA): HTS Y Ba 2 Cu 3 O 7−0.05 bicrystal JJA with 180 junctions, is considered. The junctions are created on the yttrium-stabilized zirconium (fianite) substrate with the bicrystal grain boundary. The experimental confirmation of the current density changes under the influence of the external DC magnetic field is obtained. The dependence of current density on the penetrated magnetic field is investigated. The optimal shielding factor needed to obtain high supercurrents in considered system is determined.
Physics Letters A, 2001
A comparative study of the magnetic remanence exhibited by tridimensional Josephson junction arrays in response to an excitation with an AC magnetic field is presented. The observed temperature behavior of the remanence curves for disordered arrays fabricated from three different materials (Nb, YBa 2 Cu 3 O 7-δ and La 1.85 Sr 0.15 CuO 4-δ ) is found to follow the same universal law (based on the explicit temperature expressions for the activation energy and the inductance-dominated contribution to the magnetization of the array within the framework of the phase-slip model) regardless of the origin of the superconducting electrodes of the junctions which form the array.
Flux flow and vortex tunneling in two-dimensional arrays of small Josephson junctions
Physical review. B, Condensed matter, 1996
We have measured the temperature dependence and magnetic field dependence of the zero-bias resistance (R 0 ) as well as the current-voltage (I-V) characteristics for several two-dimensional arrays of small aluminum Josephson junctions. R 0 (T) decreases with decreasing temperature, which can be described in terms of two types of vortex motion: flux, flow, and vortex tunneling. At temperatures higher than the Kosterlitz-Thouless transition temperature (TϾT c ) or at a bias current greater than the current corresponding to the onset of the nonlinear I-V characteristics (IϾI d ), the effective damping resistance which characterizes flux-flow motion is found to be approximately equal to the junction normal-state resistance R N . At low temperatures and at small bias current, R 0 is temperature independent and remains finite down to our minimum attainable temperature. This finite resistance is found to be dependent on the array size as well as the junction parameters.
New Developments in Josephson Junctions Research
DC magnetic moments of SIS and SNS type Josephson 1 junction arrays E.V. Matizen and S.M. Ishikaev Experimental and theoretical study on 2D ordered and 25 3D disordered SIS type arrays of Josephson junctions F.M. Araujo-Moreira and S. Sergeenkov Magnetization states in annular π-junction arrays 45 G. Rotoli Josephson junction as a prototype for synchronization 83 of nonlinear oscillators G. Filatrella
Superconducting and insulating behavior in one-dimensional Josephson junction arrays
Experiments on one-dimensional small capacitance Josephson Junction arrays are described. The arrays have a junction capacitance that is much larger than the stray capacitance of the electrodes, which we argue is important for observation of Coulomb blockade. The Josephson energy can be tuned in situ and an evolution from Josephson-like to Coulomb blockade behavior is observed. This evolution can be described as a superconducting to insulating, quantum phase transition. In the Coulomb blockade state, hysteretic current-voltage characteristics are described by a dynamic model which is dual to the resistively shunted junction model of classical Josephson junctions.