## Recent experiments have shown that Josephson junction arrays exhibit coherent large-scale versions of the well-known single junction Shapiro steps. We examine this phenomenon both with and without magnetic field. With some assumptions, a formula for the step width may be derived. We also pre
Fractional giant Shapiro steps in 2D Josephson arrays
โ Scribed by S.P. Benz; M.S. Rzchowski; M. Tinkham; C.J. Lobb
- Book ID
- 104356497
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 376 KB
- Volume
- 165-166
- Category
- Article
- ISSN
- 0921-4526
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โฆ Synopsis
Radio-frequency signals were applied to 1000 by 1000 arrays of SNS Josephson junctions and giant Shapiro steps were observed at voltages 1000 times that expected for a single junction, Vn=nNhv/2e, where N=I000 is the number of junctions in the direction of applied current. For certain perpendicular magnetic fields the field-induced vortices are strongly commensurate with the array and are arranged in superlattices with qxq unit cells. In the presence of these strongly commensurate fields novel fractional giant steps were observed at voltages, Vn=n(N/q)hv/2e, directly related to q. The locking of the motion of the vortex superlattice with the applied rf current is used to explain these novel steps. The possibility of subharmonic fractional steps and preliminary measurements on disordered arrays is discussed.
๐ SIMILAR VOLUMES
We observe giant Shapiro steps in the I-V curves of NxM arrays of SNS Josephson junctions; these steps occur at N times the single junction voltage. Both integer and fractional giant steps are observed as a function of temperature, external magnetic field, and rf current. The fractional steps occur
This paper briefly reviews giant and fractional giant Shapiro steps in Josephson junction arrays. The effects of AC frequency, AC amplitude, finite temperature, disorder, and self-fields due to screening currents, are briefly discussed. A variety of numerical examples are presented for Shapiro steps
We have numerically simulated 20 arrays of resistively shunted Josephson junctions in the presence of commensurate magnetic. fi~lds and alternatin~and direct currents. Fract!onal gi~nt Shapiro steps appear in the simulated current-voltage charactenstIcs at values determmed by the external magnetIc f