Critical-current diffraction patterns of grain-boundary Josephson weak links

R. L. Peterson; J. W. Ekin

doi:10.1103/PhysRevB.42.8014

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Critical-current diffraction patterns of grain-boundary Josephson weak links

R. L. Peterson, J. W. Ekin

DOI 10.1103/PhysRevB.42.8014 · Physical Review B

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Abstract

We discuss the diffraction patterns and other characteristics of the critical current as a function of magnetic field in grain-boundary Josephson barriers. Diffraction patterns occur not just for SIS junctions but for all types of Josephson links, including SNS junctions, which may be present at grain boundaries in high-Tc superconductors. We discuss the generality of the Airy diffraction pattern, which is expected to characterize grain-boundary barriers in bulk material more accurately than the Fraunhofer pattern. The transport critical-current density in many bulk, granular high-Tc superconductors has a power-law dependence on very low magnetic fields, characteristic of averaged diffraction patterns, and cannot be fitted by an exponential magnetic-field dependence, which may result from the material properties of the barriers.