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Switching functions using a parallel connection of conventional-type and πtype junctions have been investigated. Both junctions consist of Nb/Au/YBa[sub 2]Cu[sub 3]O[sub 7]-δ Josephson junctions on YBa[sub 2]Cu[sub 3]O[sub 7]-δ edges, whose faces are (110) and (100). The modulation patterns of critical currents in low magnetic fields indicate that the d-wave component is dominant: the (100) junctions exhibit the conventional type, but the (110) junctions the π type. Superconducting current path is alternated between the conventional junction and the π junction by applied magnetic fields using these anisotropic magnetic field dependences of the critical current. [ABSTRACT FROM AUTHOR]

Demonstrates the anisotropic Josephson effect in all (103)-oriented junctions consisting of YBa[sub 2]Cu[sub 3]O[sub 7-delta]/PrBa[sub 2]Cu[sub 3]O[sub 7-delta']/YBa[sub 2]Cu[sub 3]O[sub 7-delta] films. Characteristics of the junction; Use of the junction isolation technology; Exhibition of anisotropic Fraunhofer interference patterns.

We have investigated the magnetic field dependence of the Josephson tunnel junctions whose shape is defined with a normal-distribution function. It was revealed that the normal-distribution-shaped Josephson tunnel junctions show an exponential decay and no side lobes of the Josephson current as the external magnetic field is increased. This behavior was confirmed experimentally by using the Nb/AlO[sub x]/Nb tunnel junctions with a Josephson critical current density of J[sub c]=50 A/cm[sup 2], and an area of 10 000 μm[sup 2] corresponding to the "small" junction region. Normal-distribution junctions should have a potential for wide applications to photon detection since the external magnetic field to suppress the Josephson current can be lowered to less than one tenth that of other junctions reported. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]