Normal-distribution-function-shaped Josephson tunnel junctions

We have investigated the magnetic field dependence of the Josephson tunnel junctions whose shape is defined with a normal-distribution function. It wa s revealed that the normal-distribution-shaped Josephson tunnel junctions s how an exponential decay and no side lobes of the Josephson current as the external magnetic field is increased. This behavior was confirmed experimen tally by using the Nb/AlOx/Nb tunnel junctions with a Josephson critical cu rrent density of J(c)=50 A/cm(2), and an area of 10 000 mum(2) correspondin g to the "small" junction region. Normal-distribution junctions should have a potential for wide applications to photon detection since the external m agnetic field to suppress the Josephson current can be lowered to less than one tenth that of other junctions reported. (C) 2000 American Institute of Physics. [S0003-6951(00)04247-9].