Manifestation of π-contacts in magnetic field dependence of [formula omitted] characteristics for proximity-type 2D Josephson junction array

Abstract

Results on the temperature and magnetic field dependence of current–voltage characteristics (CVC) are presented for SNS-type 2D ordered array of Nb–Cu 0.95Al 0.05–Nb junctions. The critical current I C ( T , H ) and the power exponent a ( T , H ) = 1 + Φ 0 I C ( T , H ) / 2 k B T of the nonlinear CVC law V = R [ I − I C ( T , H ) ] a ( T , H ) are found to have a maximum at non-zero value of applied magnetic field H p = 225 Oe , which is attributed to manifestation of π-type Josephson contacts in our sample.