Excess current in high-Tc Josephson junction with thin PrBa2Cu3Oy barrier layer

The temperature dependence of excess current in the ramp-edge YBa 2 Cu 3 O y /PrBa 2 Cu 3 O y /YBa 2 Cu 3 O y Josephson junctions has been studied. The experimental results indicated that excess current may be caused by Andreev reflection at the SN interfaces of SNS junctions. It was found that the temperature dependence of excess current is the same as that of order parameter at the N side of SN interface. This is in agreement with the prediction of theory. The amplitude of the excess current is the same order as that of critical current.