PROPERTIES OF HTS STEP-EDGE SNS JUNCTIONS

The critical current and current-voltage characteristics of step-edge HTS SNS junctions are discussed theoretically. In accordance with the experimental data it is assumed that the current transport through bot h NS interfaces takes place In ab-direction. In the bottom interface ( (001) surface of YBCO) the ab-coupling may occur due to atomic steps w hich play a role of constrictions for the current flam. Therefore the contact is modelled las SNS structure with system of constrictions loc ated at both interfaces. The IcRN product anal the excess current I-cx are calculated as a function of temperature, interface transparency a nd N layer thickness. It is shown that in accordance with the experime ntal data the I-cx and I-c are of the same order of magnitude in a bro ad parameter range.