Internal coherent effects in HTS-normal metal microcontacts

Electrical characteristics of summicron point contacts of YBaCuO-normal metal type with a direct conductivity are measured. For such contacts in a microwave field, a nonstationary Josephson effect is observed which can occur in the region of current concentration not only in the initial weak couplings in YBaCuO but also in the weak couplings of a phase slip center type that are formed due to a considerable current injection (as well as microwave field). The existence of internal weak couplings in the HTSC-electrode contact area is found to cause a narrow minimum of the differential resistance to appear near zero shifts. Moreover, the effect of magnetic flux quantization is observed for separate granules at magnetic fields higher than the first critical one