PROXIMITY HIGH TRANSMITTANCE MICROJUNCTIONS IN PRESENCE OF A MAGNETIC-FIELD

The influence of proximity effects on zero bias conductance (sigma{V = 0}) is investigated in junctions of the type superconductor/normal me tal-constriction-normal metal (S-1/N-1-c-N-2). Such a study is underta ken in some approximations also in the presence of the magnetic field. Zero bias anomalies (ZBA) are determined by the weak coupling nature of the S-1/N-1 interface. Furthermore, the high transmittance of the N -1-c-N-2 interface seems to play a fundamental role in determining the weak dependence of zero bias conductance on the magnetic field, obser ved experimentally in high transmittance microjunctions.