Frequency transformation at quasi-particle non-linearity of Nb-Al2O3-Nb type tunnel transformations

The purpose of the study is the investigation of frequency transformation effects in transitions based on niobium with aluminium interlayer which possess small capacitance and VAC high slope of quasi-particle branch. Presented is the VAC of the Nb-Al2O3-Nb transition at T=4.2 K and VAC at heterodyne power effect with the frequency fsub(r)=72 GHz as well as the dependence of the transformed signal on voltage for two signal frequencies: f=72 GHz; f=38 GHz. It is shown that VAC high slope in the region of the knee-like structure in transitions, on the hase of refractory materials permits to increase the transformation effectiveness as well as realize quantum mode even at considerable gap spreadings