POINT-CONTACT INVESTIGATION ON BI2SR2CACU2O8-FILMS(Y THIN)

We have measured point contacts with a gold tip on Bi2Sr2CaCu2O8+y thi n films and Bi2Sr2CaCu2O8+y/SrTiO3 double layers. The results show tun neling or direct conductivity behaviour depending on the junction para meters and can be fitted by corresponding theoretical models. From fit ting procedure of differential characteristics by modified Blonder-Tin bham-Klapwijk (BTK) theory the Fermi velocity v(F) = 5 x 10(5) m/s, ra tio 2 Delta(4.2K)/kT(c) = 7.9 and coherence length xi(ab) = 3.5 mm wer e obtained. The changing of the interface transmission by additional l ayers of different thickness corresponding to metallic or insulating b ehaviour is shown. In the frame of the inelastic scattering of quasipa rticles the linear background of differential conductance is discussed .