Insulating boundary layer and magnetic scattering in YBa2Cu3O7−δ /Ag interfaces over a contact resistivity range of 10−8–10−3 Ω cm2

We have measured interface transport in thin‐film YBa2Cu3O7−δ /Ag interfaces having resistivities ranging from 10−8 to 10−3 Ω cm2. Analysis of the interface I‐V data indicates that tunneling is the predominant transport mechanism even for the in situ interfaces having contact resistivities of 1–7×10−8 Ω cm2. Zero‐bias conductance peaks are also observed for the entire range of interface resistivity. The similarity of the zero‐bias conductance peaks among these widely varying interfaces suggests that the low‐temperature interface transport is governed by the same mechanism in each case. These conductance peaks are analyzed in the framework of the Appelbaum–Anderson model for tunneling assisted by magnetic scattering from isolated magnetic spins in the interface.

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