Electroresistance in superconductor-ferroelectric-superconductor junctions

In tunnel junctions with a ferroelectric barrier, a large resistance variation is observed upon ferroelectric switching, which can be induced by a short voltage pulse. Known as electro-resistance, this phenomenon is connected to the interfacial screening of the electric field generated by the ferroelectric in the junction's electrodes. Usually realized in junctions with normal-metal electrodes, here we experimentally investigate these effects in junctions that combine the ferroelectric BiFeO$_{\mathrm{3}}$ and different types of superconducting electrodes. Using piezo-response force microscopy and electrical measurements, we find an unusual temperature dependence of the electroresistance, which reaches up to 10$^{\mathrm{4}}${\%} .The effects are discussed in terms of the interface charge-carrier depletion produced in the superconducting electrodes...