Anomalous Superconducting Proximity Effect in Hybrid Oxide Heterostructures with Antiferromagnetic Layer

We report an investigation of current transport in Nb/Au/CaSrCuO/YBaCuO heterostructures including an antiferromagnetic interlayer (CaSrCuO). Epitaxial thin films of YBaCuO and CaSrCuO were grown by laser ablation on NdGaO substrates; the thicknesses of CaSrCuO films were 20 and 50 nm, and x=0.15 or 0.5. Our experimental results show that the superconducting current transport is increased in the Nb/Au/CaSrCuO/YBaCuO heterostructures in comparison with the ones observed in previously studied Nb/Au/YBaCuO heterostructures. It was found that the critical current of the structure is very sensitive to the absolute value and direction of the external magnetic field.