Characterization of high-Tc ramp-type Josephson junctions constructed with a Nd2CuO4 barrier

High-T-c ramp-type Josephson junctions were fabricated using a Nd2CuO4 barrier. Such a Nd2CuO4 material has excellent structural, thermal and chemical compatibility with YBa2Cu3O7-delta. Its very stable 214-T' structure, superior electric properties and closed lattice matching make it desirable to construct multilayer junctions. The growth and nature of the heteroepitaxial Nd2CuO4/YBa2Cu3O7-delta structures were investigated by using x-ray diffraction, small angle x-ray reflection, rocking curve, electron microscopy and surface scan measurements. Junctions with a Nd2CuO4 barrier display typical resistively shunted junction-like I-V characteristics with reasonable IcRn products. The large normal resistance, absence of the potential barrier at the SN boundary and a high transparency for the quasi-particles show the advantages of the Nd2CuO4 barrier. The temperature dependence of Josephson parameters and the transport process were studied and discussed.