C-axis Transport Properties of SmFeAsO0.85 Single Crystals

Electrical transport properties were measured on SmFeAsO0.85 single crystals along the c-axis for various temperatures and magnetic fields. For the measurements a mesa structure was fabricated on the surface of the single crystals. Samples showed a metallic temperature dependence of resistance and current-voltage curves without hysteretic multiple branch splitting that is usually observed in tunneling Josephson junctions. In addition, in ab-planar magnetic fields, samples did not show the Fraunhofer-type field modulation of the critical current. All these features indicate that the c-axis transport characteristics of SmFeAsO0.85 single crystals are explained by the anisotropic bulk superconductivity rather than Josephson tunneling.