Transport measurements on lateral MgB2/Fe/MgB2 junctions

The magnetic anisotropy and transport properties of superconducting MgB2 thin films on MgO (100) substrates were studied. The films were prepared by rf/dc-magnetron cosputtering and with in situ annealing temperatures of 650 °C. The film orientation was measured by X-ray diffractometry, which revealed a c-axis orientation of the MgB2 films. The critical onset temperature without field cooling is 15.5 K. We found a critical field of 14.73 T parallel to the film plane and 10.79 T perpendicular to the film plane from transport measurements of the dependence of the applied magnetic field. Differential conductance measurements of a lateral MgB2/Fe/MgB2 junction show the Δπ gap and the Δσ gap.