A novel proximity effect between superconductor and magnetic manganese oxide

A novel proximity effect between superconductor and magnetic manganese oxide has been found. To investigate interactions between superconductor and magnetic materials, we have fabricated both trilayered-type and coplanar-type junctions and investigated their current-voltage characteristics. The magnetic material was La 1-x Ca x MnO z (LCMO) or La 1-x Sr x MnO z (LSMO) manganese oxide. In YBCO/LCMO/YBCO junctions, supercurrents were observed through a magnetic barrier as thick as 500 nm. This phenomenon was also confirmed by coplanar junctions. The effect of magnetism of the barrier material was investigated. It was found that this proximity effect occurred only in a limited region where spin fluctuations are considered to exist.