Abstract
We deposited the ferromagnetic films, Ni or Fe, on the YBa2Cu3Oy (YBCO) thin films by rf magnetron sputtering technique, and investigated the effects of ferromagnetic films on superconducting characteristics in Ni or Fe/YBCO specimens. From the results, we found that the superconducting transition temperature decreased with increasing the thickness of the magnetic films, in other words superconducting characteristics were degraded by depositing the magnetic films on the high-Tc cuprate superconductors. This indicates that it is possible to fabricate weak electric coupling for Josephson junctions based on the cuprate superconductors by depositing the magnetic films on them.
