Possible mechanism of proximity effect coupled to spin fluctuation in YBa2Cu3Oy/magnetic manganese oxide/YBa2Cu3Oy junctions

Abstract
Current‐voltage characteristics were investigated for YBa2Cu3Oy/La1−xCaxMnOz or La1−xSrxMnOz(200 nm)/YBa2Cu3Oy junctions. The results are discussed together with electrical and magnetic properties of the barrier materials. Supercurrents passed through a 200‐nm‐thick magnetic barrier for certain values of x. The barrier materials did not necessarily have high electric conductivity in this region, but the ferromagnetism nearly disappeared. The results suggested the possible mechanism of a novel kind of proximity effect concerned with magnetism of the barrier.