Magnetic dependent proximity effects of superconductivity and ferromagnetism in YBa2Cu3O7-(o)over-bar/La1-xCaxMnO3 bilayers

摘要

The YBa2CU3O7-o/La0.88Ca0.12MnO3 (YBCO/LCMOi) and YBa2CU3O7-o/La0.33Ca0.67MnO3 (YBCO/LCMOj) bilayers are fabricated with the method of pulsed laser deposition, and the magnetic dependent proximity effects are investigated. The magnetic fields were applied parallel (in-plane) and perpendicular (out-of-plane) to the film plane. Magnetic properties curves in different temperature range and magnetic field along two crystal orientation show a complex behavior due to the interplay between Meissner currents in YBCO layer and the magnetic fields present in LCMOi (or LCMOj) layer. Ac susceptibility measurements show that the suppression Of Superconductivity in LCMOi and LCMOj bilayers. The obtained results are discussed in terms of the effect of hole charge transfer from YBCO to LCMOi (or LCMOj) on the proximity between superconductivity and ferromagnetism.