CONTROL OF THE VORTEX MOVEMENT AND ARRANGEMENT BY OUT-OF-PLANE MAGNETIC STRUCTURES IN TWINNED YBa2Cu3O7−x/La0.67Sr0.33MnO3 BILAYER

In this article, we consider the magnetic interaction exerted on vortices in a thin YBa2Cu3O7−x film by a La0.67Sr0.33MnO3 layer. The magnetic coupling of the bilayer system was studied and locally imaged by means of magneto-optics. Twin boundaries in the LaAlO3 substrate cause a clear splitting of the manganite magnetic domains with well-defined in-plane magnetization separated by pinned out-of-plane magnetic structures. The vortices nucleated by the external magnetic field interact with the out-of-plane magnetic moments depending on their local structure and magnetic polarization. Different blocking mechanisms ssink or reservoird are found for the vortex motion perpendicular to twin boundaries, whereas for vortices moving parallel to the out-of-plane magnetic structures either blocking or channelling effect is observed.