Large Magnetoresistance at Oxide La0.7Ca0.3MnO3 and YBa2Cu3O7 Interfaces
We report magnetoresistance in ferromagnet / superconductor / ferromagnet structures made of La0.7Ca0.3MnO3 and YBa2Cu3O7 in the current in plane (CIP) geometry when the temperature is fixed along the superconducting transition and the magnetic field is swept in an hysteresis loop sequence. We describe experiments changing the geometry of current versus field. We find that the shape and height of the magnetoresistance peaks is not modified no matter the field is directed parallel or perpendicular to the current. This excludes interpretations in terms of spontaneous vortices or anisotropic magnetoresistance of the ferromagnetic layers and supports the view that the magnetoresistance phenomenon originates at the spin dependent transport of quasiparticles transmitted from the ferromagnetic electrodes into the superconductor.
V. Peña et al., "Large Magnetoresistance at Oxide La0.7Ca0.3MnO3 and YBa2Cu3O7 Interfaces", Advances in Science and Technology, Vol. 45, pp. 2545-2553, 2006