Memory effects in manganite spintronic devices

We fabricate sub-micrometric constrictions in manganite epitaxial thin films by atomic force microscope local anodization and focused ion beam. We demonstrate the possibility of realising planar spin valve devices, exhibiting hysteretic transport behaviour as a function of the external magnetic field, associated with magnetic domains orientation. We also observe non-linear currentvoltage characteristics which become increasingly linear in external field and we attribute this crossover to magnetic domain alignment as well. By carrying out differential resistance measurements at different magnetic fields, we find evidence of hysteric resistance behaviour as a function of both the external magnetic field and dc bias current. We interpret this phenomenology in terms of magnetic domain rotation by spin torque induced by the polarised current. These memory effects could be in perspective exploited in spintronics devices.