The magnetotransport properties of La0.7Sr0.3MnO3/BaTiO3 superlattices grown by pulsed laser deposition technique

We have investigated the magnetotransport properties of La0.7Sr0.3MnO3/BaTiO3 superlattices, grown on SrTiO3 substrate by pulsed laser deposition technique, both with current-in-plane and current-perpendicular-to-the-plane directions. Several features indicate the presence of magnetic inhomogeneities at the interfaces which is independent of BaTiO3 layer thickness variation. First, the magnetic property in the superlattices decreases. Second, a hysteresis in magnetoresistance due to the relaxation of the resistive state is observed. Third, a threshold under an applied magnetic field in the magnetoresistance is seen. Such behaviors are in agreement with the phase separation scenario which could be the possible reason for these magnetic inhomogeneities at the interfaces. On the contrary, the magnetoresistance with the current-perpendicular-to-the-plane direction is mostly attributed to the tunneling effect along with the ordering of the spin at the interface. This study confirms the importance of the interfaces in superlattices that can be used to control novel physical properties in oxide materials.