Spinterface Effects in Hybrid LaSrMnO/SrTiO/C/Co Magnetic Tunnel Junctions.

Orbital hybridization at the Co/C interface been has proved to strongly enhance the magnetic anisotropy of the cobalt layer, promoting such hybrid systems as appealing components for sensing and memory devices. Correspondingly, the same hybridization induces substantial variations in the ability of the Co/C interface to support spin-polarized currents and can bring out a spin-filtering effect. The knowledge of the effects at both sides allows for a better and more complete understanding of interfacial physics. In this paper we investigate the Co/C bilayer in the role of a spin-polarized electrode in the LaSrMnO/SrTiO/C/Co configuration, thus substituting the bare Co electrode in the well-known LaSrMnO/SrTiO/Co magnetic tunnel junction. The study revealed that the spin polarization (SP) of the tunneling currents escaping from the Co/C electrode is generally negative: i.e., inverted with respect to the expected SP of the Co electrode. The observed sign of the spin polarization was confirmed via DFT calculations by considering the hybridization between cobalt and molecular orbitals.