Atomic and Electronic Structure of Co/SrTiO₃/Co Tunnel Junctions

Authors

Ivan I. Oleinik, University of Oxford, Oxford, UKFollow
Evgeny Y. Tsymbal, University of Nebraska at LincolnFollow
David G. Pettifor, University of OxfordFollow

Date of this Version

12-2001

Comments

Published in Physical Review B 65, R020401 (2002). Copyright © 2001 The American Physical Society. Used by permission. doi: 10.1103/PhysRevB.65.020401.

Abstract

First-principles density-functional calculations of the atomic and electronic structure of Co/SrTiO₃ /Co (001) magnetic tunnel junctions (MTJ’s) are performed. Different interface terminations are considered and the most stable structure with the TiO₂ termination is identified based on energetics of adhesion. The calculated electronic structure of the TiO₂-terminated MTJ shows an exchange coupling between the interface Co and Ti atoms mediated by oxygen. This coupling induces a magnetic moment of 0.25 µ_B on the interface Ti atom, which is aligned antiparallel to the magnetic moment of the Co layer. We argue that this might cause an inversion of the spin polarization of tunneling across the SrTiO₃ barrier which was found in recent experiments.