Negative Spin Polarization and Large Tunneling Magnetoresistance in Epitaxial Co|SrTiO₃|Co Magnetic Tunnel Junctions

Authors

Julian P. Velev, University of Nebraska-LincolnFollow
Kirill D. Belashchenko, University of Nebraska-LincolnFollow
Derek A. Stewart, Cornell UniversityFollow
Mark van Schilfgaarde, Arizona State UniversityFollow
Sitaram Jaswal, University of NebraskaFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow

Date of this Version

11-18-2005

Comments

Published in Physical Review Letters 95, 216601 (2005).
URL: http://link.aps.org/abstract/PRL/v95/e216601
doi:10.1103/PhysRevLett.95.216601
Copyright 2005 American Physical Society. Used by permission.

Abstract

We perform an ab initio study of spin-polarized tunneling in epitaxial Co|SrTiO₃|Co magnetic tunnel junctions with bcc Co(001) electrodes. We predict a large tunneling magnetoresistance in these junctions, originating from a mismatch in the majority- and minority-spin bands both in bulk bcc Co and at the Co|SrTiO₃ interface. The intricate complex band structure of SrTiO₃ enables efficient tunneling of the minority d electrons which causes the spin polarization of the Co|SrTiO₃ interface to be negative in agreement with experimental data. Our results indicate that epitaxial Co|SrTiO₃|Co magnetic tunnel junctions with bcc Co(001) electrodes are a viable alternative for device applications.