Impurity-Assisted Interlayer Exchange Coupling across a Tunnel Barrier

Authors

Mikhail Ye Zhuravlev, University of Nebraska-LincolnFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
A. V. Vedyayev, M. V. Lomonosov Moscow State University

Date of this Version

1-21-2005

Comments

Published in Physical Review Letters 94, 026806 (2005).
URL: http://link.aps.org/abstract/PRL/v94/e026806
doi:10.1103/PhysRevLett.94.026806
Copyright 2005 American Physical Society. Used by permission.

Abstract

Localized impurity or defect states in the insulating barrier layer separating two ferromagnetic films affect dramatically the interlayer exchange coupling (IEC), making it significantly stronger compared to perfect barriers. We demonstrate that the impurity-assisted IEC becomes antiferromagnetic if the energy of the impurity states matches the Fermi energy and that the coupling strength decreases with temperature. These results explain available experimental data on the IEC across tunnel barriers.