Bias Voltage Dependence of Tunneling Anisotropic Magnetoresistance in Magnetic Tunnel Junctions with MgO and Al₂O₃ Tunnel Barriers

Authors

• Li Gao, IBM Research Division, Almaden Research Center, San Jose, California
• Xin Jiang, IBM Research Division, Almaden Research Center, San Jose, California
• See-Hun Yang, IBM Research Division, Almaden Research Center, San Jose, California
• John D. Burton, University of Nebraska-LincolnFollow
• Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
• Stuart S. P. Parkin, IBM Research Division, Almaden Research Center, San Jose, California

ORCID IDs

Tsymbal http://orcid.org/0000-0002-6728-5486

Document Type

Article

Date of this Version

11-2007

Citation

Physical Review Letters (2007) 99: 226602

doi: 10.1103/PhysRevLett.99.226602

Comments

Copyright © 2007, American Physical Society. Used by permission

Abstract

Tunneling anisotropic magnetoresistance (TAMR) is observed in tunnel junctions with transition metal electrodes as the moments are rotated from in-plane to out-of-plane in sufficiently large magnetic fields that the moments are nearly parallel to one another. A complex angular dependence of the tunneling resistance is found with twofold and fourfold components that vary strongly with bias voltage. Distinctly different TAMR behaviors are obtained for devices formed with highly textured crystalline MgO(001) and amorphous Al₂O₃ tunnel barriers. A tight-binding model shows that a fourfold angular dependence can be explained by the presence of an interface resonant state that affects the transmission of the contributing tunneling states through a spin-orbit interaction.