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Phys. Rev. Lett. 102, 076601 (2009) [4 pages]

Magnetoresistance in Double Spin Filter Tunnel Junctions with Nonmagnetic Electrodes and its Unconventional Bias Dependence

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Guo-Xing Miao*, Martina Müller, and Jagadeesh S. Moodera
Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

Received 18 October 2008; published 17 February 2009

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Spin filtering happens due to the discriminative tunneling probabilities for spin-up and spin-down electrons through a magnetic barrier and can result in highly spin polarized tunnel currents. Combining two such barriers in a tunnel junction thus leads to large magnetoresistance without the necessity of magnetic electrodes. We demonstrate the realization of such unconventional tunnel junctions using double EuS spin filter barriers with Al electrodes. The novel nonmonotonic and asymmetric bias behavior in magnetoresistance can be qualitatively modeled in the framework of WKB approximations.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.102.076601
DOI:
10.1103/PhysRevLett.102.076601
PACS:
72.25.−b, 73.43.Qt, 75.50.Pp

*gxmiao@mit.edu