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How Many Fe layers Cause TMR?

Published online by Cambridge University Press:  01 February 2011

Christian Heiliger ,
Peter Zahn  and
Ingrid Mertig
Christian Heiliger
Affiliation:
c.heiliger@physik.uni-halle.de, Martin Luther University, Department of Physics, Von-Seckendorff-Platz 1, D-06120 Halle, Halle, N/A, N/A, Germany
Peter Zahn
Affiliation:
peter.zahn@physik.uni-halle.de, Martin Luther University, Department of Physics, D-06099 Halle, N/A, N/A, Germany
Ingrid Mertig
Affiliation:
ingrid.mertig@physik.uni-halle.de, Martin Luther University, Department of Physics, D-06099 Halle, N/A, N/A, Germany
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Abstract

The influence of the structural properties of the leads of planar tunnel junctions on the tunneling current is investigated by means of ab initio electronic structure calculations. In particular, a NM/Fe/MgO/Fe/NM tunnel junction with non-magnetic (NM) leads and finite Fe spacer layers between the leads and the MgO barrier is discussed. The conductance is calculated as a function of the number of Fe layers. The results show that even one iron layer next to the barrier is sufficient to obtain a high spin polarization and a high TMR ratio. This finding implies that similar results can be expected for tunnel junctions with nonmagnetic and even amorphous leads, if states of Δ1 symmetry are provided.

Keywords

magnetoresistance (transport)electronic structuremagnetic
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 941: Symposium Q – Magnetic Thin Films, Heterostructures, and Device Materials , 2006 , 0941-Q01-02
Copyright
Copyright © Materials Research Society 2006

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