Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: POSTER Ib

MA 20.26: Poster

Dienstag, 17. März 2015, 09:30–13:00, Poster A

Ab initio investigation of the tunneling magneto Seebeck effect — •Christian Franz, Michael Czerner, and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University, Giessen, Germany

The Seebeck coefficient describes the thermoelectric voltage induced in a junction by a temperature gradient. In a magnetic tunnel junction the Seebeck coefficient depends on the relative orientation of the magnetizations; this effect is termed tunneling magneto-Seebeck effect (TMS). The TMS has been predicted theoretically [1] and confirmed experimentally [2].

In this contribution we investigate the TMS in MgO-based tunnel junctions using ab initio methods [3]. We investigate the TMS for Fe_xCo_1−x leads [4,5] with varying alloy composition, barrier thickness, temperature, and applied bias voltage. We find that the TMS depends sensitively on the parameters, in particular the alloy composition. This behavior can be traced back to the respective dependence of the transmission function. We also show recent results using Heusler alloys for the leads.

[1] M. Czerner, M. Bachmann, C. Heiliger, Phys. Rev. B 83, 132405 (2011).

[2] M. Walter et. al, Nat. Mater. 10, 742 (2011).

[3] C. Franz, M. Czerner, C. Heiliger, J. Phys.: Condens. Matter 25, 425301 (2013).

[4] C. Heiliger, C. Franz, M. Czerner, Phys. Rev. B 87, 224412 (2013).

[5] C. Franz, M. Czerner, C. Heiliger, Phys. Rev. B 88, 094421 (2013).