Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 37: Spin Dependent Transport Phenomena

MA 37.1: Vortrag

Donnerstag, 26. März 2009, 15:15–15:30, HSZ 403

Spin-polarized tunneling through SrTiO₃ and BaTiO₃ barriers — •Daniel Wortmann and Stefan Blügel — Institut für Festkörperforschung and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany

With the increased experimental control in growing transition-metal oxides in thin films of high quality, the fabrication of tunneljunctions containing e.g. SrTiO₃ and BaTiO₃ barriers became possible. Such junctions can be viewed as the prototype of new oxide-electronic devices employing the rich physics of transition-metal oxides for novel functionalities. In particular the large dielectric response of e.g. SrTiO₃ or even the ferroelectricity of BaTiO₃ can be exploited for innovative tunneling setups.

We present ab initio calculations of spin-polarized transport in tunneljunctions with magnetic SrRuO₃ leads and SrTiO₃ and BaTiO₃ insulating barriers. These calculations have been performed within the FLAPW method as implemented in the Jülich FLEUR code (www.flapw.de) and utilize the newly developed linearly scaling Green-function method that will presented in another presentation of this conference [1]. Detailed studies of the electronic structure of the barrier, i.e. of their complex bandstructure, will be presented demonstrating that these materials form significantly more complex barriers than simple oxides like MgO.

Support from the SPP-1243 of the DFG is gratefully acknowledged.

[1] F. Freimuth, D. Wortmann, S. Blügel, Embedding based order-N implementation of the FLAPW method