Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 75: Multiferroics II (jointly with DF, DS, KR, MA)

TT 75.7: Vortrag

Mittwoch, 18. März 2015, 16:45–17:00, EB 107

Using multiferroic systems as a spin filter - an ab initio study — •Stephan Borek¹, Jürgen Braun¹, Hubert Ebert¹, Angelika Chassé², Gerd Schönhense³, Hans-Joachim Elmers³, Dmytro Kutnyakhov³, and Ján Minár^1,4 — ¹Ludwig-Maximilians-Universität München — ²Martin-Luther-Universität Halle-Wittenberg — ³Johannes-Gutenberg-Universität Mainz — ⁴University of West Bohemia, Pilsen

Multiferroic heterostructures such as ultrathin Fe/BaTiO₃(001) films are of high interest for technical applications giving the opportunity to control the ferromagnetic state with an electric field or vice versa. In our theoretical study we investigated the effect of changing the electric polarization of the ferroelectric substrate BaTiO₃ on the ferromagnetic state of Fe and Co thin films using the method of Spin Polarized Low Energy Electron Diffraction (SPLEED). This method has been shown to be an effective tool for the investigation of surface properties like the determination of surface magnetic moments and the local crystal structure. The possibility of an application of the multiferroic heterostructures Fe/BTO(001) and Co/BTO(001) as a spin filter is discussed. It will be shown that a change of the polarisation of the BaTiO₃ results in a significant change of the exchange asymmetry giving the possibility to control the diffraction of electrons using the exchange interaction at the Fe (Co) surface. We focus on the systems of 1 ML, 2 ML and 3 ML Fe (Co) on BaTiO₃ because their electronic and magnetic structure as well as the coupling mechanism between the ferroic phases have been intensively discussed in the literature.