Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster Session I

DS 17.46: Poster

Dienstag, 13. März 2018, 18:15–20:15, Poster B

Electrical conductivity measurements of ultrathin ferrite films on MgO(001) — •Tobias Pollenske, Jari Rodewald, Tobias Pohlmann, and Joachim Wollschläger — Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany

The semiconducting and ferrimagnetic behavior make ultrathin epitaxial ferrite films like NiFe₂O₄ or CoFe₂O₄ promising candidates in the field of spintronics. Due to their spin dependent tunneling barrier they are well-suited to be used as spin filters. Here, the resistance of the films is a crucial property for the formation of suitable tunneling barriers and thus for the performance as a spin filter.

Hence, in this work a measurement setup is taken into operation to investigate the temperature dependent conductivity of ultrathin ferrite films. First, different types of contacts in van-der-Pauw geometry are tested in order to optimize the performance of the measurement setup. Furthermore, ultrathin Ni_xFe_3−xO₄ films on MgO(001) with different stoichiometries (0 ≤ x ≤ 2) are prepared via reactive molecular beam epitaxy (RMBE) and their conductivity is analyzed with respect to the different cation ratios.