Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.95: Poster

Donnerstag, 19. März 2015, 09:30–12:00, Poster A

Zinc ferrite based magnetic tunnel junctions — •Michael Bonholzer, Kerstin Brachwitz, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany

Zinc ferrite (ZFO) thin films show promising properties for spintronic device implementation such as semiconducting behaviour [1,3] and ferrimagnetism at room temperature with a high saturation magnetization and coercive field [2,3]. Also a high spin polarisation of charge carriers is predicted [4].

On the basis of zinc ferrite we have built magnetic tunnel junctions on MgO(100) single crystals by pulsed laser deposition (PLD). The junction structure is MgO(substrate)/TiN(20 nm)/ZFO(30 nm)/MgO(1 to 5 nm)/Co(20 nm). Junctions are fabricated by Ar ion sputtering. Here a protecting Ti mask defines the contact areas.

In order to reduce the series resistance of the devices we have added a highly conducting TiN layer underneath the ZFO [5]. RHEED intensity oscillations are visible during PLD-growth of the MgO barrier. The resistance-area product (RA) of the contacts shows a clear exponential dependence on barrier thickness, proving tunneling transport.

[1] A. Marcu et al., J. Appl. Phys. 102 023713 (2007)
[2] C.E. Rodríguez Torres et al., Phys. Rev. B 84, 064404 (2011)
[3] M. Lorenz et al., Phys. Status Solidi RRL 5, 438 (2011)
[4] S. Soliman et al., Phys. Rev. B 83, 085205 (2011)
[5] M.Bonholzer et al., Phys. Status Solidi A 211, 2621 (2014)