Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: POSTER Ib

MA 20.23: Poster

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

Magneto-Seebeck Effect in Magnetic Tunnel Junctions with different barriers — •Ulrike Martens¹, Marvin von der Ehe¹, Jakob Walowski¹, Stefan Niehörster², Alexander Böhnke², Savio Fabretti², Karsten Rott², Günter Reiss², Andy Thomas², and Markus Münzenberg¹ — ¹Inst. f. Phys., Ernst-Moritz-Arndt-Universität Greifswald, Germany — ²CSMD, Physics Department, Bielefeld University, Germany

The first measurements of the tunnel magneto-Seebeck effect (TMS) were reported on magnetic tunnel junctions (MTJs) with a crystalline MgO barrier [1, 2]. Later, Lin et al. have observed the TMS effect in MTJs with Al₂O₃ tunnel barriers [3]. They found a correlation between TMR and TMS that were in the same range and giant thermovoltages of 1 mV, both explained by non-magnetic resonance in the tunnel spectrum responsible for the large thermoelectric effects. For the samples investigated for this presentation, the tunnel magnetoresistance (TMR) and the tunnel magneto-Seebeck effect (TMS) were measured. The MTJs are heated by a modulated diode laser which achieves powers of up to 150 mW. The laser is focused onto the sample in a standard confocal microscope setup. We investigate the power dependence of the TMS ratios. For the different materials, the TMS dependence on the applied bias voltage is studied as well. The first results are used to compare the various barrier materials.

[1] Walter, M., et al.; Nat. Mater. 10, 742-746 (2011)

[2] Liebing, N., et al.; Phys. Rev. Lett. 107, 177201 (2011)

[3] Lin, W., et al.; Nat. Commun. 3, 744 (2012)