Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 20: POSTER Ib
MA 20.23: Poster
Tuesday, March 17, 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)