Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.14: Poster
Freitag, 4. April 2014, 10:30–13:30, P2
Large tunnel magneto-Seebeck effect in Co2FeSi Heusler compound — •Alexander Boehnke1, Marvin Walter2, Christian Sterwerf1, Michael Czerner3, Karsten Rott1, Andy Thomas1, Christian Heiliger3, Markus Münzenberg2, and Günter Reiss1 — 1Thin Films and Physics of Nanostructures, Bielefeld University, Germany — 2I. Physikalisches Institut, Georg-August-Universität Göttingen, Germany — 3I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Germany
Heusler compounds are promising candidates for magnetic tunnel junctions (MTJ) as their potential high spin polarization leads to high tunnel magnetoresistance (TMR) ratios. Recently the tunnel magneto-Seebeck effect (TMS), that occurs when a temperature gradient is applied to an MTJ, has gained much interest. Our measurements show that Heusler compounds can give a good thermoelectric readout contrast, which is beneficial for future applications in, e.g., green information technology.
We investigated Co2FeSi/MgO/Co70Fe30 MTJs. Interestingly, the TMS ratio (96 %) is comparable to the TMR ratio (101 %). Similar effects were found for Al2O3 barrier MTJs, but both observations differ from CoFeB/MgO/CoFeB MTJs, where the TMS is much smaller than the TMR. This reveals a strong influence of the contributing transport bands on the TMS, basically different from the TMR. Further ab initio calculations are pending to gain a proper understanding of these fundamental effects.