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arXiv · 1707.00505

Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes

Alexander Boehnke·Ulrike Martens·Christian Sterwerf·Alessia Niesen·Torsten Huebner·Marvin von der Ehe·Markus Meinert·Timo Kuschel·Andy Thomas·Christian Heiliger·Markus Münzenberg·Günter Reiss
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Abstract

Spin caloritronics studies the interplay between charge-, heat- and spin-currents, which are initiated by temperature gradients in magnetic nanostructures. A plethora of new phenomena has been discovered that promises, e.g., to make wasted heat in electronic devices useable or to provide new read-out mechanisms for information. However, only few materials have been studied so far with Seebeck voltages of only some μV, which hampers applications. Here, we demonstrate that half-metallic Heusler compounds are hot candidates for enhancing spin-dependent thermoelectric effects. This becomes evident when considering the asymmetry of the spin-split density of electronic states around the Fermi level that determines the spin-dependent thermoelectric transport in magnetic tunnel junctions. We identify Co$_2$FeAl and Co$_2$FeSi Heusler compounds as ideal due to their energy gaps in the minority density of states, and demonstrate devices with substantially larger Seebeck voltages and tunnel magneto-Seebeck effect ratios than the commonly used Co-Fe-B based junctions.

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Alexander Boehnke, Ulrike Martens, Christian Sterwerf, Alessia Niesen, Torsten Huebner, Marvin von der Ehe, Markus Meinert, Timo Kuschel, Andy Thomas, Christian Heiliger, Markus Münzenberg, Günter Reiss. 2017-11-20. Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes. https://doi.org/10.1038/s41467-017-01784-x

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