Seebeck effect in magnetic tunnel junctions
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- 24 July 2011
- journal article
- Published by Springer Science and Business Media LLC in Nature Materials
- Vol. 10 (10), 742-746
- https://doi.org/10.1038/nmat3076
Abstract
The combined magnetic and thermoelectric properties of nanostructures have recently attracted considerable attention. It is now demonstrated that the Seebeck coefficient in a magnetic tunnelling junction is strongly dependent on the magnetic configuration. Creating temperature gradients in magnetic nanostructures has resulted in a new research direction, that is, the combination of magneto- and thermoelectric effects1,2,3,4,5. Here, we demonstrate the observation of one important effect of this class: the magneto-Seebeck effect. It is observed when a magnetic configuration changes the charge-based Seebeck coefficient. In particular, the Seebeck coefficient changes during the transition from a parallel to an antiparallel magnetic configuration in a tunnel junction. In this respect, it is the analogue to the tunnelling magnetoresistance. The Seebeck coefficients in parallel and antiparallel configurations are of the order of the voltages known from the charge–Seebeck effect. The size and sign of the effect can be controlled by the composition of the electrodes’ atomic layers adjacent to the barrier and the temperature. The geometric centre of the electronic density of states relative to the Fermi level determines the size of the Seebeck effect. Experimentally, we realized 8.8% magneto-Seebeck effect, which results from a voltage change of about −8.7 μV K−1 from the antiparallel to the parallel direction close to the predicted value of −12.1 μV K−1. In contrast to the spin–Seebeck effect, it can be measured as a voltage change directly without conversion of a spin current.Keywords
Other Versions
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