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Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites

The spin-Seebeck effect (SSE) is an advective transport process traditionally studied in bilayers composed of a ferromagnet (FM) and a non-magnetic metal (NM) with strong spin-orbit coupling. In a temperature gradient, the flux of magnons in the FM transfers spin-angular momentum to electrons in the...

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Autores principales: Wooten, Brandi L., Vandaele, Koen, Boona, Stephen R., Heremans, Joseph P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589084/
https://www.ncbi.nlm.nih.gov/pubmed/33096864
http://dx.doi.org/10.3390/nano10102083
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author Wooten, Brandi L.
Vandaele, Koen
Boona, Stephen R.
Heremans, Joseph P.
author_facet Wooten, Brandi L.
Vandaele, Koen
Boona, Stephen R.
Heremans, Joseph P.
author_sort Wooten, Brandi L.
collection PubMed
description The spin-Seebeck effect (SSE) is an advective transport process traditionally studied in bilayers composed of a ferromagnet (FM) and a non-magnetic metal (NM) with strong spin-orbit coupling. In a temperature gradient, the flux of magnons in the FM transfers spin-angular momentum to electrons in the NM, which by the inverse spin-Hall effect generates an SSE voltage. In contrast, the Nernst effect is a bulk transport phenomenon in homogeneous NMs or FMs. These effects share the same geometry, and we show here that they can be added to each other in a new combination of FM/NM composites where synthesis via in-field annealing results in the FM material (MnBi) forming aligned needles inside an NM matrix with strong spin-orbit coupling (SOC) (Bi). Through examination of the materials’ microstructural, magnetic, and transport properties, we searched for signs of enhanced transverse thermopower facilitated by an SSE contribution from MnBi adding to the Nernst effect in Bi. Our results indicate that these two signals are additive in samples with lower MnBi concentrations, suggesting a new way forward in the study of SSE composite materials.
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spelling pubmed-75890842020-10-29 Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites Wooten, Brandi L. Vandaele, Koen Boona, Stephen R. Heremans, Joseph P. Nanomaterials (Basel) Article The spin-Seebeck effect (SSE) is an advective transport process traditionally studied in bilayers composed of a ferromagnet (FM) and a non-magnetic metal (NM) with strong spin-orbit coupling. In a temperature gradient, the flux of magnons in the FM transfers spin-angular momentum to electrons in the NM, which by the inverse spin-Hall effect generates an SSE voltage. In contrast, the Nernst effect is a bulk transport phenomenon in homogeneous NMs or FMs. These effects share the same geometry, and we show here that they can be added to each other in a new combination of FM/NM composites where synthesis via in-field annealing results in the FM material (MnBi) forming aligned needles inside an NM matrix with strong spin-orbit coupling (SOC) (Bi). Through examination of the materials’ microstructural, magnetic, and transport properties, we searched for signs of enhanced transverse thermopower facilitated by an SSE contribution from MnBi adding to the Nernst effect in Bi. Our results indicate that these two signals are additive in samples with lower MnBi concentrations, suggesting a new way forward in the study of SSE composite materials. MDPI 2020-10-21 /pmc/articles/PMC7589084/ /pubmed/33096864 http://dx.doi.org/10.3390/nano10102083 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Wooten, Brandi L.
Vandaele, Koen
Boona, Stephen R.
Heremans, Joseph P.
Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title_full Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title_fullStr Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title_full_unstemmed Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title_short Combining Spin-Seebeck and Nernst Effects in Aligned MnBi/Bi Composites
title_sort combining spin-seebeck and nernst effects in aligned mnbi/bi composites
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589084/
https://www.ncbi.nlm.nih.gov/pubmed/33096864
http://dx.doi.org/10.3390/nano10102083
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