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Origin of the spin Seebeck effect in compensated ferrimagnets

Magnons are the elementary excitations of a magnetically ordered system. In ferromagnets, only a single band of low-energy magnons needs to be considered, but in ferrimagnets the situation is more complex owing to different magnetic sublattices involved. In this case, low lying optical modes exist t...

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Detalles Bibliográficos
Autores principales: Geprägs, Stephan, Kehlberger, Andreas, Coletta, Francesco Della, Qiu, Zhiyong, Guo, Er-Jia, Schulz, Tomek, Mix, Christian, Meyer, Sibylle, Kamra, Akashdeep, Althammer, Matthias, Huebl, Hans, Jakob, Gerhard, Ohnuma, Yuichi, Adachi, Hiroto, Barker, Joseph, Maekawa, Sadamichi, Bauer, Gerrit E. W., Saitoh, Eiji, Gross, Rudolf, Goennenwein, Sebastian T. B., Kläui, Mathias
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742853/
https://www.ncbi.nlm.nih.gov/pubmed/26842873
http://dx.doi.org/10.1038/ncomms10452
Descripción
Sumario:Magnons are the elementary excitations of a magnetically ordered system. In ferromagnets, only a single band of low-energy magnons needs to be considered, but in ferrimagnets the situation is more complex owing to different magnetic sublattices involved. In this case, low lying optical modes exist that can affect the dynamical response. Here we show that the spin Seebeck effect (SSE) is sensitive to the complexities of the magnon spectrum. The SSE is caused by thermally excited spin dynamics that are converted to a voltage by the inverse spin Hall effect at the interface to a heavy metal contact. By investigating the temperature dependence of the SSE in the ferrimagnet gadolinium iron garnet, with a magnetic compensation point near room temperature, we demonstrate that higher-energy exchange magnons play a key role in the SSE.