Magnon Mode Selective Spin Transport in Compensated Ferrimagnets

Joel Cramer, Er-Jia Guo, Stephan Geprägs, Andreas Kehlberger, Yurii P. Ivanov, Kathrin Ganzhorn, Francesco Della Coletta, Matthias Althammer, Hans Huebl, Rudolf Gross, Jürgen Kosel, Mathias Kläui, Sebastian T. B. Goennenwein

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

We investigate the generation of magnonic thermal spin currents and their mode selective spin transport across interfaces in insulating, compensated ferrimagnet/normal metal bilayer systems. The spin Seebeck effect signal exhibits a nonmonotonic temperature dependence with two sign changes of the detected voltage signals. Using different ferrimagnetic garnets, we demonstrate the universality of the observed complex temperature dependence of the spin Seebeck effect. To understand its origin, we systematically vary the interface between the ferrimagnetic garnet and the metallic layer, and by using different metal layers we establish that interface effects play a dominating role. They do not only modify the magnitude of the spin Seebeck effect signal but in particular also alter its temperature dependence. By varying the temperature, we can select the dominating magnon mode and we analyze our results to reveal the mode selective interface transmission probabilities for different magnon modes and interfaces. The comparison of selected systems reveals semiquantitative details of the interfacial coupling depending on the materials involved, supported by the obtained field dependence of the signal.
Original languageEnglish (US)
Pages (from-to)3334-3340
Number of pages7
JournalNano Letters
Volume17
Issue number6
DOIs
StatePublished - Apr 13 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors express their gratitude to Professor Gerrit E. W. Bauer and Dr. Joe Barker for valuable discussions and the Institute for Materials Research at Tohoku University for the hospitality during a visiting researcher stay (M.K.). Furthermore, they would like to thank Professor Kathrin Dorr for the help in sample preparation. This work was supported by Deutsche Forschungsgemeinschaft (DFG) SPP 1538 Spin Caloric Transport, the Graduate School of Excellence Materials Science in Mainz (MAINZ, DFG/GSC 266), and the EU projects (IFOX, NMP3-LA-2012246102, INSPIN FP7-ICT-2013-X 612759) and the DAAD (SpinNet and MaHoJeRo during the manuscript preparation). During the manuscript preparation, this work was also partially supported by the U.S. Department of Energy (DOE), Office of Science (OS), Basic Energy Sciences (BES), and by the Laboratory Directed Research and Development (LDRD) Program of Oak Ridge National Laboratory (ORNL) managed by UT-Battelle, LLC, for the U.S. DOE.

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